Stealth in military aviation, pros and cons

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shiv
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Stealth in military aviation, pros and cons

Postby shiv » 02 Sep 2016 08:28

This is not a topic that has been discussed separately on BRF and I think so much water has flowed down the Cooum that there are a few things that are worth talking about.

First a disclaimer:
None of what I write below is being written as holy law. I am not trying to argue that stealth is good, bad or indifferent. This is just information and titbits I have gathered and may be coloured by my biases. I am merely posting some issues as a jumping off point for people to say what they think or they know.

I am not talking about stealth in land warfare and sea war because they are well known. It is aviation stealth that has made rapid strides in recent decades.

The US was first off the mark in demonstrating the use of stealth. The "Blackbird" was noisy and hot, but it was supersonic and the black was to keep it stealthy and it set set the stage for later stealth aircraft. The F-117 was, to my knowledge, spectacular in Bosnia as well as the first Iraq war, achieving amazing breakthroughs via SEAD. This was followed by the B-2. The US followed this up with the ostensibly superlative F-22 with all aspect stealth. And now we have the F-35, apparently also very stealthy.

For the moment I am not going to talk about the Chinese and Russian attempts at stealthy aircraft, but let me move on to some "cons" of stealth. I am not going into any arguments but simply posting information as I have read it over the years

Stealth and top class aerodynamic performance do not sit well together. Stealth requires features that reduce agility and aerodynamic performance and this can be countered by thrust vectoring, very efficient engines and fly-by-wire as was done in the F-22. Stealth also has the reputation of being maintenance intensive where the skin surface has to be kept free from dents, dirt and artefacts that reduce stealth. We have also discussed time and again about how internal weapons bays reduce payload carrying capacity. External carriage reduces stealth

Finally I want to add the fact that many countries on the world, faced with extreme stealth have invested in technology to detect stealthy aircraft. To my knowledge these include IR sensors and appropriate radars. Some of these radars are very high powered - the idea being that even small radar returns will come back stronger. Of course there are arguments against the effectiveness of all this, but I am not going into that - will leave it for others.

The other related issue is the fact that stealth tech can be used "partially". For example an aircraft can be stealthy from the frontal aspect, which is what will face the enemy when they fly in. After a raid - the presence of aircraft is already known, so escape can be achieved by conventional means like afterburners and low level getaway. To an extent Russia and China have gone down this route.

A final point is that the world is full of unstealthy aircraft but detection of stealth is improving, so a lot of effort seems to be going into making existing unstealthy aircraft a little more stealthy by using various means like radar absorbent coatings and increasing use of composites.

So while stealth is here to stay, what the future holds for military aviation is a mixed bag because the issue is still in a flux and I thought this might be a good time to talk about what is happening.

Where is brar?

Manish_Sharma
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Re: Stealth in military aviation, pros and cons

Postby Manish_Sharma » 02 Sep 2016 19:34

Before BRF days, for me the stealth aircraft only meant a dibba-bund blackish aircraft with shapes from batman movies.

Slowly slowly it became clear that its much more than, when first time Shiv ji brought ideas of prodyut das and a big discussion happened, one amazing thing I found out was that stealthy aircraft while super-cruising will have a very hot skin due to drag and will be visible on russian irst due to hotness. So for the first time it was revealed to me that f-22 etc. are only radar invisible but not irst invisible.

Then it was revealed that the moment a fighter switches on the radar; it broadcasts its location to enemy also. So special radar is developed for f 22 which is called lpi and it detects enemy with broadcasting itself.

Few days before brf went down it was brar_w who said that certain old radars can see where f 22 is but can't use the certain bandwidth of radars to track-n-target it with missiles. While B2 can't even be detected by that radar.

Now another news item I read recently where they said that certain discovery in US in 1928 was "Static Charge" makes things free or reduce the gravity. Which is used in B2 to make it lighter, which was all sold to china by a Parsi gentleman who created designed B2 and he was jailed in 2006 for 32 years :
http://www.bibliotecapleyades.net/ciencia/ciencia_flyingobjects44.htm
Electrogravitic (antigravity) technology, under development in U.S. Air Force black R&D programs since late 1954, may now have been put to practical use in the B-2 Advanced Technology Bomber to provide an exotic auxiliary mode of propulsion.

This inference is based on the recent disclosure that the B-2 charges both its wing leading edge and jet exhaust stream to a high voltage.

Positive ions emitted from its wing leading edge would produce a positively charged parabolic ion sheath ahead of the craft while negative ions injected into it's exhaust stream would set up a trailing negative space charge with a potential difference in excess of 15 million volts. According to electrogravitic research carried out by physicist T. Townsend Brown, such a differential space charge would set up an artificial gravity field that would induce a reactionless force on the aircraft in the direction of the positive pole.

An electrogravitic drive of this sort could allow the B-2 to function with over-unity propulsion efficiency when cruising at supersonic velocities.

For many years rumors circulated that the U.S. was secretly developing a highly advanced, radar-evading aircraft. Rumor turned to reality in November of 1988, when the Air Force unveiled the B-2 Advanced Technology Bomber. Although military spokesmen provided the news media with some information about the craft's outward design, and low radar and infrared profile, there was much they were silent about. However, several years later, some key secrets about the B-2 were leaked to the press.

On March 9, 1992, "Aviation Week and Space Technology" magazine made a surprising disclosure that the B-2 electrostatically charges its exhaust stream and the leading edges of its wing-like body. Those familiar with the electrogravitics research of American physicist T. Townsend Brown will quickly realize that this is tantamount to stating that the B-2 is able to function as an antigravity aircraft.

"Aviation Week" obtained their information about the B-2 from a small group of renegade west coast scientists and engineers who were formerly associated with black research projects. In making these disclosures, these scientists broke a code of silence that rivals the Mafia's. They took the risk because they felt that it was important for economic reasons that efforts be made to declassify certain black technologies for commercial use.

Two of these individuals said that their civil rights had been blatantly abused (in the name of security) either to keep them quiet or to prevent them from leaving the tightly controlled black R&D community.

Several months after "Aviation Week" published the article, black world security personnel went into high gear. That sector of the black R&D community received VERY STRONG warnings and, as a result, the group of scientists subsequently broke off contact with the magazine. Clearly, the overseers of black R&D programs were substantially concerned about the information leaks that had come out in that article.

To completely understand the significance of what was said about the B-2, one must first become familiar with Brown's work. Beginning in the mid 1920's, Townsend Brown discovered that it is possible to create an artificial gravity field by charging an electrical capacitor to a high-voltage.

He specially built a capacitor which utilized a heavy, high charge-accumulating (high K-factor) dielectric material between its plates and found that when charges with between 70,000 to 300,000 volts, it would move in the direction of its positive pole. When oriented with its positive side up, it would proceed to lose about 1 percent of it's weight.

He attributed this motion to an electrostatically-induced gravity field acting between the capacitor's oppositely charged plates. By 1958, he had succeeded in developing a 15 inch diameter model saucer that could lift over 110% of its weight!


What happens when F 22 attacking china is detected by old tech ground radar and china launches cheap UCAVs equiped with IRSTs in that location folloed by su 30mkk, now how many of these drones f22 can kill to stay stealthy and while it kills them it'll sure launch missiles/bullets making it unstealthy for those moments to be confronted with 30mkk.

usaf operates 600 f-15s? But they decided not to replace them with f 22 which needed 30 hrs maintenance for 1 hour flying. Stopped producing them at 181.

While they decided to make cheaper stealthy f-16 replacement as F-35 which again ate up 1 trillion dollar.

IAF prefers non-stealthy (5 gen context) Rafale, but doesn't want 5 gen FGFA, but PMO has to push for it.

Is there a possbility in future that instead of ground radars, a fighter nose radar will be able to detect another stealth a/c be it pakfa, jsf or j20?

Manish_Sharma
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Re: Stealth in military aviation, pros and cons

Postby Manish_Sharma » 03 Sep 2016 16:46

B-2 Bomber upto now was considered as ultimate stealth platform, now it is revealed that it is no more stealthy and to counter the low frequency radars that can detect and track tactical fighter-sized stealth aircraft they need B-21.

http://nationalinterest.org/blog/the-buzz/americas-lethal-new-b-21-vs-the-b-2-stealth-bomber-15352

With the U.S. Air Force revealing concept art and a designation for its shadowy Northrop Grumman B-21 Long Range Strike-Bomber (LRS-B) last week, there are many details that we can now glean about the new warplane.

First and foremost, the new B-21 looks very similar to its B-2 Spirit predecessor. In fact, the new aircraft look startlingly similar to the original Advanced Strategic Penetration Aircraft (ASPA) and the later Advanced Technology Bomber concept from the 1980s that ultimately resulted in the B-2. But the Spirit was redesigned late in the game to operate at low altitudes after Dr. Paul Kaminski’s—current chairman of the Defense Science Board—Red Team cautioned that the B-2 might have to resort to low-level penetration as the Soviets built new, more capable radars—as legendary Aviation Week journalist Bill Sweetman points out in his book “Inside the Stealth Bomber.” The redesign caused a decrease in range and payload, as well as a larger radar cross-section.

If the current B-21 design is truly representative of the direction the Air Force is taking, the new aircraft will take the B-2’s all-aspect stealth design to the next level. Particularly, the B-21’s low observable design will be more effective against low frequency radars operating in the UHF and VHF bands, which are increasingly coming into vogue as a means to counter stealth aircraft. Indeed, as then Air Force chief of staff Gen. Norton Schwartz told the House Armed Services Committee in 2012, even the B-2 is starting to lose its ability penetrate hostile airspace. “The technology on which they were designed with respect to signature management . . . is ‘80s vintage,” Schwartz told the committee, adding, “the reality is that the B-2 over time is going to become less survivable in contested airspace.”

The B-21 design—which is similar to the original high-attitude optimized B-2 design—is built to counter the low frequency radars that can detect and track tactical fighter-sized stealth aircraft. Unlike an F-22 or F-35, which are designed to operate in an environment where the enemy might be aware of their presence, the B-2 and B-21 are designed to avoid detection altogether. Basically, the B-21 (and B-2 to an extent)—with its large flying-wing design—reduces its low frequency radar cross-section to the point where it blends in with the background noise inherent to those UHF/VHF band systems. That’s similar in concept to how a submarine hides in the background noise of the ocean. But—like all stealth aircraft—it will not be invisible. Stealth is not a cloak of invisibility, after all. Stealth technology simply delays detection and tracking.

While the Air Force’s rendering of the B-21 gives us some clues as to the configuration of the new aircraft, most of its other parameters remain unknown. The B-21’s size and payload will largely be determined by whatever propulsion system is readily available to power it. Given that the LRS-B is slated to enter into service in the mid-2020s, the aircraft will necessarily have to use an existing engine design. Moreover, that engine must have a profile conducive to a stealth aircraft.

That would almost certainly rule out a commercial airliner engine derivative with a large bypass—such an engine would have an extremely large diameter even if it is highly efficient.

A more likely choice is a derivative of an existing military engine that is already in production. Possible choices could include unaugmented derivatives of the F-15 and F-16’s Pratt & Whitney F100 or General Electric F110. The F110, though an aged design, would give the LRS-B commonality with the Rockwell International B-1 Lancer and Northrop B-2 Spirit, both of which use engines from the same lineage. The B-1’s F101 was derived into the F110, which in turn was derived into the B-2’s F118 motors.

An F110 derivative does have its advantages, but the most likely candidate to power the LRS-B is an unaugmented version of the Pratt & Whitney F135, which in its current state offers roughly 28,000lbs of dry thrust. With some tweaks, such as an increased bypass ratio, a version of the F135 could probably produce more than 30,000lbs of thrust while potentially increasing fuel efficiency. With two such engines, an LRS-B would have less than the roughly 70,000lbs of thrust available to the B-2, but there are indications that the B-21 is smaller than the Spirit.

While the LRS-B might be provisioned to accommodate whatever engine ultimately comes to fruition from the Air Force’s adaptive-cycle engine program—variously called ADVENT, AETD and AETP—if the service is serious about an initial operational capability date around 2025, the new bomber will necessarily use an existing propulsion plant. It takes a long time and large sums of money to develop a new turbine engine. It’s also not an endeavor without risk—look no further than China’s frustrated efforts to develop an indigenous jet engine.

If one accepts the premise that the B-21 will be powered by twin unaugmented F135 engines, one can then assume that the new bomber will be larger than a Boeing F-15E Strike Eagle or General Dynamics F-111 but smaller than the B-1 or B-2. Given the types of threats from low frequency radars that are projected to be out there in the future and the limitations of current low observables materials, B-21’s subsonic flying wing design will be large enough to counter low frequency radars.

A tactical fighter-sized stealth aircraft must be optimized to defeat higher-frequency bands such the C, X and Ku bands as a simple matter of physics, but a strategic bomber like the B-2 or LRS-B can be larger to counter lower frequency radars. There is a “step change” in a stealth aircraft’s signature once the frequency wavelength exceeds a certain threshold and causes a resonant effect. Typically, that resonance occurs when a feature on an aircraft—such as a tail-fin—is less than eight times the size of a particular frequency wavelength. That means a bomber like the B-21 has to have allowances for two feet or more of radar absorbent material coatings on every surface or the designers are forced to make trades as to which frequency bands they optimize the aircraft to operate in. As such, to defeat low frequency radars operating in the L, UHF and potentially the VHF bands (this is easier said than done—and could in fact be impossible), a flying wing design is in effect, mandatory.

There are also indications that the Air Force is planning on building significant electronic attack capability into the B-21 airframe (and the LRS family). Electronic attack capability is necessary to counter low frequency radars operating in the VHF band, which are nearly impossible to defeat with airframe shape and low observable materials alone. The fact is that despite the Air Force’s public narrative that aircraft like the F-35 can go into a high threat zone alone and unafraid, the service’s own experts at the Air Force Warfare Center recognize the value of jamming. Stealth and electronic attack always have a synergistic relationship because detection is about the signal to noise ratio. Low observables reduce the signal, while electronic attack increases the noise.

“An improvement would be to include that presumably these platforms would be used in coordination with other platforms and weaponry so as to increase the noise from which to hide within,” one Air Force official with stealth aircraft experience told me. “Who wants to sort through a pile of hay for a needle when there are plenty of obvious needles that one should concern themselves with outside of the haystack?”

If the LRS-B is somewhat smaller than the B-2, the designers have to pick between range and payload. Former Air Combat Command commander Gen. William Fraser, a former B-52 pilot, told me few years ago when the program was in its infancy that “a combat radius of between 2,000 and 2,500 nautical miles is sufficient, which equals a 4,000-5,000 nautical mile range. All points on earth are within about 1,800 nautical miles from the closest body of water.” Thus, one can assume that the LRS-B will have at least that much range with whatever space leftover being dedicated to its payload. The LRS-B doesn’t necessarily need to carry the same amount of weaponry as the B-2, it just needs to carry the biggest available weapon—maybe just one GBU-57A/B Massive Ordnance Penetrator (MOP) instead of two.

In terms of avionics, the Air Force appears to be doing something smart. The aircraft will apparently use an open architecture computer system, which means that the LRS-B won’t be hamstrung with antiquated avionics and ponderous processes to integrate new weapons and hardware—like what happened with the Lockheed Martin F-22, for example. The aircraft will also be nuclear-capable from the get go, though it won’t be certified to perform that mission until later. That’s not surprising—and had been reported as early as 2011 during Gen. Norton Schwartz’s tenure as Air Force chief of staff. The service also plans for the LRS-B to be optionally manned, however the chances of operating a $550 million aircraft without a pilot onboard are laughably small.

The bottom line is that the LRS-B is shaping up to be exactly what it was expected it to be.

Viv S
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Re: Stealth in military aviation, pros and cons

Postby Viv S » 04 Sep 2016 21:41

Interesting topic. Let me just add a couple of points.

shiv wrote:Stealth and top class aerodynamic performance do not sit well together. Stealth requires features that reduce agility and aerodynamic performance and this can be countered by thrust vectoring, very efficient engines and fly-by-wire as was done in the F-22. Stealth also has the reputation of being maintenance intensive where the skin surface has to be kept free from dents, dirt and artefacts that reduce stealth. We have also discussed time and again about how internal weapons bays reduce payload carrying capacity. External carriage reduces stealth.


FLIGHT PERFORMANCE

F-22 - Well known.
PAK FA - Superlative.

F-35 - Compromised design. Or is it?

Lets be honest. The real debate here with regard to 'aerodynamic performance' is wrt to the F-35's reputation for mediocrity in that sphere. So lets examine the facts


Angle-of-attack limit: 50 degrees

Acceleration/Climb rate:

The engine has a lot of thrust. It’s been fun to outrun the F-16 (chase aircraft). They can’t keep up. If we go to full military power the F-16 has to go to afterburner to keep up. - Lt. Col. Hank Griffiths

Cruise speed/altitude:

With the F-35, we get more of all this, compared to what we are used to today. To discover how much more there was a pleasant surprise for me. In full war equipment F-35 effortlessly operates 10,000 to 15,000 feet higher than our F-16 manages, without using afterburner. The speed in 'cruise' is 50 to 80 knots higher. In F-16 I have to use afterburner and take running speed before a missile shot. F-35 "cruiser" both faster and higher. Therefore, I am ready to shoot far anytime. - Major Morten "Dolby" Hanche, Royal Norwegian Air Force

Turn Rate:

The F-16 has a superior sustained turn rate but the F-35's better ITR allows for better nose pointing during WVR combat. Ref:

The F-35 in a dogfight – what have I learned so far?

How Pilots Rate Fighter Jet Maneuverability

Even pre-IOC, this jet has exceeded pilot expectations for dissimilar combat. (It is) G-limited now, but even with that, the pedal turns are incredible and deliver a constant 28 degrees/second. When they open up the CLAW, and remove the (7) G-restrictions, this jet will be eye watering. - Heritage Foundation report (Surveyed 31 pilots transitioning to the F-35 from the F-15C, F-15E and F-16. The responses were eye opening.)

From an airpower demonstration event in Netherlands last month -





MAINTENANCE

The B-2's require a controlled environment (AC hangars and the like). The F-22's stealth is quite maintenance intensive.

The F-35 in contrast features new gen RAM that's supposedly 'baked' into the airframe and very maintenance friendly.


When the F-22 or the B-2 or the old F-17 fly their radar-absorbing skin, it's much more fragile and it takes a great deal of maintenance. The skin for the F-35 is way ahead of that. You don't have to park these aircraft in hangars and you could even try and take your heel and dig it into the skin of the F-35 and it won't harm the plane. - John Venable

Venable said he walked on an F-35A wings in his street shoes, and it didn’t harm the protective coating that helps provide the plane’s stealth. He could never do that on an F-22, which is known for its sensitive coating. The tougher stealth layer will allow it to be stationed in more austere settings in harsher environments.

“You can park them out in the sun in the open. … Now you’re starting to talk about a real fighter that has the real potential to do what you need to do in a real-world environment,” Venable said.
(link)


Developments that are now being carried over to the older F-22 -F-35 Stealth Coatings Applied to F-22

[The F-35 program] had some more robust materials that were more durable and we were able to pull those back on to the F-22. So our system is better, and the life-cycle cost of the F-22 is reduced."


RESULTS FROM COMBAT EXERCISES

F-22:

In Alaska, the F-22 achieved an unprecedented 144:0 kill ratio in the first week of Northern Edge. "In the first week of the fight, the preponderance of engagements were beyond visual range. In the second week they got into the merge and took a couple of shots," says Lawson, pointing out that the pilots averaged less than 100h on the aircraft. The final tally was 80:1.

Northern Edge included an air-to-air mission involving a "blue" team of 24 F-15Cs, eight F-22s and two F-15Es against 40 F-16s and F/A-18s that were allowed to regenerate to produce a total "red" air force of 103 aircraft.

The USAF says the blue team was able to achieve an 83:1 kill ratio, losing one F-15. Over the two-week exercise, the F-22 accounted for 30% of the blue force and 49% of kills.


http://www.flightglobal.com/articles/20 ... -f-22.html

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Inside the War Games for U.S. Air Force Fighter Pilots

Brenton (call sign "Gripper") has flown the F-16 for 20 years and has close to 4000 hours, including 750 hours of combat. He is also a former Weapons School instructor pilot at Nellis, the same program in which the 174th today is testing its mettle against the Raptor. He doesn't like to lose, but against the F-22 he has little choice. "Fighter pilots are competitive by nature. When the F-22 first became operational, most F-16 and F-15 pilots relished the challenge of going up against it," he says. "I know I did. That is, until I actually did it and discovered how humbling an experience it really was."

No U.S. airplane—or any other in the world—can match the F-22 in a dogfight during combat training. To get experience in realistic battle conditions, Raptor pilots—always the Blue Team— are training with U.S. pilots who serve as adversaries, or "Red Teams." Last week, Raptor pilots finished training against Navy F-15s and F/A-18 Super Hornets in Japan. From February through April, Nellis hosts F-22s at the 2009 Red Flag wargames, a six-week, multinational training exercise held at Eielson Air Force Base in Alaska and at Nellis.

F-22s dominate at Red Flag as well. Red Teams flying F-16s and F-15s take them on. Those who train to be the adversaries at Red Flag belong to the 64th and 65th Aggressor squadrons. These seasoned Red Team veterans find it frustrating to fight what they can't see. "Aggressor pilots are not typical Air Force line units. They tend to have much more experience," says Mike Estrada, a spokesman at the air base. "And I can tell you that our Aggressor pilots are getting very tired of always getting shot down by the F-22."

Learning Potential of a One-Sided Fight

"My F-16 is still a formidable weapons system in its own right. But it is not even in the same league as an F-22," Brenton says. "Technology keeps the F-22 a virtually undetectable and untouchable regime. It is fair to say that unless an F-22 driver makes a mistake, or has a critical system failure, I will always lose a fight against him. That is a good thing. As a nation, we want it this way. We also want him to be able to handle two, six or eight of us completely on his own."

Into the Fight

Simulated gun and missile shots are tracked by the controllers on the ground. When a target is killed, the deceased pilot receives a radio call telling him that he is dead. The pilot will often be sent to a location that simulates an enemy alert airfield, where he is "regenerated," simulating that the enemy has launched another aircraft. (The trainees go back to the base and land if they are killed.) When it comes to fighting Raptors, regeneration is an expected occurrence for WIC Red Teams. "We do everything we can to try and challenge them: We increase our total numbers, we regenerate, we electronically jam the environment. And we die," Brenton says. "We die wholesale. We are kill-removed repeatedly and then regenerated, and then we are killed again. The process would be demoralizing if we didn't maintain proper perspective. This is our job while we are here. What motivates us is the fact that we are training our brethren—and they are damn good at what they do."


___________________________________________________________________


F-35:

The F-35 is so stealthy, it produced training challenges, pilot says

During a recent exercise at Mountain Home Air Force Base, Idaho, F-35 squadrons wanted to practice evading surface-to-air threats. There was just one problem: No one on the ground could track the plane. “If they never saw us, they couldn’t target us,” said Lt. Col. George Watkins, the commander of the 34th Fighter Squadron at Hill Air Force Base, Utah.

The F-35s resorted to flipping on their transponders, used for FAA identification, so that simulated anti-air weapons could track the planes, Watkins said. “We basically told them where we were at and said, ‘Hey, try to shoot at us,’ ” he said, adding that without the transponders on, “most likely we would not have suffered a single loss from any SAM threats while we were training at Mountain Home.”
.
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“When we go to train, it’s really an unfair fight for the guys who are simulating the adversaries,” Watkins continued. “We’ve been amazed by what we can do when we go up against fourth-gen adversaries in our training environment, in the air and on the ground.”

Watkins said he can take four F-35s and “be everywhere and nowhere at the same time because we can cover so much ground with our sensors, so much ground and so much airspace. And the F-15s or F-16s, or whoever is simulating an adversary or red air threat, they have no idea where we’re at and they can’t see us and they can’t target us.”

“That’s a pretty awesome feeling when you’re going out to train for combat,” Watkins concluded, "to know that your pilots are in an unfair fight.”


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[url==http://aviationweek.com/defense/f-35-unscathed-hostile-fire-green-flag]F-35 Unscathed by Hostile Fire in Green Flag[/url]

Not a single F-35 was “shot down” during the joint-force Green Flag exercises testing the jet and its pilots’ prowess operating it in a contested air-support role in the Western U.S. this month, according to U.S. Air Force Lt. Col. Cameron Dadgar, head of the exercise and leader of the 549th Combat Training Sqdn. at Nellis AFB, Nevada.

This is notable because A-10s and F-16s were defeated in the same conditions, operating in an environment with hostile aircraft and surface-to-air missiles, he said.


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Lockheed F-35 jets ace exercises as U.S. readies for combat use

Air Force Lieutenant General Chris Bogdan, who runs the F-35 program for the Pentagon, said the jets' appearances at the UK air shows and other milestones were helping demonstrate to critics that the F-35 was more than "a paper airplane."

He said the world's largest weapons program was still working through some software glitches, but was "on the right track" to complete its development program in late 2017. He said it was likely take a real combat deployment or deterrence mission to dispel negative impressions after years of bad news.

"When we actually have the airplane out there ... and people realize how much of a leap in technology it is, then and only then will people start to realize that all the time and energy put into it is really worth it," Bogdan said in an interview.

He said the jets' performance in exercises like Red Flag showed that onboard radar sensors and electronic warfare equipment would give them a huge edge in future wars. While one-third to one-half of other aircraft would routinely be "killed" during tough exercises, no F-35s had been downed, he said.


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Right now we're seeing no problems with that airplane. What we're seeing is high readiness rates and incredible capability. We just ran a WTI drill, a normal scenario we would have with our legacy aircraft out there. I was the CO of that weapons school. Generally about half the aircraft that go across into the high end threat... Prowlers, Hornets, Harriers and generally about half of the 30 airplanes don't make it through. The F-35 [got a] 24-0 kill ratio and killed all the targets. It was like Jurassic Park.. watching a velociraptor. It kills everything. It does really well so we can't get that aircraft fast enough into the fleet.

- Lt. Gen. Jon M. Davis, Deputy Commandant for Aviation, U.S. Marine Corps

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F-35B Tactics Evolving As Pilots’ Understanding Of Technology Matures

Last summer, as a last step before recommending an IOC declaration, Davis tasked the first F-35B squadron with completing an operational readiness inspection – a test event borrowed from the Brits, he said. As part of the test, Marine Fighter Attack Squadron (VMFA) 121 performed an armed reconnaissance mission that can sometimes take AV-8B Harrier and F-18 Hornet pilots all day to complete. “These guys went out there and they found all the targets very quickly and killed all the targets,” he said, noting the early proficiency of the squadron. “Most importantly, … we put a radar [surface-to-air missile] out in the objective area. In the old days we’d have to go take care of the radar SAM, get somebody in to go take care of that because you don’t do armed reconnaissance, which is patrolling for targets out there, unless you’ve got a permissive threat environment and you beat that threat. These guys went out with the SAM in the area and did that and they killed the SAM.” Fast forward a year, he said, and the squadron has gone from proficient to innovative. Davis brought Marine Corps Commandant Gen. Robert Neller to meet the pilots and learn about the planes and tactics. During the visit, the squadron was assigned two drills.

The first was done with fewer planes than Davis thought was needed, but otherwise went according to plan. He said the pilots were given a scenario that was “very high-end, off the ship, go into the jaws of death, double-digit SAMs, fighter threat, and go after a very strategic target on the ground. I watched them do it as a foursome, which normally I would say it would be 13 or 14 airplanes normally, what I would do as [commanding officer] of the weapons school, which I was. … They killed the fighters, they killed the SAMs, they killed the target, they came home. “What was most interesting to be was not what they did but how they did it. It was very much the maturation of the pilots and how they’re flying this airplane, how they’re using information, communicating with each other, sharing information,” he continued. “It was more like watching a pack of dogs go after something. And it was force-on-force, it wasn’t scripted,” so their success – particularly with so few aircraft – was far from guaranteed.

The second drill, though, did not go as planned – in the best possible way, Davis said. The planes were to fly a close-air support mission through clouds at 1,000 feet, with the planes in the 3F configuration that allows for pylons to externally carry 18,000 pounds of bombs. “I’m out there, the commandant of the Marine Corps is out there, I want to impress the commandant,” Davis said. “This first scenario was awesome, and then right before the second scenario I said, are we ready to go? And this young major comes up … he goes, ‘we’re not going to do exactly what you want us to do.’ I’m like [eyes grow wide]. “Because we didn’t think the tasking was challenging enough. So we’ve got two that are slick and two that are loaded up as bomb trucks. We can do the job sir, don’t worry.’” So two planes forfeited their external carry capacity in exchange for stealth, and “it was a work of art,” Davis said. The planes hit all their targets in five and a half minutes, with the four planes passing images through the clouds and successfully taking out the missile threat early on. “I just watched, I’m like, that’s not how my brain works, but that is the way their brains are working,” he said. “Gen.(Charles) Krulak, who I used to work for, said ‘you don’t man the equipment, you equip the man,’ so we’re equipping these young Marines, this generation that doesn’t know any bounds for latitude for technology, and they’re leveraging this technology and doing great things.”



Finally I want to add the fact that many countries on the world, faced with extreme stealth have invested in technology to detect stealthy aircraft. To my knowledge these include IR sensors and appropriate radars. Some of these radars are very high powered - the idea being that even small radar returns will come back stronger. Of course there are arguments against the effectiveness of all this, but I am not going into that - will leave it for others.

True. But also keep in mind that these countries investing in means to detect stealth aircraft are also investing in stealth aircraft of their own (PAK FA, J-20, J-31).

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Re: Stealth in military aviation, pros and cons

Postby darshhan » 04 Sep 2016 23:51

Viv S ji, this is not F-35 Marketing thread.

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Re: Stealth in military aviation, pros and cons

Postby shiv » 05 Sep 2016 07:30

Viv S wrote:
shiv wrote:Stealth and top class aerodynamic performance do not sit well together. Stealth requires features that reduce agility and aerodynamic performance and this can be countered by thrust vectoring, very efficient engines and fly-by-wire as was done in the F-22. Stealth also has the reputation of being maintenance intensive where the skin surface has to be kept free from dents, dirt and artefacts that reduce stealth. We have also discussed time and again about how internal weapons bays reduce payload carrying capacity. External carriage reduces stealth.


FLIGHT PERFORMANCE

F-22 - Well known.
PAK FA - Superlative.

Both have thrust vectoring, so the "problem" with stealth remains. It you don't have thrust vectoring (TV) your stealthy fighter will manoeuvre like a transport plane.

Given that most nations in the world do not even make engines let alone engines with TV, the future of stealth in a whole lot of countries is going to remain a toss up between
    Full stealth + TV
    Full stealth without TV or
    Half (or less) stealth

Personally I would be wary of mentioning F-35 and J-20 in the same breath. The J-20s design, with all those flat control surfaces and burning hot Al-31 in its ass is far less stealthy than the F-35 and it depends more on frontal stealth - so J-20 is "half stealth"

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Re: Stealth in military aviation, pros and cons

Postby TSJones » 05 Sep 2016 08:45

Both have thrust vectoring, so the "problem" with stealth remains. It you don't have thrust vectoring (TV) your stealthy fighter will manoeuvre like a transport plane.


Oh my gosh! Not a transport plane! :D so, stealth needs thrust vectoring in order to.....?

from the aviationist......

https://theaviationist.com/2013/02/21/r ... yphoon-us/

“Raptor’s thrust vectoring not essential” Eurofighter pilot says in last chapter of the F-22 vs Typhoon saga

Anyway, here’s what he wrote to us:

We have all been around long enough to recognize there is not a single sensor able to turn the night into day, nor a unique aerodynamic design feature capable of ensuring by itself air dominance if implemented.

The effectiveness of an air superiority fighter relies on the successful combination of a range of design elements including thrust-to-weight ratio, wing loading, avionics and weapons integration. Furthermore, : appropriate tactics and valuable aircrew training must be developed to exploit the full potential of the weapon system.

Typically, when time comes to decide how to achieve the required “nose pointing capability” for high thrust-to-weight ratio airplanes three solutions are on the table:

– extremely high short term sustained Angle of Attack values (characteristic of twin tailed airplanes);
– High Off-Bore-Sight Weapons, preferably supported by Helmet Cueing;
– Thrust Vectoring.

Thrust Vectoring is one of the design elements that can contribute to create a certain advantage during close air combat by generating impressive pitch and yaw rates, but only in a limited portion of the flight envelope at velocities well below “corner speed”.

However, Thrust Vectoring can also transform in a few seconds an energy fighter in a piece of metal literally falling off the sky, making it an easy prey for those who have been able to conserve their energy.

Moreover, Thrust Vector operation requires the pilot to “create the opportunity” for its usage, spending valuable time in manoeuvring the aircraft to achieve a suitable condition and managing the activation of the Thrust Vector Control.

If you are “defensive” and your aircraft has Thrust Vectoring, you can possibly outturn your enemy, but that most likely won’t prove to be a great idea: an energy fighter like the Typhoon will conveniently “use the vertical” to retain energy and aggressively reposition for a missile or gun shot. Also the subsequent acceleration will be extremely time (and fuel) consuming, giving your opponent the opportunity to tail chase you for ever, exploiting all its short range weapon array.

If you are “neutral”, when typically vertical, rolling and flat scissors would accompany the progressive energy decay, similarly performing machines would remain closely entangled, negating the opportunity for Thrust Vector activation.

If you are “offensive”, probably stuck in a never ending “rate fight”, Thrust Vector could provide the opportunity for a couple of shots in close sequence. Make sure nobody is coming to you from the “support structure”, otherwise that could be also your last move.

Talking of twin tailed aircraft, Angles of Attack in excess of 30-35 degrees are capable of creating drag conditions unsustainable no matter the engine/airframe matching, and developing energy decays intrusive of the tactical flying but also of the flight control system protections. Roll rates would also deteriorate at the higher values of AoA and target tracking ability would quickly decay.

Eurofighter has decided to develop for the Typhoon High Off-Bore-Sight Weapons, supported by Helmet Cueing, to retain energy and target tracking ability while manoeuvring WVR (Within Visual Range) at relatively high but sustainable Angles of Attack. For those who may require some additional AoA, the “Strakes” package is progressing well and soon it will be offered to Typhoon’s Customers. Nevertheless, Strakes is not purely about extreme AoA, but also suitable Roll Rates and manageble energy characteristics. Because in the European way of doing things, an all round balanced solution counts more than a single eye opening performance.

It is a fact that against Eastern produced fighters provided with Thrust Vectoring, throughout the years the Typhoon has showed an embarasing (for them) kill-to-loss ratio.

It is a fact that after some initial encounters between the Raptor and the Typhoon, the situation appears of absolute equity. Too early to say if it is the Helmet Cueing or the Thrust Vector, or how much tactics and training are a player in all this. For sure, we are facing two impressively capable machines.

The typical answer to any critics to the F-22 air dominance is: “since it is stealthy, you should not even consider the possibility of a close encounter with another jet.”

Even if this can be true, the risk of coming to close range is still high. At a distance of about 50 km the Typhoon IRST (Infra-Red Search and Track) system could be capable to find even a stealthy plane “especially if it is large and hot, like the F-22″ as a Eurofighter pilot once said.

Furthermore, Raptors are not always stealthy as one might believe: for instance, when they carry external store, rejoin with tankers or talk on the radio (secure or unsecure ones) they become more vulnerable to detection.

But this is another story, that we will discuss in the near future…


again I must insist that these planes are weapons systems,

topics such as thrust vectoring or stealth are just part of the picture. there are many other factors that can also bring success. the entire weapons platform must be considered. you cannot use them irrespective of their overall limitations or they can be defeated under certain given circumstances. the fog of war is a harsh mistress.........(war's a cruel b**tch)

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Re: Stealth in military aviation, pros and cons

Postby shiv » 05 Sep 2016 11:29

TSJones wrote:
Both have thrust vectoring, so the "problem" with stealth remains. It you don't have thrust vectoring (TV) your stealthy fighter will manoeuvre like a transport plane.


Oh my gosh! Not a transport plane! :D so, stealth needs thrust vectoring in order to.....?

Full, all aspect stealth could escape without thrust vectoring or spectacular agility. It is the half-assed "only frontal aspect stealth" fighters, of which the US has exactly none, that need to do some kind of toss up between stealth and agility.

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Re: Stealth in military aviation, pros and cons

Postby shiv » 05 Sep 2016 11:32

What is stealthy and what is unstealthy about this plane
Image

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Re: Stealth in military aviation, pros and cons

Postby shiv » 07 Sep 2016 07:37

Cross post
http://www.dailyo.in/politics/j-20-stea ... 12782.html
Does India need to worry about Chinese stealth fighter J-20?

AVM Manmohan Bahadur

News reports have appeared in the Indian media about the presence of the Chinese J-20 stealth fighter at Daocheng Yading in Tibet, the highest civilian airport in the world.

One article carries a photograph of a J-20 on a rain-swept tarmac, with the aircraft draped in a camouflage net - desert camouflage pattern!

Surprisingly, there are no chocks on wheels (to stop the aircraft from rolling) and the photograph shows a small hill in the background - no identifiable features of the airport are visible.

The photographs, as per the article, appeared in China on the social micro blogging site Weibo and on two websites just "days before PM Narendra Modi travels to China for G-20" and "days after China warned India against deploying BrahMos missile along the Himalayas".

A news brief was also carried as a lead item by its national television arm and the two conveyed an alarmist view of an event that otherwise is a normal milestone in the development cycle of a new aeroplane.

Unfortunately, this view has been generated by many other media articles too, one of which stated that China has moved stealth fighter into Tibet! It is time a professional assessment of the "sighting" of the J-20 in Tibet is undertaken.

That the J-20 programme has entered the low rate of initial production has been widely reported in the press, both Chinese and Western.

After the first prototype flew on January 11, 2011, seven more prototypes have been built for various phases of testing.

The test flying has proceeded at a very fast pace such that the first squadron would reportedly get established in 2017 with aircraft having initial operational clearance.

Many photographs of the aircraft have also appeared, but surprisingly there have been no images of two J-20s flying together or any armament being fired (only images of open weapons bay are available).

The deductions with this type of background information are:

1. The prototype testing of the J-20 is still work in progress.

2. Even though the first squadron may get raised by 2017, the operational capability would not be that of a fully operational squadron as some clearances would come only after all aspects of the flight envelope are explored.

3. The squadron would, in parallel, work up the standard operating procedures and train pilots in basic handling and procedures of the J-20.

4. The aircraft is powered by Russian engines which do not give it super cruise capability (speed more than the speed of sound with no afterburner).

Thus, the J-20 is not a true fifth generation fighter at present. The super cruise capability may come once the indigenous WS-15 engine gets cleared - this is still some distance away as the Chinese are facing problems of reliability in indigenous power plants.

5. It is a well-known fact that the paint work and skin finish play an important role in making an aircraft stealthy; hence, the very casual way in which the camouflage net has been draped on the aircraft in the photo, with loose flapping strings, shows that stealth is not being given its due, despite the hype that surrounds it.

So, is the aircraft really stealthy, for if it was then the net would not have been draped the way it is.

6. That the aircraft landed and took off from an airfield at 14,000ft is indeed creditable (considering that the photo is genuine).

But, this is just half the story. What would be operationally relevant is the information about the payload it carried and the ambient temperatures it operated in.

So, what was the J-20 doing in the high altitude airfield?

The answer is, just what the Indian Tejas was doing at the high altitude airfield at Leh some months back - these aircrafts have operated from high altitude airfields as part of their hot and high prototype testing, which are mandatory as part of clearance of their flight envelope.

What the photo does confirm is that the capability to operate from Tibet may be part of the task for the J-20.

Many more visits to Tibet would be required to test out the aircraft in cold weather conditions, especially an engine start after an overnight "cold soak" in the open.

This test is indeed critical, besides many more to check out its systems, especially the avionics and radar, in the extreme cold conditions that prevail in Tibet.

The appearance, thus, of the J-20 in Tibet being linked to either the visit of PM Modi to China or the decision to place BrahMos missiles on India's borders is incorrect.

It is not "signalling" being done for geopolitical reasons but just part of flight testing that any aviation system goes through.

However, the message that does come through to India is that in some years to come, the Indian Air Force must prepare for the presence of a fifth generation fighter that can operate from high altitude air fields in Tibet.

It can only get interesting from here - the last word on stealth in Tibet has not been said yet.

(Courtesy of Mail Today.)



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Re: Stealth in military aviation, pros and cons

Postby Mihir » 08 Sep 2016 00:30

This graphic is instructive.

Image

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Re: Stealth in military aviation, pros and cons

Postby Indranil » 08 Sep 2016 00:42

If it was that simple, the whole of USAF should just be a few B-2 bombers.

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Re: Stealth in military aviation, pros and cons

Postby Mihir » 08 Sep 2016 01:14

Hence instructive and not illustrative. :)

Obviously there's a myriad of mission types; very few of which need long-range bombers to carry out. What the graphic shows is that using stealthy aircraft with precision munitions cuts down on the support assets that need to be deployed in order to enable a strike package to get through.

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Re: Stealth in military aviation, pros and cons

Postby Mihir » 08 Sep 2016 01:16

Shiv, the F-35 does not have thrust vectoring. The nozzle remains fixed except when the plane is landing.

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Re: Stealth in military aviation, pros and cons

Postby shiv » 08 Sep 2016 06:19

Mihir wrote:Shiv, the F-35 does not have thrust vectoring. The nozzle remains fixed except when the plane is landing.

I know. Even that moving nozzle is only F-35B with Rolls Royce engines

I repeat that the design requirements for stealth are not great for agility so if anyone wants stealth and agility thrust vectoring is necessary. The F-35 has done away with agility as something that is not required because it has all aspect stealth, sensor fusion and BVR capablity so the agility bit has been declared redundant.

Too much time is spent talking about the F-22, F-35, F-117 and B-2. Americans fill the media with their stuff. But the future of stealth will also involve other air forces and what they can do. 80% of air forces will not have the F-35 or that level of technology. So they are likely to have a mix of semi stealthy aircraft or unstealthy ones with some lipstick on pig style stealthification. Or else nations may choose missiles as a route that bypasses the need for manned aircraft (like NoKo/shitistan)

So the future of stealth in military aviation is not jut F22, 35 and B-2, but what other air forces to to either keep up or compensate for the lack of US level stealth aircraft

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Re: Stealth in military aviation, pros and cons

Postby NRao » 08 Sep 2016 06:55

IMHO, it would help immensely, if we replace "stealth" with "Low Observable (LO)".

From the above discussions, it appears the topic is relegated to air crafts only (name of this thread) Point being "stealth" has been traced to the adoption of camouflage (by the British) as early as the 17th century. And, ducking under the radar coverage is also "stealth".

The idea behind "stealth" being postpone detection until it is too late. The best case, obviously, not be detected at all - which is actually not part of the game plan.

Detection is based on the entire spectrum: sound, light, radar, RF being the most prominent ones - there could be others.

On features, I would NOT compare between air crafts from various nations. Each AF would build a plane based on their comfort with their own philosophies. And, part of it will be defining what LO is. So, I fully expect the FGFA to be radically different than the PAK-FA, although both will fairly look alike.

Even that moving nozzle is only F-35B with Rolls Royce engines


PW.

I think RR is providing support within the UK, for the British F-35s.

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Re: Stealth in military aviation, pros and cons

Postby ArmenT » 08 Sep 2016 10:49

Speaking of stealth, I have a copy of Lockheed's Ben Rich's book and he mentioned a few pros/cons of stealth and the compromises that they made, at least as pertaining to the F-117.

* While the F-117 was precisely machined so there were no protruding edges to reflect radar, there was also some kind of paste that needed to be applied to the moving joints (canopy, bomb doors etc.) to seal them up and this needed to be done for every flight, which increased the turn around time of the aircraft.

* All that stealth cost a lot of money.

* The amount of radar energy reflected back is not the same at all angles. The aircraft is optimized to reflect back minimum radar energy when the transmitter is directly in front. It was not completely invisible, but the idea was that it could sneak into an area and by the time it was detected, it was hopefully close enough to the target that the enemy can't react fast enough to do anything about it. This is why missions were planned to take a route which would present the smallest radar profile to all the enemy's known radar sites.

* The reason that the F-117 is all flat surfaces whereas the B-2 is curvaceous has to do with the computers available at the time that the F-117 was designed in the 70s. The calculations were done for 2D surfaces and flat planes because at that time, computers weren't powerful enough in storage and memory capacity to allow for 3D designs or curvy shapes, which meant huge numbers of additional calculations. The B-2 was designed much later when computing technology had improved.

* F-117 could not go supersonic. Doing so would have meant ejecting hot gases into the air which would leave a large IR signature. In fact, in order to reduce the IR signature, they would vent the hot gases through heat dissipating tiles and push it out of the aircraft on the upper surface.

* Note that while the F-117 was originally designated to be a fighter (which is why the name starts with F), it doesn't maneuver all that well, which is why it was actually used as a bomber and only at night time too so that it could not be easily seen, because they did not want it ever being in a turning dogfight scenario, which was its major weakness.

* Fuel efficiency was not that good either, they needed to have aerial tankers to top them up on flights.

* On the other hand, the stealth features succeeded beyond expectations during Gulf War - I. The F-117 was the only aircraft designated to attack Baghdad, as it was one of the most heavily defended cities in the world when it came to number of AA guns and missiles.

* One pilot over Baghdad reported that when he dropped his load, his door malfunctioned for a bit and wouldn't close and his AA warning lights went off immediately as a bunch of radars picked him up. He managed to use the manual override to pull the door back and let out a sigh of relief as an incoming missile lost his trail

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Re: Stealth in military aviation, pros and cons

Postby JayS » 08 Sep 2016 14:05

NRao wrote:
Even that moving nozzle is only F-35B with Rolls Royce engines


PW.

I think RR is providing support within the UK, for the British F-35s.

RR supplies the lift Fan system for that. Engine is PW F135 of coarse. And for all VTOL F35s not just British.

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 09 Sep 2016 04:35

The US was first off the mark in demonstrating the use of stealth. The "Blackbird" was noisy and hot, but it was supersonic and the black was to keep it stealthy and it set set the stage for later stealth aircraft. The F-117 was, to my knowledge, spectacular in Bosnia as well as the first Iraq war, achieving amazing breakthroughs via SEAD. This was followed by the B-2. The US followed this up with the ostensibly superlative F-22 with all aspect stealth. And now we have the F-35, apparently also very stealthy.

All those aircraft used different degrees of stealth, against different target emitters, depending upon the technology of the time allowing for other design trades. SR-71 reduced the RCS just enough for the aircraft to be hard to distinguish from other aircraft while flying similar profiles (The Canadians fell for this on a few occasions). The F-117 was an early attempt and was born out of the hopeless diamond configuration.

The B-2 was the first aircraft designed around broadband stealth requirements no doubt because of its strategic mission requirements. F-22 and F-35 were designed to break kill chains while also meeting other traditional fighter-aircraft performance metrics in line with the aircraft and missions they were intended to replace and perform.

Stealth and top class aerodynamic performance do not sit well together. Stealth requires features that reduce agility and aerodynamic performance and this can be countered by thrust vectoring, very efficient engines and fly-by-wire as was done in the F-22.


This is highly debatable. One could argue that giving RCS targets for designers forces them to make design trades but that could be said of a lot of things. Asking the aircraft to go Mach 2+ does the same, as does asking it to go a set distance. Take any design and look at the trades and one could argue that reducing certain other aspects could result in better maneuverability with or w/o TVC. Remove the Mach 2 requirement from 4th generation aircraft and you could probably tinker around with the configuration and get better performance elsewhere. Similarly, play around with range and fuel requirements and you can end up with better performance. Within those design constraints however there is plenty of room to get desired levels of performance.

On the ATF for example the USAF removed the requirement for TVC after exploring it in the pre-development phase (Various programs using 4th generation aircraft). The designers therefore had a choice of showing up without a need for such a capability and Northrop ditched TVC from their design but were still able to meet the performance requirements.

Similarly, as the ATF program boss mentions in his book, Lockheed faced a dilemma on whether to design the YF-22 to meet or exceed performance requirements with the aid of TVC or do so without it. In the end they designed their prototype to meet all performance requirements without the need for TVC even though their design had it. In a way the aircraft (YF22) was overdesigned as a hedge. This was done because LMA was unsure on how the USAF will respond to TV and that they may ask them to strike it off from the final proposal thereby putting them at a disadvantage if their proposal required it to meet its design requirements.

I don’t think anyone here would argue that the ATF requirements demanded relaxed performance. Supercruise was expected to be at or in excess of Mach 1.5, Sustained AOA at or in excess of 60 degrees, while sustained turn and G performance was to be comparable to the best aircraft in the USAF at the time. The design and performance requirements were relaxed to make the platform less risky and expensive post SU collapse that led to the peace dividend but the end result still continues to demonstrate extremely capable maneuverability at airshows, flown always by combat coded pilots and with a very strict requirements when it comes to the amount of fuel it carries (The USAF publishes its F-22A air-show profile requirements ).

One could argue that they achieved this with proper access to the right level of technology, as long as they did not go crazy with all aspect, broadband stealth which forces you to adopt a flying winged, cranked kite etc. like design profiles. That will probably happen with Next Gen. systems but would require supporting advances in other areas (propulsion, weapons, mission systems etc).

As I have mentioned elsewhere in the past, having access to an YF119/120 level of propulsion in the late 80’s and early 90s, allowed an ATF and through it Lockheed and Northrop to take a lot of design decisions in favor of lower RCS thresholds. The Chinese simply do not have this luxury even now so achieving F-22 like performance, or all aspect RCS would have been a challenge ultimately not a viable trade given their expected timeline for induction into service.

On the JSF, the requirements were relaxed for affordability giving the designers, a very large trade space. They wanted a single engine fighter, wanted a significantly higher mission radius (In excess of 1000 km) with a significant payload (2 x 2000 lb bombs and 2x AMRAAM’s) and all using internal fuel. They also wanted it to be significantly cheaper than the F-22A (less than half the APUC).This meant that they looked at the things that tend to drive costs, and framed performance requirements in order to best meet performance and cost curves.. With that program the attitude at least with the USAF was “ We do X missions with the F-16, and we have all this capability we developed for the ATF” – Get all that capability and advances in Low Observability, and mission systems incorporated within the current F-16 utilization patterns .

Think of the F-35A as stealthy F-16 that has solved some of the biggest shortcomings of the F-16 (due largely to its LWF legacy) with respect to its current utilization – i.e. Sensor size and internal fuel/range. Within those parameters they chose to keep the most advanced Mission systems requirements in tact and actually substantially built on what was achieved in multi-spectral sensor fusion, and big data on the ATF effort .

Out went the Mach 2 (+) top speed or Mach 1.5+ Supercruise requirement that the ATF was designed around, and this allowed them to add more composites and keep RCS requirements low. Similarly, they reduced Sustained AOA to 50 degrees (still considerably better than the F-15, 16 or 18) and demanded other performance similar to the F-16 or 18.

They could have asked for longer range, higher payload and better performance but what you would have ended up in would have been an F-22B or FB-22 like concept that could supercruise and had long range but would have been on the right side of the F-22 cost. The performance it has is a result of choices made during its conception, choices that would naturally come when you have to field a four digit sized fleet of it. Similar choices came about with the F-16 when it was inferior to the F-15 in many areas despite coming after it.

I guess what I’m getting at is that the F-35 is at par with the F-16 or F-18 when it comes to maneuverability NOT because it lacks TVC. It’s at par with them because that was what was demanded, allowing its designers to trade stuff away for other capability. One look at the vertical tail size of the F-22 and F-35 tells all that one needs to know.

Stealth also has the reputation of being maintenance intensive where the skin surface has to be kept free from dents, dirt and artefacts that reduce stealth. We have also discussed time and again about how internal weapons bays reduce payload carrying capacity. External carriage reduces stealth


That has historically been the case, although over the years this has been progressively reduced to a point where on the F-35, early experience both in utilization and during lifetime testing has shown the design to comply with RCS even with the routine dings, scuffs and abuse that these aircraft are subjected to.

See: https://i.imgsafe.org/1f4f06b97e.jpg

Finally I want to add the fact that many countries on the world, faced with extreme stealth have invested in technology to detect stealthy aircraft. To my knowledge these include IR sensors and appropriate radars. Some of these radars are very high powered - the idea being that even small radar returns will come back stronger. Of course there are arguments against the effectiveness of all this, but I am not going into that - will leave it for others.


IADS created a cost on an offensive operation that led those that wished to overcome it to invest in survivability across the spectrum. Similarly, increasing survivability imposes a cost on a defensive force that would not have existed in the absence of these survivability enhancing measures. In other words - TIC-TOCK.. Forcing your adversaries to make very serious investments in IADS takes away from their offensive capabilities just as ‘stealthifying’ your strike aircraft comes at a cost.

This means a hard look at the Electro Magnetic Spectrum, and developing strategies and capabilities to dominate it. Stealth is one of the most efficient ways to procure survivability against many elements within the EMS. Investing in Jamming is another way to do this.

What happens when F 22 attacking china is detected by old tech ground radar and china launches cheap UCAVs equiped with IRSTs in that location folloed by su 30mkk, now how many of these drones f22 can kill to stay stealthy and while it kills them it'll sure launch missiles/bullets making it unstealthy for those moments to be confronted with 30mkk.. usaf operates 600 f-15s? But they decided not to replace them with f 22 which needed 30 hrs maintenance for 1 hour flying. Stopped producing them at 181.


This has a lot of stuff in it that does not make sense if one goes into the weeds of how what you are proposing is tactically operationalized. Regarding your 1 hr vs 30 hrs claim, it would be wise to go into how O&S works and what these data mean.

While they decided to make cheaper stealthy f-16 replacement as F-35 which again ate up 1 trillion dollar


Do we really need to discuss this? Could you show where they have spent $ 1 Trillion dollars?
B-2 Bomber upto now was considered as ultimate stealth platform, now it is revealed that it is no more stealthyand to counter the low frequency radars that can detect and track tactical fighter-sized stealth aircraft they need B-21.


The B-2 first flew 27 years ago and as a design is probably 3+ decades old, and that includes many of its core technologies and capabilities. Survivability is not a constant, and designs do not last forever.

While the B-2 has seen tremendous gains in survivability thanks to its mission system modernization, and the application of better treatments to its OML, it will still suffer on account of being a late 70’s and early 80’s design. Over the next few decades, against the toughest of Air defenses, the B-2 will become more of a Stand Off platform and is therefore, getting a new weapon for that role (LRSO). It however as a design will still be able to penetrate many other air-defenses on account of its basic shape and mission systems.Not everyone will have S400+ everywhere hence the B-2 will be a viable penetrating aircraft for decades to come, just not against the highest of the threats. That coupled with the need to eventually replace the B-52 and the B-1’s means a new aircraft would be required. The USAF hasn’t had a new Bomber since the B-2 and eventually they would require something new if they want to maintain a viable and advanced bomber fleet – Hence the B-21.

I wouldn’t really like to waste a lot of time on a Dave Majumdar article.

usaf operates 600 f-15s? But they decided not to replace them with f 22 which needed 30 hrs maintenance for 1 hour flying. Stopped producing them at 181.


The USAF never intended to replace the Strike Eagle (F-15E) with the F-22 as no variant of the raptor can fit that role. The F-22A was/is an F-15C replacement. Therefore, you would need to slash quite a bit of aircraft from that F-15 count of 600. Towards the end of the F-22 production, the USAF's own TACAIR studies, followed by those of the CRS recommended an absolute minimum of 260 F-22's which they did not get. The overall demand with 'hedge' baked in was 380. With 181, this leaves approximately 200 aircraft deficit which would need to be filled by "something" with that something most likely being a mix of upgraded F-15C's and F-35A's dedicated to the Air to Air Mission. Over the next decade they'll probably increase the 'available' F-22A's by making the non combat coded aircraft, combat coded. I think thats a good couple of dozen aircraft

Needless to say we are going to be well into the latter half of the 2020's, and early 2030's before a near peer fields an equal number of competing 5th generation aircraft and given the F-35 delivery rate is already @ or more than 50 I don't think that worries them as much as getting a new aircraft by the early-mid 2030's to support the other long range fleet that they are developing does.

I repeat that the design requirements for stealth are not great for agility so if anyone wants stealth and agility thrust vectoring is necessary. The F-35 has done away with agility as something that is not required because it has all aspect stealth, sensor fusion and BVR capablity so the agility bit has been declared redundant.


The F-35 has not done away with agility. If that were the case it would not have been a 9G fighter, with 50 Sustained AOA requirement. Its just kept the bar for agility at par with the types it is replacing - the F-16 and F-18 whereas the F-22 improved it considerably from the previous gen. US designs.

As I have pointed out, within the performance trade space they have gone in and highlighted instantaneous turn rates, and High AOA more so than the sustained turn performance of the F-16 but there is academic work from the 80's and 90's illustrating how these metrics have come to be more important in a modern close in aerial combat, so it wasn't totally unexpected.

If performance were totally not a concern, they would have naturally designed this aircraft much differently, and it would probably have had a lower RCS, and been cheaper.
Last edited by brar_w on 09 Sep 2016 05:31, edited 5 times in total.

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 09 Sep 2016 04:36

One must remember stealth is a means to an end. The end being the ability to be survivable against an adversary armed to defeat you by denying access to certain areas and capabilities. Both Russia and China have seen what happened in the GW and Kosovo and have since then invested heavily in denying the US and its allies the use of their integrated strike-complexes, standoff weaponry and PGM’s. This they have done by distributing their Command and Control, by investing in long range air-defenses, long range fighters, kinetic and non kinetic anti_PGM effects, and long range weaponry specifically designed to go against the battle managers. They and others have seen what the second offset technologies have enabled, and have invested in counter-technologies, tactics and capabilities.

Additionally, they can go after the satellites, and through very effective decoying and emission management they have made the long range Stand Off strike campaign an inefficient, cost prohibitive and ultimately a failed strategy. Think going after road mobile TEL’s, while having to pick up which of the 5 is real and which a decoy, or a real TEL armed with a decoy weapon. Now imagine having to do this in an environment where your communications are degraded, EMS is contested, GPS is degraded etc. You aren’t going to be able to lob JASSM/SCALP’s etc from 500 km’s for such missions. I used TEL’s as an example but one could replace this with just about anything that needs to be taken out. Things such as radars, launchers, C2 all the way down to tanks, armored vehicles, Comms hubs etc etc.

This increases burden on dynamic targeting and has kept the penetrating mission very relevant and has forced the US for example to ‘stealthify’ the bulk of its force whereas earlier they could have done with having a silver bullet force of highly penetrating aircraft with the vast majority of its force being able to strike from distance or come in once the silver-bullet force has defeated some of the more challenging air-defense threats. As a couple of USAF’s chief of staff’s have described it, stealth is now (for them) the “the Price of Admission”.
There are other ways to achieve survivability and all this is threat dependent. The basic premise is to present a very hard to detect profile, know where the threats reside, ID and categorize the threats, sift between real and ‘pretend’ threats and defeat these threats through more efficient EMS management.

Basic OML profile won’t get you there by itself. You need to know where the threats are (dynamic EW), have extremely capable intel on them (hence the global clandestine SIGNIT programs that nearly all the major powers run – I have provided background on Paladium and other USAF/NSA/CIA ops in the past), and be able to plan targeting in such a way that you stack the odds in your favor.

Hence you will see newer crop of Stealth aircraft (B-2, F-22, and F-35) have OML profiles, very capable ESM and EW suites and either have, or have room to grow their EA abilities as well whereas the F-117 relied solely on its Low RCS profile and practically nothing else. Electronic Warfare can be PASSIVE or ACTIVE, with passive EW being STEALTH, while active portion being Electronic Attack. The current state of the US systems reflect their best mix of Active and Passive means of defeating the threat in their context. For other users of these systems such as The Chinese or Russians that are also investing heavily in stealth on aircraft – the amount of stealth they design will depend upon their threats, and their abilities to do the trades and produce balanced designs.

Going back to the point about the choice of adopting stealth designs on combat aircraft – It’s a trade as I have explained, but a trade for one may not be a trade for another. With access to cheaper, lighter and more robust materials, or very high end propulsion technologies, one design team need not make the same design trades as another that does not have access to these things. At the end of the day the amount of ‘survivability’ you procure or bake into a system either through active or passive means is highly dependent on the threat, and sensitive to your other capabilities and your cost/risk appetite.

To end, I'd say that how operational requirements emerge is highly dependent on the threat, technology capability and the operational construct that the hardware being designed is going to be used in. This means different air-forces will approach this differently and what applies for one need not apply for the other. What the bulk adoption of LO shaping and accompanying mission system requirements has shown (US, Russia, China, India, South Korea, Japan, Turkey etc etc. ) is that EMS suppression is still very well done by first making yourself hard to find, fix and ultimately target. The loop is the same for an offensive or defensive mission so designers within the scope of their mandate will continue to find ways to make their aircraft hard to find, or ultimately target.

https://i.imgsafe.org/1f80668016.png

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Re: Stealth in military aviation, pros and cons

Postby Manish_Sharma » 09 Sep 2016 05:47

Welcome back Brar!

I have a question you said :
a) The B-2 was the first aircraft designed around broadband stealth requirements no doubt because of its strategic mission requirements.
b) F-22 and F-35 were designed to break kill chains while also meeting other traditional fighter-


By these two bolded parts, you mean that B2 is invisible to certain radars..
&
F-22 + jsf are designed to be invisible to different type of radars?

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 09 Sep 2016 05:55

"Invisible" is a poor description when the goal is to be survivable. The B-2 had broadband stealth requirements which means that its designers were given the freedom to design to reduce its signature over a much larger band given its mission and available technology. I have in the past posted on the physics of why a flying wing would have significant RCS reduction over much larger swaths of the EMS.

The F-22 and JSF were designed around competing requirements i.e. Low-Observability, Supersonic speeds, Supercruise (F22), fighter-like maneuverability (both are 9G fighters) etc so naturally survivability would have to be traded for other considerations. Like I said, the objective here is to break kill chains and use other onboard, and off board means to denying surveillance radars the sort of SA they need to give meaningful tactical advantage to their users.

Traditionally, fighter aircraft have been equipped with EW and EA (active) suits to help them break kill chains. While this has worked at times, and hasn't in other times it was felt that simply increasing the power of self-defense jamming suites wouldnt get you the type of survivability that would be 'acceptable' to a penetrating fleet (may be OK for a stand-off fleet). Looking at the long list of self-defense EA/EW suits fielded by western air-forces (US, France, Sweden, israeil, UK etc) they are looking to provide end-game protection in roughly in the H to J bands. It had been long felt that beefing up EA/EW within the design constraints would simply not be enough for a force expected to be able to play around, around these highly capable IADS. What the stealth provides them is protection over a similar swath of the EMS and by all accounts, at levels unobtainable through EA (given similar competing design constraints).

Simply put, Stealth is PASSIVE Electronic Attack - it reduces RCS in all aspects within a desired range without consuming mission systems (mostly). You layer up EA on top of this for further protection as long as you have EW assisted capability that lets you intelligently use this capability without negating other advantages.

So within a particular band in some instances the new aircraft may be much harder to detect given certain mission profiles compared to the B-2, the B-2 is however going to have lower RCS over a much wider frequency range just given its basic shape and design. This is purely looking at this using an OML+RAM/RAS aspects, when being 'survivable' has other components particularly in the ESM, EW/EA side of things which could level the playing field when combined with the overall integrated capability that these aircraft could leverage. Quite a lot has been acheived with the F-35 in this regard, and it wouldn't be surprising if the B-21 piggy backs on a lot of this.

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Re: Stealth in military aviation, pros and cons

Postby shiv » 18 Sep 2016 06:13

From Aviation week:
http://aviationweek.com/defense/closerl ... es-1473771
Image
Caption: The F-117, the first operational stealth combat aircraft, was designed with a computer program which could only predict the reflection of radar waves off of flat surfaces, necessitating a strictly faceted surface. A flat bottom diamond was determined as the ideal shape for a radar-evading aircraft. The shape was dubbed the “Hopeless Diamond” in reference to its poor inherent aerodynamics. Engineers cut out the minimum necessary to allow the shape to fly.

ImageCaption: This front view of the F-117 shows the screens covering the engine intakes. The screen blocks most radar waves and trap the rest inside. Note also the hexagonal auxiliary intakes with edges aligned with the main intakes and side of the fuselage and the sawtooth pattern surrounding the canopy.

ImageCaption:Tacit Blue was a technology demonstrator built in the early 1980s that influenced later stealth aircraft such as the B-2. It proved stealthy aircraft could have curved surfaces and operate radars without being detected. Note the very narrow edges, to minimize edge diffraction, and the blended facets that compose the airframe.

ImageCaption: From above, the strict planform alignment of the Lockheed Martin F-22 becomes apparent. The angle of the forward fuselage is the same as the leading edges of the wings and horizontal tails as well as the inner trailing edge of the horizontal tail. The angle of the side fuselage is the same as the lateral edges of the wing and horizontal tails. The angle of the outer trailing edges of the horizontal tails match the trailing edges of the wings.

ImageCaption: This frontal view of the F-22 highlights an iridescent canopy—evidence of metallization—as well as the planform alignment of the fuselage sides and vertical tails

Image Caption: A Lockheed Martin F-22 from the side. Note the sheen of the skin, indicating the presence of RAM and the band of lighter gray around the wings, tails and engine inlets, indicating the presence of edge treatments.

ImageCaption: The Irbis-E radar on Sukhoi’s Su-35 has an impressive range against conventional aircraft because of its large aperture and high peak power. But its X-band operating frequency restricts the range at which it can detect targets with a low radar cross section in X-band.

ImageCaption: The 55Zh6UME is one of the most advanced VHF-band radars in operation. Its AESA antenna and other advancements likely allow it to detect stealth fighters at far greater ranges than higher-band radars. It also has far better accuracy than earlier VHF-band radars but is still probably not accurate enough to target missiles.

ImageCaption: Sukhoi’s new T-50 PAK FA fighter carries an N036 radar suite with five AESA antennas, including two of these N036L-1-01 L-band antennas in the leading edges of its wings. Their operation in L-band could provide them with early warning of approaching stealth aircraft. The N036L-1-01 might also be integrated on the Su-35.

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 20 Feb 2017 06:27

Northrop's stealth jets (minus B-2 and UAV's) from Tony Chong's last book -

Image

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Re: Stealth in military aviation, pros and cons

Postby ShauryaT » 20 Feb 2017 07:07

Let me x-post here also. It is more to do with the role of stealth for India and how we can best leverages it. Cost, time and risk being the biggest impediments to the full fledged stealth fighter fleet.

What if we focus AMCA to be an unmanned stealthy sensor detector, so with an AESA, IR, EOTS, RF, RWR, ESM, ECM providing the observation and orientation functions. But let the decision and action functions be controlled by a larger aircraft, staying a few 100 KM's from the sensor detector. The larger aircraft would have the sensor fusion functions on larger processors, with the ability to carry all type of LR A2A, A2G missiles and subsequently uses the stealthy sensor detector craft to cue in these long range weapons.

Advantages:

1. Such an unmanned stealthy AMCA would be cheaper to build and deploy. It would not need supercruise or even supersonic. No sensor fusion needed on the craft. No subsequent safety measures. Being relatively cheaper and unmanned the risk of it being shot down is affordable. You can deploy in mass.
2. All this data being collected from multiple sensor drones is collected and fused on a much large system, say on an IL-76 or C-130 type, let us call this the mother ship
3. Based on mission profile, the C-130 may stock up with A2G or ER BVR A2A weapons or both.
4. The mother ship is also accompanied by 4G fighters as backup
4. The costs for this system in offensive mode would be the relatively low cost sensor detectors and the relatively low cost A2G weapons. The ability to carry them in mass on larger mother ships or non stealthy fighters would be an advantage that will overwhelm most SAM systems.
5. In A2A mode, the cueing offered by the unmanned sensor detector will raise the pK of BVR missiles.

What's the purpose of this. The costs to build a bull blown 5G fighter with all its gizmos for India in meaningful timeframes is not an easy exercise. We are at least 20 years away from it. Instead, should we not focus on building an aircraft that can penetrate enemy air space but yet does not have the all the qualities of a fighter to escape if detected and that is affordable. Also focus on LR, low cost mass deployable weapons.

One huge issue with all 5G fighters is the payload they can carry, while remaining stealthy. The costs simply go up astronomically, when trying to build all this capabilities of a fighter, A2G, sensor detector and fusion on one single manned platform.

Thoughts?

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Re: Stealth in military aviation, pros and cons

Postby JayS » 20 Feb 2017 10:13

ArmenT wrote:
* Note that while the F-117 was originally designated to be a fighter (which is why the name starts with F), it doesn't maneuver all that well, which is why it was actually used as a bomber and only at night time too so that it could not be easily seen, because they did not want it ever being in a turning dogfight scenario, which was its major weakness.



Interesting. In one documentary that NRao posted recently in International Aerospace thread on F117, they said, F designation was given only for prestige as they wanted best pilots to fly it but Fighter pilots would not be very excited to fly a B designated aircraft.

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Re: Stealth in military aviation, pros and cons

Postby JayS » 20 Feb 2017 10:26

Another interesting tidbit from the Video lecture posted by Brar_w in US mil thread:

https://www.youtube.com/watch?v=u-cfy-k_8ew

Skunkworks originally came up with a stealth STOVL concept which was a canard aircraft dubbed as Ghost Hawk STOVL. See above video 41 min onwards. The project was curtailed and the data related to this concept was all shredded. After a few years when LM had to write a proposal, they had only F-22's data at hand and they used that. Thats the reason F-3 looks so much like F-22..! This is coming from Dr Bevilaqua who was a key figure in F-35 project.

He also shows one slide of the jets he proposed as Common Strike Fighter for the first time for Navy + Marine. The configuration shown there (around 44 min in above video) is very much like what J-20 looks now..!!

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Re: Stealth in military aviation, pros and cons

Postby kit » 20 Feb 2017 10:57

brar_w wrote:One must remember stealth is a means to an end. The end being the ability to be survivable against an adversary armed to defeat you by denying access to certain areas and capabilities. Both Russia and China have seen what happened in the GW and Kosovo and have since then invested heavily in denying the US and its allies the use of their integrated strike-complexes, standoff weaponry and PGM’s. This they have done by distributing their Command and Control, by investing in long range air-defenses, long range fighters, kinetic and non kinetic anti_PGM effects, and long range weaponry specifically designed to go against the battle managers. They and others have seen what the second offset technologies have enabled, and have invested in counter-technologies, tactics and capabilities.

Additionally, they can go after the satellites, and through very effective decoying and emission management they have made the long range Stand Off strike campaign an inefficient, cost prohibitive and ultimately a failed strategy. Think going after road mobile TEL’s, while having to pick up which of the 5 is real and which a decoy, or a real TEL armed with a decoy weapon. Now imagine having to do this in an environment where your communications are degraded, EMS is contested, GPS is degraded etc. You aren’t going to be able to lob JASSM/SCALP’s etc from 500 km’s for such missions. I used TEL’s as an example but one could replace this with just about anything that needs to be taken out. Things such as radars, launchers, C2 all the way down to tanks, armored vehicles, Comms hubs etc etc.

This increases burden on dynamic targeting and has kept the penetrating mission very relevant and has forced the US for example to ‘stealthify’ the bulk of its force whereas earlier they could have done with having a silver bullet force of highly penetrating aircraft with the vast majority of its force being able to strike from distance or come in once the silver-bullet force has defeated some of the more challenging air-defense threats. As a couple of USAF’s chief of staff’s have described it, stealth is now (for them) the “the Price of Admission”.
There are other ways to achieve survivability and all this is threat dependent. The basic premise is to present a very hard to detect profile, know where the threats reside, ID and categorize the threats, sift between real and ‘pretend’ threats and defeat these threats through more efficient EMS management.

Basic OML profile won’t get you there by itself. You need to know where the threats are (dynamic EW), have extremely capable intel on them (hence the global clandestine SIGNIT programs that nearly all the major powers run – I have provided background on Paladium and other USAF/NSA/CIA ops in the past), and be able to plan targeting in such a way that you stack the odds in your favor.

Hence you will see newer crop of Stealth aircraft (B-2, F-22, and F-35) have OML profiles, very capable ESM and EW suites and either have, or have room to grow their EA abilities as well whereas the F-117 relied solely on its Low RCS profile and practically nothing else. Electronic Warfare can be PASSIVE or ACTIVE, with passive EW being STEALTH, while active portion being Electronic Attack. The current state of the US systems reflect their best mix of Active and Passive means of defeating the threat in their context. For other users of these systems such as The Chinese or Russians that are also investing heavily in stealth on aircraft – the amount of stealth they design will depend upon their threats, and their abilities to do the trades and produce balanced designs.

Going back to the point about the choice of adopting stealth designs on combat aircraft – It’s a trade as I have explained, but a trade for one may not be a trade for another. With access to cheaper, lighter and more robust materials, or very high end propulsion technologies, one design team need not make the same design trades as another that does not have access to these things. At the end of the day the amount of ‘survivability’ you procure or bake into a system either through active or passive means is highly dependent on the threat, and sensitive to your other capabilities and your cost/risk appetite.

To end, I'd say that how operational requirements emerge is highly dependent on the threat, technology capability and the operational construct that the hardware being designed is going to be used in. This means different air-forces will approach this differently and what applies for one need not apply for the other. What the bulk adoption of LO shaping and accompanying mission system requirements has shown (US, Russia, China, India, South Korea, Japan, Turkey etc etc. ) is that EMS suppression is still very well done by first making yourself hard to find, fix and ultimately target. The loop is the same for an offensive or defensive mission so designers within the scope of their mandate will continue to find ways to make their aircraft hard to find, or ultimately target.

https://i.imgsafe.org/1f80668016.png


What brar has said here is definitely significant for the Indian forces as they face off China in north east

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Re: Stealth in military aviation, pros and cons

Postby Arun.prabhu » 20 Feb 2017 12:49

Low observability is a big deal today because America have a monopoly on it - operational aircraft. But it isn't a magic wand that makes an aircraft unbeatable. In modern combat, be it on air, land and sea, if you can see it, you can kill it. This gives low observable planes an inherent advantage over their normal counterparts today and acts as a force multiplier. Does this mean that the answer is to go low observable across the military air craft spectrum to negate the advantage of low observable aircraft? Personally, I don't believe the issue is so cut and dried.

On aircrafts, passive detection works against Low Observable aircraft today. IRST can track them at a range of 90 km from the rear and 50 km from the front. Ideally, we would want longer range to take advantage of missiles and because a single Low Observable aircraft flying in a squadron can light up the sky and ruin your and your squadron mate's day if it can share the data with its friends. So, detection of Low Observable aircraft at longer ranges is a must and nothing works as well as radar on that front. The key, I think is that radar absorbent materials are not invisible throughout the EM spectrum or even exhibit uniform absorption characteristics across different radio and microwave bands. A radar that can emit pulses across multiple bands should work. Technically a tall ask, but I think much cheaper than to research, build and operate than a low observable aircraft. And unlike an airframe, easier to upgrade/replace.

In combat, how would I defeat an low observable incursion into my airspace?
1. Tethered balloons close to the front with IRST. Longer LOS, so farther detection of aircraft flying nape of earth and maybe an AAM with a IR seeker or two every few balloons to really light up a pilot's day. Power can be supplied through the tether to the sensors, and weight wouldn't be as big an obstacle as it would be on a heavier than air craft. We needn't worry about survivability of the platform on launch of AAM because a balloon is cheap and we can have different balloons for sensors and missiles. Lost balloons and sensors would be far easier and cheaper to replace than radar sites or an AWACS. There is also the advantage that since the sensors are passive, taking them out will be harder and may not make much sense since a downed balloon can be replaced in short order.

2. A cheap fleet of armed autonomous UAVs requiring manual intervention for launch and landing alone each with again one or two IR seeker equipped AAMs. On detection, launch the UAVs. The enemy has to engage them lest they be engaged and each missele they expend is one less they can use on manned fighters. The UAVs needn't be very high tech capable of high-G manoeuvres. Fly straight with decent sensors and as cheap as possible because they are expendable. Even propeller driven would be fine because they are there to soak up enemy fire. Networking capability would be great if we could make it cheap enough. Something like what APJ Kalam had in mind when he talked about missiles that can loiter and return to base.

No 2 has the advantage that LO aircraft are very expensive and so can't be used en masse. Also, ordinance has to be carried in internal bays to maintain LO characteristics, which restricts throw weight. This is something that I think APJ Kalam was on to when he asked for missiles that can loiter in the air and return to base.

3. Expensive manned aircraft with all the latest in tech that we can equip our pilots with networking capability to use data feed from a variety of sensors - ground and air based - to hunt the enemy after they have expended a considerable quantity on their onboard munitions on our cheap-ass drones.

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Re: Stealth in military aviation, pros and cons

Postby bmallick » 20 Feb 2017 14:13

A question.

Let us say a bunch of Low Observable Fighters are coming in to attack a base. One of them, moves to some distance away from the others, maybe ahead or some other direction. It uses its radar to look out for the defenders and then shares the information with the others. In both the cases it is transmitting radio waves. So why cannot someone pick up those transmissions.

Also, to constantly track the defenders the Radar cannot work in a burst mode. I understand LPI mode, but maybe I am a layman, but still cannot understand, why such near continous radio transmission cannot be picked up. Moreover, sharing the same data continuously with others, too should be possible to pick up. Yes frequency hopping might be there, but still the airborne system can only work in a narrow band of waves, not jump around the entire spectrum.

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 20 Feb 2017 15:59

Arun.prabhu wrote:On aircrafts, passive detection works against Low Observable aircraft today. IRST can track them at a range of 90 km from the rear and 50 km from the front.


Low observable aircraft have or attempt to have IR signature reduction measures as well. This is done in the design phase, through requirements and through things like having IR reducing features incorporated (sometime at expense of performance) in the actual hardware to reduce the signature in the Infrared spectrum.

There are even IR topcoat coatings that have been used for decades on these aircraft. What you have just quoted is detection range performance of IR detection and targeting systems. How well they perform, how reliable they are, and how they fit into a kill chain against a target that has been designed around an IR signature requirement is unknown to the general public. These can be seen in design trades, the design space allowed to things like different nozzle configurations, heat sinks, cooling channels etc etc. Different stealth aircraft have incorporated this to a different degree and its something that is traded much like any other design feature.

Designers have paid attention to both active and passive means of detection and evaluators have built these detection mechanisms into their evaluation process during hardware testing so that IR signature is measured to requirement. This data is then used by the tacticians to develop tactics, and know limits of their hardware so as to optimize their performance against all means of detections.

This applies to the RF, and IR spectrum and both active RF i.e. Radar RCS from different angles (that needs to be measured and modeled) and passive detection in the RF domain i.e. EMCON.

Below is an F-22 undergoing IR signature measurement using a specialized sensor designed to measure its IR signature against various IR spectrum sensors. Also a brief article about Top Coat --

Image

Image

http://boeing.mediaroom.com/2000-03-23- ... -22-Raptor

Get close enough and you can be detected by various means, including RF, IR, visual etc but the entire point of spectrum suppression is to make yourself extremely hard to detect, track and target so that you can deploy your weapons inside your opponents OODA loop.

The key, I think is that radar absorbent materials are not invisible throughout the EM spectrum or even exhibit uniform absorption characteristics across different radio and microwave bands. A radar that can emit pulses across multiple bands should work. Technically a tall ask, but I think much cheaper than to research, build and operate than a low observable aircraft. And unlike an airframe, easier to upgrade/replace.


RAM is also in continuous process of development. Aviation Week described a Lockheed patent that takes a FiberMat approach of using a very wideband application that is covering right down to the L band. RAM has been in constant development, at least int he US for well over 3 decades.

BTW Which radar emits pulses across multiple Radar bands? How you put something like that on a fighter in terms of physics.

bmallick wrote:A question.

Let us say a bunch of Low Observable Fighters are coming in to attack a base. One of them, moves to some distance away from the others, maybe ahead or some other direction. It uses its radar to look out for the defenders and then shares the information with the others. In both the cases it is transmitting radio waves. So why cannot someone pick up those transmissions.

Also, to constantly track the defenders the Radar cannot work in a burst mode. I understand LPI mode, but maybe I am a layman, but still cannot understand, why such near continous radio transmission cannot be picked up. Moreover, sharing the same data continuously with others, too should be possible to pick up. Yes frequency hopping might be there, but still the airborne system can only work in a narrow band of waves, not jump around the entire spectrum.


Of course can be picked up. What you are working on here is with probabilities that is, you have a low to very low RF signature, practice EMCON i.e. use your active sensors sparingly, and have incorporated disciplined RF management across your other emitters such as data links and communicaitons . LPI techniques downgrade the radar performance and also make it harder (not impossible) to detect leave aside triangulate, track and locate. It is still Low probability of Intercept and not No probability of intercept.

LPI/LPD data links such as MADL and IFDL (F-35 and F-22) are directional, fast and shorter range (because of both high speed requirements and LPI / LPD designs) and using these in combination with distributed sensors and LPI/LPD radars affords you an opportunity to develop Situatioanl Awareness on a target without any one aircraft having to emit a disproportionately high amount of RF energy. These sensors are not operating in a vacuum either, they are working in concert with a multi ship equipped with highly sophisticated ESM suites and some also with IR spectrum sensors.

EMCON and spectrum management is extremely important on stealth fighters..there is a reason that the F-22 and F-35 designers went out of the NATO Link-16 communication and built an additional layer of LPI/LPD directional, communication and automatic SA sharing processes. F-22 came with bi-directinoal IFDL + Standard NATO Link-16 (receive). Upgrades will give it a Link-16 transmit and an additional MADL terminal. F-35 comes with MADL plus bi-directional Link-16 from the get go.

Signature management has two broad goals. One is to reduce your RCS and practice EMCON so you can hide behind the noise, and the other is to force your adversary to increase his level of radiation to bring your own passive sensors into play. On the F-22 and F-35 (two operational stealth fighters) it is often said that the AN/ALR- 94 and AN/ASQ-239 are the most sophisticated sensors onboard. While this may be true technically, given the complexity of integrating up to 30 antennas, both active and passive in the wings and fuselage it is actually the fusion engine that is the most sophisticated thing especially on the F-35 where it is feeding raw data into the processors and utilizing bits and pieces of each sensor to PID a target.

So you aren't just relying on an LPI radar..your detection and tracking is happening using your own Electronic Warfare system, bits of your radar and even your IR suite. And not just yours, but that of each aircraft in a four ship or even larger formations. MADL has the ability to seamlessly connect with up to 25 terminals.

Image

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Re: Stealth in military aviation, pros and cons

Postby Rishi Verma » 20 Feb 2017 16:49

Again another topic for arm chairs to fill pages with. All that's needed was an excel sheet to weigh the pros and cons.

Here's my two lac phooti kodi.

1) stealth is to defeat the enemy radar
2) even bigger game is enemy deception by any means possible
3) positive stealth is to hide your plane
4) negative stealth is to deceive the enemy radar that a swarm of fighter's is just a balloon (radar echo emulation with phase/magnitude shift)
5) ultimate stealth is to have no planes in the air... Hit them with unknown "things"

No one does stealth design like climbing a mountain "because it's there", it's done to kill enemies with the unknown... that's stealth and not a $2B flying wing .. it's just american hype....or American psychops...

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Re: Stealth in military aviation, pros and cons

Postby TSJones » 20 Feb 2017 17:13

Rishi Verma wrote:Again another topic for arm chairs to fill pages with. All that's needed was an excel sheet to weigh the pros and cons.

Here's my two lac phooti kodi.

1) stealth is to defeat the enemy radar
2) even bigger game is enemy deception by any means possible
3) positive stealth is to hide your plane
4) negative stealth is to deceive the enemy radar that a swarm of fighter's is just a balloon (radar echo emulation with phase/magnitude shift)
5) ultimate stealth is to have no planes in the air... Hit them with unknown "things"

No one does stealth design like climbing a mountain "because it's there", it's done to kill enemies with the unknown... that's stealth and not a $2B flying wing .. it's just american hype....or American psychops...


not having stealth makes hitting an enemy harder to perform. stealth is not undertaken lightly. its a major investment in experience and resources, both blood and treasure. if you don't progress technologically, then you becomes somebody else's meat.

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Re: Stealth in military aviation, pros and cons

Postby bmallick » 20 Feb 2017 17:25

Few more questions.

A. How feasible it is in 3-D space to know where the other fellow is to enable directional communication?

B. Does stealth imply that, your aircrafts have to mostly rely on others to do the searching for you, rather than itself. Otherwise,if it is forced to use its Radar continuously to scan and track, it would be caught. In that case, does it even make sense to have a Radar on board a stealth aircraft?

C. Does it mean that a lot of things, like RAM Coat, off board sensors, data link communication, heavy bandwidth & fast data transmission,have to work seamlessly to enable stealth aircrafts to perform at the peak. Is that something that makes the entire building brittle and would it survive the fast moving, low maintenance, fly with issues, things not working, environment of a peer conflict. Is it worth it?

Added Later: Not evolving technologically of course makes one food for other. But the path of Stealth Aircraft is not necessarily the only way to evolve. There are many paths to evolution and only time decides which survives. Only, when we choose to questions one set of "Gospels" can we come with path.

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Re: Stealth in military aviation, pros and cons

Postby Arun.prabhu » 20 Feb 2017 17:59

brar_w wrote:
Arun.prabhu wrote:On aircrafts, passive detection works against Low Observable aircraft today. IRST can track them at a range of 90 km from the rear and 50 km from the front.


Low observable aircraft have or attempt to have IR signature reduction measures as well. This is done in the design phase, through requirements and through things like having IR reducing features incorporated (sometime at expense of performance) in the actual hardware to reduce the signature in the Infrared spectrum.

There are even IR topcoat coatings that have been used for decades on these aircraft. What you have just quoted is detection range performance of IR detection and targeting systems. How well they perform, how reliable they are, and how they fit into a kill chain against a target that has been designed around an IR signature requirement is unknown to the general public. These can be seen in design trades, the design space allowed to things like different nozzle configurations, heat sinks, cooling channels etc etc. Different stealth aircraft have incorporated this to a different degree and its something that is traded much like any other design feature.

Designers have paid attention to both active and passive means of detection and evaluators have built these detection mechanisms into their evaluation process during hardware testing so that IR signature is measured to requirement. This data is then used by the tacticians to develop tactics, and know limits of their hardware so as to optimize their performance against all means of detections.

This applies to the RF, and IR spectrum and both active RF i.e. Radar RCS from different angles (that needs to be measured and modeled) and passive detection in the RF domain i.e. EMCON.

Below is an F-22 undergoing IR signature measurement using a specialized sensor designed to measure its IR signature against various IR spectrum sensors. Also a brief article about Top Coat --

Image

Image

http://boeing.mediaroom.com/2000-03-23- ... -22-Raptor

Get close enough and you can be detected by various means, including RF, IR, visual etc but the entire point of spectrum suppression is to make yourself extremely hard to detect, track and target so that you can deploy your weapons inside your opponents OODA loop.


Any aircraft doing hundreds of knots carrying is going to emit jet exhaust, which is going to have a thermal signature. There are ways to suppress the signature, as you note, but how it is nowhere near perfect. An aircraft that absorbs radar energy and doesn't emit thermal radiation is going to have to emit the absorbed radar energy and generated heat from engine, onboard systems and friction in some way. [j/k]That pretty much rules out all emission bands except ionising radiation, visual and UV. The question then becomes, would this theoretical aircraft light up the sky like a giant 100kW bulb or would it kill the pilot with radiation poisoning? [/j/k]

The point is, energy is conserved and LO aircraft aren't optimized for IR spectrum as they are for some bands of radar and microwave. what is absorbed must be reflected in some other spectrum. And we can detect that.

As for OODA loop, it depends on the nature of the air war you plan to fight. Sure, if you go for expensive to buy, maintain and operate, hard to replace platforms manned by expensive to pay and maintain and hard to train personnel then you can't bear to lose anything, the American approach makes sense, but what if you go dead cheap and can afford to lose ten-twenty-or even fifty cheap platforms to your opponents one fighter? (incidentally, I believe this is the main reason why the USAF hasn't been the greatest supporter of UAVs in the world.) This is the strategy that I outlined in the bottom of my post. All the OODA in the world isn't going to do you an iota of good when you can observe and orient, but can't act to engage because you have used all your high-tech, very expensive, limited quantity munitions on drones that are perhaps twice the cost of your missile. Good luck with OODA in that case. Playing war the way the Americans play it isn't the only way to do it. And even America can't go stealth all the way. Less than 200 F-22s and how much are they spending on F-35s over its lifetime? I've heard a trillion dollars! ROTFLOL All hail the fighter mafia!

brar_w wrote:
The key, I think is that radar absorbent materials are not invisible throughout the EM spectrum or even exhibit uniform absorption characteristics across different radio and microwave bands. A radar that can emit pulses across multiple bands should work. Technically a tall ask, but I think much cheaper than to research, build and operate than a low observable aircraft. And unlike an airframe, easier to upgrade/replace.


RAM is also in continuous process of development. Aviation Week described a Lockheed patent that takes a FiberMat approach of using a very wideband application that is covering right down to the L band. RAM has been in constant development, at least int he US for well over 3 decades.

BTW Which radar emits pulses across multiple Radar bands? How you put something like that on a fighter in terms of physics.


The soviets built a multi-band radar in the 1980s for the Mig-31.

https://en.wikipedia.org/wiki/Zaslon

So, it is not technically impossible. Managing the power and miniaturising the emitters, and cooling the whole assembly would be' interesting,' but the idea would be to build the plane around the radar - kind of like how the Warthog was built around the gun.

As for RAM that works across multiple radar bands, have they been productionized? Or are they merely curiosities in the lab today? I'd love to see how an aircraft that suppresses thermal signature and absorbs radar across all bands manages heat. And I'd love to see other nations spend their national wealth pursuing that dream. Me, give me cheap, reasonably good weapons and platforms that can be used in mass - the same mass also gives me tactical flexibility because I wouldn't be constrained by the number of aircraft I can deploy - and I'm good. Drones all the way.

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 20 Feb 2017 18:55

Arun.prabhu wrote:Any aircraft doing hundreds of knots carrying is going to emit jet exhaust, which is going to have a thermal signature. There are ways to suppress the signature, as you note, but how it is nowhere near perfect.


Could you point me to where I said it was perfect?

An aircraft that absorbs radar energy and doesn't emit thermal radiation is going to have to emit the absorbed radar energy and generated heat from engine, onboard systems and friction in some way.


Hence thermal management is important not to make a stealth aircraft undetectable in the IR spectrum but to delay detection which just as RF suppression has an end goal of seeing and targeting first using your own Active and Passive means.

The point is, energy is conserved and LO aircraft aren't optimized for IR spectrum as they are for some bands of radar and microwave. what is absorbed must be reflected in some other spectrum. And we can detect that


As I have shown, there are a number of ways a modern stealth aircraft designer addresses IR signature suppression. How that compares to the RF suppression attempts is a matter that is likely to be classified given that the only folks with access to actual signatures aren't going to be talking about it. Needless to say, my point was that the ranges you were citing for some of the systems are hardware performance numbers. We have no proof in the open source whether those ranges are using targets that address the IR spectrum and if so to what extent.

https://basicsaboutaerodynamicsandavion ... -benefits/

Less than 200 F-22s


Care to share the number of operational PAFA/T-50's in service? How about in service (expected) by 2020, and 2030? The biggest reason as to why there are sub-200 F-22's is the lack of need. It was a cold war legacy air superiority fighter that had to justify its place in the US budget post cold war and at a time when the US was spending a very high amount of money elsewhere. If a legitimate threat had remained more would have been acquired and much like the Eagle/Strike Eagle you would have seen F-22B and C variants as well. In their wisdom the Secretary of Defense at the time, along with the Congress decided to truncate the program, invest in a more multi-role platform and keep investing in future technologies that would enable future generation aircraft. As a compromise and as a hedge they preserved all tooling on the F-22 in case a threat rapidly developed and the program needed to be re-started.


How much are they spending on F-35s over its lifetime? I've heard a trillion dollars! ROTFLOL All hail the fighter mafia!


Again, care to share with me a 55-60 year O&S cost in USD (In a US cost environment) for 2400+ Su-30MKI's and/or a combination of Su-30's and Rafales. If air frames require SLEP to keep them at 8000 hrs add the SLEP cost as well. Thanks in advance. I would like for you to add the cost of an MKI or rafale variant that is carrier bound, and also one that can support STOVL operations both on sea and land. To be exact, that is 19200000 hours of fast jet operation over 5+ decades including the cost of fuel, and O&S cost inflated to then year dollars. And not all of those are CTOL, land based fighters. A fourth of them are CV or STOVL.

The soviets built a multi-band radar in the 1980s for the Mig-31.


It uses an L band transponder.

This approach is also used elsewhere btw on all modern fighters. The F-35's IFF Interogators are located on the leading edge of the wings -

Image

On other legacy fighters they are located right above the radome -

Image

So, it is not technically impossible. Managing the power and miniaturising the emitters, and cooling the whole assembly would be' interesting,' but the idea would be to build the plane around the radar - kind of like how the Warthog was built around the gun.


You will still run into physics when you look beyond IFF functions. You can't miniaturize a low frequency antenna to a point where it begins to compete with a higher frequency one chosen on fighters. The antenna has to grow commensurate to the wavelength you select or else your resolution will be terrible.


So, it is not technically impossible. Managing the power and miniaturising the emitters, and cooling the whole assembly would be' interesting,' but the idea would be to build the plane around the radar - kind of like how the Warthog was built around the gun.


Building an aircraft around a radar is what you do with AEW and AWACS. Much the same as Lockheed has built the E-2D around its UHF radar, or Northrop and IAI the E-7 and Phalcon around their L band AESA's. Lower frequency radars require size for proper resolution. Also, As a matter of physics, given a set aperture size beam-width is proportional to your wavelength/aperture length. In other words a higher frequency radar will deliver a narrower beamwidth given a fixed aperture size hence fighter based FCR's prefer to operate in this region, and why AWACS can afford to field lower frequency sensors and still detect and track a large number of targets that are often flying close to each other.

As for RAM that works across multiple radar bands, have they been productionized?


FiberMat is in production and currently incorporated on all operationally configured F-35s,

I'd love to see how an aircraft that suppresses thermal signature and absorbs radar across all bands manages heat.


The key word is "manages" and not totally negates any IR signature. As explained, the concept involves reducing IR footprint to acceptable levels in order to gain tactical advantage i.e. the same way you suppress RF signature. Of course we know that IR is a poorer form of targeting than RF hence radar remains the primary sensor for all fighter applications. You don't need to hide as much from the IR spectrum as you do from an IR one. No one is going to be lobbing 100km RF interceptors at you based on a faint heat signature.

Me, give me cheap, reasonably good weapons and platforms that can be used in mass - the same mass also gives me tactical flexibility because I wouldn't be constrained by the number of aircraft I can deploy - and I'm good. Drones all the way.


You must hate the AMCA as it currently stands, because many of the features are being incorporated on it as well.
Last edited by brar_w on 21 Feb 2017 07:09, edited 2 times in total.

Arun.prabhu
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Re: Stealth in military aviation, pros and cons

Postby Arun.prabhu » 20 Feb 2017 20:18

brar_w wrote:
Arun.prabhu wrote:Any aircraft doing hundreds of knots carrying is going to emit jet exhaust, which is going to have a thermal signature. There are ways to suppress the signature, as you note, but how it is nowhere near perfect.


Could you point me to where I said it was perfect?


Typo on my part. I was agreeing that it is nowhere near perfect.

brar_w wrote:
An aircraft that absorbs radar energy and doesn't emit thermal radiation is going to have to emit the absorbed radar energy and generated heat from engine, onboard systems and friction in some way.


Hence thermal management is important not to make a stealth aircraft undetectable in the IR spectrum but to delay detection which just as RF suppression has an end goal of seeing and targeting first using your own Active and Passive means.


Thermal management is a deadend street. There is only so much thermal management one can do and sensors are improving all the time.

brar_w wrote:
The point is, energy is conserved and LO aircraft aren't optimized for IR spectrum as they are for some bands of radar and microwave. what is absorbed must be reflected in some other spectrum. And we can detect that


As I have shown, there are a number of ways a modern stealth aircraft designer addresses IR signature suppression. How that compares to the RF suppression attempts is a matter that is likely to be classified given that the only folks with access to actual signatures aren't going to be talking about it. Needless to say, my point was that the ranges you were citing for some of the systems are hardware performance numbers. We have no proof in the open source whether those ranges are using targets that address the IR spectrum and if so to what extent.

https://basicsaboutaerodynamicsandavion ... -benefits/

Less than 200 F-22s


Care to share the number of operational PAFA/T-50's in service? How about in service (expected) by 2020, and 2030.

I think I have already made my thoughts on low observability clear. I wouldn't miss a night's sleep if PAFFA didn't enter service. :)

You're right those are hardware performance numbers. We don't know what the range is against F-22 and F-35. But if you go back to my air defence strategy, I did not say that all the IRST sensors have to pointed towards our neighbours. Have some look inside India and as our thermally managed stealth aircraft shows its rear as it races into our country, fire an SAM up its ass.

brar_w wrote:
How much are they spending on F-35s over its lifetime? I've heard a trillion dollars! ROTFLOL All hail the fighter mafia!


Again, care to share with me a 55-60 year O&S cost in USD (In a US cost environment) for 2400+ Su-30MKI's and/or a combination of Su-30's and Rafales. If air frames require SLEP to keep them at 8000 hrs add the SLEP cost as well. Thanks in advance. I would like for you to add the cost of an MKI or rafale variant that is carrier bound, and also one that can support STOVL operations both on sea and land. To be exact, that is 19200000 hours of fast jet operation over 5+ decades including the cost of fuel, and O&S cost inflated to then year dollars.



I don't care to do the calculations. We don't know if 2400 F-35s will actually be bought in the end. How many F-22s were planned and how many bought before the assembly line was shut down and the machines that make the machines that make the F-22 were repurposed or sold? We don't know if F-35 will remain relevant for 55-60 years against parity or near-parity opponents, which America is starting to see now.

Assuming America buys 2400 F-35s, which I personally think won't happen, we get roughly 600 million dollars per plane over its lifetime for a total program cost of about 1.5 trillion dollars. This is assuming that the Air Force numbers are correct. I don't care if America can afford it. I care that India can't afford to spend that much money if that is how much a LO fighter program will cost. We balked at the high cost of the Rafale order when it was ten+ billions (I don't have accurate numbers. sorry) when cost per aircraft over lifetime was less than that of the F-35. We can't afford PAKFA if it costs that much and if AMCA costs similar monies, we can't afford that either.


brar_w wrote:
The soviets built a multi-band radar in the 1980s for the Mig-31.


It uses an L band transponder.


Now you're quibbling. multiple bands have been demonstrated on a fighter aircraft. Whatever we build to counter low observability should use bands that are useful for the purpose. I don't say that the radar should be limited to L and X-band as the Zaslon was.

brar_w wrote:
So, it is not technically impossible. Managing the power and miniaturising the emitters, and cooling the whole assembly would be' interesting,' but the idea would be to build the plane around the radar - kind of like how the Warthog was built around the gun.


You will still run into physics when you look beyond IFF functions. You can't miniaturize a low frequency antenna to a point where it begins to compete with a higher frequency one chosen on fighters. The antenna has to grow commensurate to the wavelength you select or else your resolution will be terrible.


That is true, but it is an engineering challenge. The engineer in me is tempted to ask, how do we build a low frequency antenna that has a reasonable chance of detecting a LO aircraft at decent range into the body of an aircraft? :)

brar_w wrote:
As for RAM that works across multiple radar bands, have they been productionized?


FiberMat is in production and currently incorporated on all operationally configured F-35s,


Oh, that is interesting. I wonder what the performance is across the different bands? Hmm.

brar_w wrote:
I'd love to see how an aircraft that suppresses thermal signature and absorbs radar across all bands manages heat.


The key word is "manages" and not totally negates any IR signature. As explained, the concept involves reducing IR footprint to acceptable levels in order to gain tactical advantage i.e. the same way you suppress RF signature. Of course we know that IR is a poorer form of targeting than RF hence radar remains the primary sensor for all fighter applications. You don't need to hide as much from the IR spectrum as you do from an IR one. No one is going to be lobbing 100km RF interceptors at you based on a faint heat signature.


Are you claiming IR is a poorer form of targeting based on the Vietnam war experience with Sidewinders, are you referring to some other data?

brar_w wrote:
Me, give me cheap, reasonably good weapons and platforms that can be used in mass - the same mass also gives me tactical flexibility because I wouldn't be constrained by the number of aircraft I can deploy - and I'm good. Drones all the way.


You must hate the AMCA as it currently stands, because many of the features are being incorporated on it as well.
[/quote]

Well, we don't know how much it'll cost and how many we can afford. If it costs a lot and we can afford only a few, it'll join the rest of the LO aircraft in the white elephant list. I have high hopes that cheap UAVs are the way of the future. Forget dogfights, which UAVs can't do, but being a platform for missiles and munitions are right up their alley and that's what modern combat aircraft are - platforms for missiles and munitions optimized for BVR combat with dogfighting as an afterthought.

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Re: Stealth in military aviation, pros and cons

Postby ShauryaT » 20 Feb 2017 20:27

>>Arun.Prabhu
>>And I'd love to see other nations spend their national wealth pursuing that dream. Me, give me cheap, reasonably good weapons and platforms that can be used in mass - the same mass also gives me tactical flexibility because I wouldn't be constrained by the number of aircraft I can deploy - and I'm good. Drones all the way.

+1.

Make it stealthy drones, not stealth multi role fighters with sensors and sensor fusion that has to do it all in one single platform. Stealth does have a role to penetrate contested air spaces, however it does not have to be done the way the US does it. The functions in the OODA loop can be on different platforms?

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Re: Stealth in military aviation, pros and cons

Postby brar_w » 20 Feb 2017 20:33

Arun.prabhu wrote:Typo on my part. I was agreeing that it is nowhere near perfect.


Nothing is including RF. So you base your requirements running stealth and counter stealth trades to see how much this needs to influence your design. My point was that stealth aircraft designers do not neglect the IR spectrum and point worth remembering when quoting brochure ranges for IR hardware, just as we assume that a radar range on a brochure would be impacted by RCS. You can't just throw a blanket range number on IR hardware performance without citing what the baseline target represents. Same with radars..if someone throws a radar range you ought to ask yourself, what RCS, which mode etc. In the US they have standardized on 1 sqm targets (RCS) so naturally whatever range figure they cite for one of their radars will become much less if your target has a smaller RCS.

There are designers, operators and testers that are constantly testing low observable configurations and crafts with counter low observable technologies including testing the IR spectrum across the range. Same within the RF. VHF, UHF, L band and bi-static radars are used to constantly probe at low-observable concepts, aircraft and tactics. It just so happens that the most experienced low frequency surveillance radar OEM in the west is also most experienced at producing low observable aircraft.

And it is not just testing after the fact, but actual requirements mandate IR signature suppression. A quick look at the rear half of the YF-22 and YF-23 would show you different approaches vis-a-vis the exhaust gasses. Plus, the F-119 and F-135 approach has been shared here in the past including a photograph.

Arun.prabhu wrote:I don't care to do the calculations.


My point was not whether you cared to do them or not. It was that you couldn't do it even if you wanted to since the level of detail CAPE uses for its O&S cost isn't available for most other fighters, and even if it were it is not universally applicable. Why would the IAF care on what the USAF spends on manpower, or transporting fuel across the globe? Furthermore, much of these costs are on account of maintaining a fighter fleet i.e. no matter what you buy, if you are committed to operating this sized fighter fleet you will have to bear a lot of this cost irrespective of the fact that you buy an F-35, F-15, F-54, F-72 or whatever. Even assuming that the USAF, USN and USMC buys its currently planned share of 2400 aircraft, the total fighter force will still be quite small compared to what they operated in the Cold War so you match your end strength with your threats and then see if you can afford that or not.

Arun.prabhu wrote: We don't know if 2400 F-35s will actually be bought in the end.


So could you tell me how exactly they will spend to sustain a fleet of 2400 F-35's if they won't buy 2400 F-35s? Let's say they buy 1200 at the end. Will they require the same amount of manpower, fuel, spare parts, and operational base infrastructure to sustain over their lifetime 1200 aircraft as they would 2400?

Arun.prabhu wrote:we get roughly 600 million dollars per plane over its lifetime for a total program cost of about 1.5 trillion dollars.


As a general rule of thumb, fighter aircraft projects tend to have a 1/3 to 2/3 split in terms of development+procurement costs and lifetime O&S costs. I.e. you spend 1/3 of LCC to develop and buy something, and then spend 2/3 in sustaining it. So again, if you aren't going to be buying up hundreds of 8000 hr air frames why on earth will you be spending to sustain them? I have often pointed this out to those that love to cite F-22 production truncation in order to make a point about overall F-35 procurement numbers while at the same time (often in the same post) citing an O&S number that looks extremely large on account of an extremely large purchase. If you don't buy as many, you won't have to maintain as many pilots, as much base infrastructure, buy as much fuel, purchase as many LRUs, upgrade as many aircraft, train as many pilots, preform as many live shots (yes the CAPErs looked at this too) during peacetime etc etc. This shouldn't be a hard concept to understand.

Arun.prabhu wrote:How many F-22s were planned and how many bought before the assembly line was shut down and the machines that make the machines that make the F-22 were repurposed or sold? We don't know if F-35 will remain relevant for 55-60 years against parity or near-parity opponents, which America is starting to see now.


No none of the tooling were re purposed. They are all sitting in an air conditioned storage space out in California as was mandated by the OSD/USAF. When the US expected to buy 600 F-22's, they expected to spend a X amount of dollars in support of those F-22's for 4-6 or so decades of their operational use. A smaller fleet will require less amount. You don't man, or resource for a 200 fighter fleet as if you had 400 phantom aircraft.

A total of more than 30,000 jigs, fixtures and other "tooling" used to build the plane are being logged into a database and tucked into containers, some custom built, for long-term storage at Sierra Army Depot, Herlong, California.

The hardware is valued at $2 billion to $3 billion, according to Lockheed, the Pentagon's No. 1 supplier by sales.

The Sierra depot's high desert climate, low humidity and mild temperatures, are optimal for systems that might be needed to build components to support the fleet, or perhaps one day resume production.

Same with the F-35 numbers you cited. The Trillion dollar cost is from 2000 to 2060 and covers the sustainment as in manpower costs, fuel costs, testing costs, training costs, flight hour costs, basing costs for a fleet of 2400 aircraft and then adjusted for inflation over these 50-60 years. You can't claim that 2400 aircraft would not be purchased and then still cling on to the Trillion dollar price tag which prices out the O&S cost for 2400 aircraft.

Arun.prabhu wrote:Assuming America buys 2400 F-35s, which I personally think won't happen, we get roughly 600 million dollars per plane over its lifetime for a total program cost of about 1.5 trillion dollars. This is assuming that the Air Force numbers are correct. I don't care if America can afford it. I care that India can't afford to spend that much money if that is how much a LO fighter program will cost. We balked at the high cost of the Rafale order when it was ten+ billions (I don't have accurate numbers. sorry) when cost per aircraft over lifetime was less than that of the F-35. We can't afford PAKFA if it costs that much and if AMCA costs similar monies, we can't afford that either.


Like I said, please provide me a comparable number for another fighter. Also, dig into what the O&S cost includes (I've provided extensive details on this forum) and you will realize why that is not relevant to India. And btw, not to nit pick but the USAF does not decide what it's going to cost to sustain its fleet for 5 decades or more. That decision is made by an independent authority.

Arun.prabhu wrote:We don't know if F-35 will remain relevant for 55-60 years against parity or near-parity opponents, which America is starting to see now.


Air Superiority is done as per a roadmap of matching your response to a given threat. F-35 is only one peice of the puzzle just as the F-16 has been over the decades. Having an F-16 did not negate the need for having F-15C's, developing F-15E's, F-22As, and F-117s. Same with the F-35. It is one aspect, and is a mass "quantities" fighter. The PCA is in conception phase and will be in development around the turn of the decade and we'll begin to see it in the early 2030s. No one thing buys you competitiveness over 60 years but collectively they do.

Arun.prabhu wrote:Now you're quibbling. multiple bands have been demonstrated on a fighter aircraft. Whatever we build to counter low observability should use bands that are useful for the purpose. I don't say that the radar should be limited to L and X-band as the Zaslon was.


IFF is different from FCR roles. Even the F-22 and F-35 have wide band coverage built into their EW suites, including for IFF, and including active antennas.

The engineer in me is tempted to ask, how do we build a low frequency antenna that has a reasonable chance of detecting a LO aircraft at decent range into the body of an aircraft?


Detecting isn't going to get you anywhere. The kill chain goes beyond that. Moreover there are matters of physics with respect to antenna size that determine beamwidth in a low frequency radar. Smaller lower frequency radars will not be comparable to higher frequency radars for the purpose of a fighter borne radar. It is for a similar reason that your ground control lower frequency radars are much larger than their higher frequency counterparts. Have you noticed that the smaller and smaller the aperture requirements get the higher the frequency gets for a given military application? Why Missile seeker prefer to operate in the X-Ku band range and why FCR's operate in the X band range and why large surveillance radars (AEW) operate in the UHF-C band range? As an example from missile seekers, an 8 inch fixed antenna diameter gives you a 1 degree beamwidth if you go with a MMW seeker vs a >10 degree beamwidth if you go with X band.

Plus the more you emit the more you broadcast and the more frequencies you emit in the harder it is from an EMCON purpose. ESM and decoy makers would like nothing better than low frequency fighter based radars probing open airspace.

Arun.prabhu wrote:Oh, that is interesting. I wonder what the performance is across the different bands? Hmm.


They have been at it for 35 or so years so it will no doubt have improved by leaps and bounds. The exact performance is obviously classified but there is enough out there in the open source to read up on what they are trying to acheive. I believe ViVS has posted some stuff here on this forum.

Arun.prabhu wrote:Are you claiming IR is a poorer form of targeting based on the Vietnam war experience with Sidewinders, are you referring to some other data?


Long range detecting, tracking and targeting based on Infra Red sensors. It has nothing to do with Vietnam and how the Sidewinders performed.

brar_w
BRF Oldie
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Re: Stealth in military aviation, pros and cons

Postby brar_w » 20 Feb 2017 22:30

brar_w wrote:Nothing is including RF. So you base your requirements running stealth and counter stealth trades to see how much this needs to influence your design. My point was that stealth aircraft designers do not neglect the IR spectrum and point worth remembering when quoting brochure ranges for IR hardware, just as we assume that a radar range on a brochure would be impacted by RCS. You can't just throw a blanket range number on IR hardware performance without citing what the baseline target represents. Same with radars..if someone throws a radar range you ought to ask yourself, what RCS, which mode etc. In the US they have standardized on 1 sqm targets (RCS) so naturally whatever range figure they cite for one of their radars will become much less if your target has a smaller RCS.

There are designers, operators and testers that are constantly testing low observable configurations and crafts with counter low observable technologies including testing the IR spectrum across the range. Same within the RF. VHF, UHF, L band and bi-static radars are used to constantly probe at low-observable concepts, aircraft and tactics. It just so happens that the most experienced low frequency surveillance radar OEM in the west is also most experienced at producing low observable aircraft.

And it is not just testing after the fact, but actual requirements mandate IR signature suppression. A quick look at the rear half of the YF-22 and YF-23 would show you different approaches vis-a-vis the exhaust gasses. Plus, the F-119 and F-135 approach has been shared here in the past including a photograph.


Just to elaborate on this point since it has consequences and investment paths for the IAF, and the Indian Defense and aerospace S&T community. Modeling, red teaming and constantly engaging in VLO and Counter-VLO testing is an absolute MUST to determine your trades and constantly look at the problem from a survivability perspective. This not only determines how much of these design trades you allow but also helps develop tactics, operational concepts and constructs. Moreoever, you not only have to prototype, model and study your adversaries technology investments but also develop counter capability based on your own technical capacity and system understanding so as to determine potential adversary costs and timeframes to develop counters to the capability you field.

This is to Low Observable technologies vis-a-vis the AMCA development, what creating an eco-system of supplier was to the LCA development effort.. The synergistic effects would be felt on cruise missile design, on the AURA and all future airborne platforms that use some form of signature management. So look as much as what they are developing vis-a-vis design features on the aircraft but also on what they are doing vis-a-vis developing a cold hard understanding of the LO--CLO--equation.

Below are some of the stuff that the US LO/CLO programs have done and/or are currently doing. I had posted it elsewhere but since Shiv started this thread it really belongs here.

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Even before the development of the modern cruise missile, the Soviets had deployed thousands of VHF ground radars for aircraft surveillance and early warn- ing. In 1983 the Laboratory initiated a competitive procurement for a VHF test-range instrument, in order to have an instrumentation-quality VHF radar to investigate the issues associated with low-frequency surveillance. General Dynamics of Fort Worth, Texas, delivered this VHF radar in 1985. It is a substantial but transportable radar featuring a 150-ft-wide an- tenna, as shown in the Figure, and it can emulate Russian VHF radars such as Tall King and Spoon Rest (although it has superior electronic performance). What is particularly interesting, especially for clutter and electronic-countermeasure measurements, is that the VHF instrumentation radar can selectively trans- mit in horizontal and vertical polarizations and re- ceive in both polarizations simultaneously. The radar has undergone a number of modifications and up- grades, including extensive waveform changes and the addition of a sidelobe canceler, to enhance its useful- ness to the test community.
The principal contribution of the VHF instrumentation radar has been the development of realistic appraisals of VHF radar capability against low-observable air vehicles. VHF-radar performance predic- tions are rich in phenomenological questions relating to low-elevation-angle propagation and ground-clut- ter effects, and this radar was a national test bed to ex- plore and define these effects.


Image

More on the Red Teaming -


Generally speaking a red team might ask a series of questions such as the following:
• What are the key gaps in my system or capability that an adversary might exploit?

• What are the countermeasures that an adversary could develop to exploit those gaps and how effective would those countermeasures be?

• How difficult would it be for an adversary to implement the countermeasures?
Would the countermeasures be a 10-line software modification, or would it require building a new system from the ground up?

How much detailed information about the US system does the adversary require to make the countermeasure effective? Does the adversary just need to know our system’s general concept, or would the countermeasure depend on specifics that are classified or otherwise difficult to acquire?

• How difficult would it be for the United States to counter those countermeasures that might be effective? How much information would be required about what the adversary is doing to effectively counter the countermeasures?

The Air Force Red Team is much more than a systems analysis group to explore these questions. Much of the Red Team's work involves the development and testing of prototypes of potential future threat systems. Importantly, these prototypes are not based solely on intelligence estimates of what technologies our adversaries are investing in. Instead, the red team process uses systems analysis to determine the technologies that would result in the most pertinent threat capabilities, and then develops prototypes that could be used to test the real-world impact of those technologies in tactically relevant scenarios. Prototyping and testing alone, however, can rarely be used to explore the full impact of a potential threat in a broad range of tactical situations. Therefore, the results of the testing are used to validate the systems analysis models, which can then be extended to assess a range of relevant scenarios. This integrated program of systems analysis, prototyping, and instrumented testing is the core of the highly successful Air Force Red Team. The real benefit of the analysis in this context is to sort through the large number of potential threat responses and narrow down to the few that are most important. those few can be the subjects of more intensive prototyping and testing campaigns to understand the full impact they might have on our systems.

For each air defense element (surveillance, fire control, missile seeker, and fuze), the air defense can use a variety of sensor technologies, including active or passive radar (radio frequency), infrared, or a range of other less conventional sensors. The unconventional approaches proposed as counter-stealth technologies may run the gamut from acoustics to cosmic rays to gravimeters; however, in each case, it is critical to consider not just whether or not a technology can theoretically detect an aircraft, but whether it meaningfully contributes to the adversary's kill chain. For a number of good physics reasons, air defenses rely primarily on radar and infrared sensors. Compared to infrared, radar has the advantage of offering long-range detection with minimal interference from weather or other environmental factors. It is no accient that the most important long-range surveillance and fire-control systems continue to be active radars. One disadvantage of radar systems is that they are potentially susceptible to jamming, also called electonic attack. Therefore, for as long as air defenses have been invested in radars, aircraft designers have invested in electronic-attack countermeasures to those radars, and, in turn, radar designers have invested in electonic-protection counters to those countermeasures in an endless cycle. The key on each side of the cycle is to invest in technologies that are as robust as possible to the other side's likely response.




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