LCA: News & Discussions - October 2016

Dileep · Post by **Dileep** » 07 Apr 2017 07:17

JayS wrote:
Dileep wrote:The story of gun vibration is quite interesting you see..

Marten, I am still sticking to my prediction on FoC date.
Despite hints dropped by Tejas FB page, Livefist and SJha about good new coming soon..??

Yes, despite that. I would be the happiest person to be proven wrong.

shiv · Post by **shiv** » 07 Apr 2017 07:28

Came across this while searching for info. It is open and public, hence posting:
https://www.postjobfree.com/resume/acwf ... delphia-pa

Design Engineer, Deputy Manager
Location:
Philadelphia, Pennsylvania, United States
Posted:
September 01, 2016
Email:
[email protected]

Contact this candidate

Akshay Sriraman

Managed GSh-23 gun integration project on Tejas PV3 - strain gauge/vibration/RPM measurement of chain belt Design Engineer (FTC, ARDC) Hindustan Aeronautics Ltd. (India) Dec 2008 – Dec 2012

§ Developed a digital video transmission system for Tejas using kWorkbench and integrated Airborne Separation Video System (ASVS) to analyze stores’ (1000 lbs. MK-11 bombs and R-73 close-combat missiles) separation

shiv · Post by **shiv** » 07 Apr 2017 07:39

I have a hard copy of this photo and it is possible that the BR image is one that I scanned. MiG 21 from around the time of the 1971 war

It shows a GSh 23 in an underslung gun pod

Larger Image

The gondola carrying the GSh 23 is a standard fitment that has been used underwing for helicopters as well

I suspect this weapon will get integrated onto the Tejas ithout too many issues barring the point raised by Dileep about nearby LRUs

shiv · Post by **shiv** » 07 Apr 2017 07:44

Incidentally I also found this hack idea to reduce resonating frequencies
https://www.bevfitchett.us/heavy-machin ... -guns.html

Incidentally, it is useful to be able to vary the firing rate in helicopter installations in order to avoid resonant vibration frequencies, which affect accuracy.

Aditya_V · Post by **Aditya_V** » 07 Apr 2017 07:50

Only question Shiv, how much on that CV is actually true, the person claims to be integral to LCA and then developing software for EVM's. I mean does anyone work on structural engineering, communication/ video transmission systems in LCA/ Defence (I thought both would require different skills) at the same time then have an opportunity to devlop software for EVM's. and does an engineer who passed out in Jul 2008 get to "Manage" GSH-23 gun integration between 2008-12? When he claims to have worked as "Deputy Manager- Design" in HAL from Jan 2013 -Jul 2015.

Even to a commerce student some of this looks a bit made up. Reading his CV he looks like a one man army who has done it all.

shiv · Post by **shiv** » 07 Apr 2017 07:53

http://weaponsystems.net/weaponsystem/H ... PK-23.html
GSh pod on a MiG 27. The fixation to the pylon does not look (to my dentally challenged eye) as if it is required to take high levels of vibration.

Introduction

The UPK-23 is a late Cold War era basic and powerful gun pod of Soviet origin. It was developed in the 1970's to provide the Mi-24 Hind attack helicopter with more firepower and can be used on most fighter aircraft as well. The UPK-23 sometimes referred to as the UPK-23-250 with the number 23 denoting its 23mm caliber and the 250 being its ammunition capacity. The name UPK stands for Unifitsirovannyj Pushechnyj Kontejner, which is Russian for universal gun pod.
Design

The UPK-23 is a gun pod of a fairly simple design. The round aerodynamic pod houses a single fixed twin barrel GSh-23L autocannon at the front and associated ammunition at the rear. For operation the pod requires external power which is provided by the aircraft. Since the cannon is fixed it is aimed by pointing the aircraft in the direction of the target. Compared to the SPPU-22 pod with similar but flexible armament the UPK-23 is much lighter.
Firepower

The UPK-23 features a single twin barrel GSh-23L autocannon and 250 rounds of 23x115mm ammunition. The cyclic rate of fire is 3.000 rpm and the maximum effective range is 2 km. The 23mm rounds are effective against infantry, soft skin vehicles and light armored vehicles.
Users

The UPK-23 is most commonly found on the Mi-24 Hind attack helicopter and armed version of the Mi-8 Hip transport helicopter, but is used ground attack fighters such as the Su-17, Su-25 and MiG-23 as well. For fixed wing aircraft the slightly heavier SPPU-22 gun pod with flexible armament usually is a better option. The UPK-23 remains available although it is unknown if these are newly produced or refurbished pods.

shiv · Post by **shiv** » 07 Apr 2017 07:55

Aditya_V wrote:Only question Shiv, how much on that CV is actually true, Reading his CV he looks like a one man army who has done it all.

Yeah the CV reads like tech depends on him. OTOH hand I keep telling some young low self esteem people that they must make their CVs look good.

ramana · Post by **ramana** » 07 Apr 2017 09:36

His background and education is electronics. All his tasks are in that area. Installing strain gages to measure structural response and measuring system.

Gagan · Post by **Gagan** » 07 Apr 2017 09:41

I mean it is a pod, and will hang by the two hooks onto the pylon which is pretty standard.

Won't the gun in the body have appropriate shock absorbing chassis on which it is fitted? Surely it is not too difficult to reduce the vibrations to acceptable limits.
Also won't LRUs be mounted on shock proofed structures themselves, considering this is a fighter aircraft which will land hard and fast even on semi-prepared runways? The LRUs must be defence grade too.

I once had a laptop which was drop proof from a height of 1m or some such. They mentioned that the chip and HDD were mounted on a shock proof chasis or something like that.

shiv · Post by **shiv** » 07 Apr 2017 10:07

Gagan wrote:I mean it is a pod, and will hang by the two hooks onto the pylon which is pretty standard.

Won't the gun in the body have appropriate shock absorbing chassis on which it is fitted? Surely it is not too difficult to reduce the vibrations to acceptable limits.
Also won't LRUs be mounted on shock proofed structures themselves, considering this is a fighter aircraft which will land hard and fast even on semi-prepared runways? The LRUs must be defence grade too.

I once had a laptop which was drop proof from a height of 1m or some such. They mentioned that the chip and HDD were mounted on a shock proof chasis or something like that.

While I don't know the exact answer to this - I am simply guessing that any recoil/vibration absorption mechanism will have to take the energy from the recoil and pass it off to a chassis or some other structure. But since they are connected then both gun and recoil damper will shake and dance making the gun inaccurate. I don't know how this is handled.

When I watch clips of large guns like Bofors firing there is this huge recoil absorbing hydraulic mechanism and the barrel goes backwards into that. But still the entire weapon jumps and a cloud of dirt is disturbed at the gun anchor points

Gagan · Post by **Gagan** » 07 Apr 2017 10:20

Accuracy from a fighter aircraft mounted gun is relative.
Can't expect these to have a sniper level CEP.

The platform is moving fast, and will usually line up in the direction of fire, no lateral movement (a roll is OK, but no sideways movement) as this will make targeting more challenging and unpredictable.

Gun firing usually starts short of the target and continues in a straight line, until the projectiles are hitting the target

JayS · Post by **JayS** » 07 Apr 2017 11:44

rohitvats wrote:
JayS - If others designed their outer pylons to carry some in-service load (beyond only the short-range AAM), why did we not do that in case of LCA? Forget margins for anything, that pylon did not have capacity to host anything than R-60. Was such a limitation a trade-off between some aspect of wing/air-frame designing+manufacturing? You'd know the answer.

Mirage-2000 outer pylon can take 300 kg load while Mig-29M has 500 kg capacity. I'm willing to be corrected but both carry only AAMs. This load capacity is much more than in-service CCMs that these types could carry when they entered service. So, someone made provision for carrying higher-payloads from word go.

If it is poor foresight, that is one very serious fore-sight.

Rohit,
I don't know answers with 100% confidence. I can merely speculate based on logical/plausible arguments. I really wish some retired folks from ADA right a book or two on LCA development.

Two points -
1. Why LCA designers did not design the outboard pylon to take up other weapons like in some other aircrafts..?

As I mentioned in my previous posts, apart from M2K, all other jets were designed to carry something like 250kg bombs on the outboard pylons. Thus they obviously could accommodate the increasing weights of CCM. But it is wrong to say then that the designers kept deliberate margins to accommodate future growth and use them as example to show LCA designers didn't show the same wisdom. But there are other contemporary jets such as Gripen/Rafale which have wingtip pylons designed for barely holding CCMs. So its possible that LCA designers chose one philosophy over the other keeping all factors in mind.

IMO the simplest explanation why jaguar, MiG21, Harrier etc had outboard pylons stressed for 250kg or more from starting itself is perhaps the limited number of pylons - 2 per wings. (Even M2K has only 2 pylons per wing, but 5 fuselage points compensate things nicely). Only MiG29 had 3 pylons per wing initially itself, but it looks like they envisaged full-fledged short range A2G role for it from starting. With limited pylons obviously it would have been a severe disadvantage if outboard pylons were designed only for CCM. While for LCA, the designers might not have felt the need to do so due to availability of 4 wing pylons + 2 fuselage pylons even while keeping outboard pylons exclusively for CCM. The total designed weapons load was 3500kg only anyway. And perhaps bomb-truck role was never envisioned for LCA, but mainly A2A and limited A2G capability was asked for. If they did not feel the need, there was no point overdesigning outboard pylons for loads like 300kg. In all above examples only M2K has close resemblance to the wing design of LCA. All other jets have smaller moment arm for outboard pylons as compared to LCA. (don't just compare distance from centreline, look at the overall design. For example, for MiG-21 the LG is attached to wings and the pylons are quite close to this point which must be a beefed up structure. For MiG29 the wing attachment point is quite a lot outwards from centerline, effectively reducing pylon - wingroot distance, which is what matters in design. For Harrier, there was outrigger wheel at wingtip, which might have been the critical load case for the wing already and not the outboard pylon).

OTOH it could have been as simple as designers being totally clueless about keeping such margins while designing, just as IAF was clueless about next generation AAM weights while specifying 1985 ASQRs.

2. Why LCA designers didn't keep enough margin while still designing it exclusively for CCM.

Do we know for sure it did not have any/very little margin..?? For all we know LCA perhaps had a lot of margin over its design intent of R60's 45 odd kg (doesn't necessarily mean it was designed for only ~50kg, could be 90kg also. Who knows if we had procured AIM9X instead, redesign might not have needed). A 2.4x weight jump was too much for it to accommodate and as Tsarkar noted, perhaps the designers took a call post 2005 and decided to redesign for 150kg so as to accommodate R73 and have sufficient margin for future growth at least after they realized the error. We may never know the truth though. I agree to one thing that Tsarkar pointed out - why LCA was not designed keeping in mind coming generation of CCM. Thats a valid question. There seems to be a lapse there. Who was responsible for the lapse, we could discuss endlessly without any conclusion. Hindsight is 20-20 and its easy to say what was done was right or wrong now. Had the LCA designers over designed the pylons making wings even more bulkier and empty weight even higher and R73 never materialized for whatever reasons or next generation missiles weren't so much more bulky than the R60, we would be cursing them for over-design. We do that for NLCA's MLG for example. We do blame the designers for exceeding intended empty weight target.

I can think of many points which should be considered before saying LCA designers seriously erred. While we want LCA to be comparable to the best in the world, our designers do not have tools, technology and experience to do so, at least not for LCA. You know how we say our missiles are too heavy as compared to their global counterparts in the same category because of lower Isp of our propellants..? I am sure our composite technology (I am pretty sure on Composite design methodology at least if not the actual composite materials) is similarly lagging the best in the world and thus LCA is overweight. I have previously tried to explain in one long post why we could have ended up with considerable overweight airframe for LCA.

Also even though it might be a serious lapse, its OK that it happened. Much more experienced OEMs screw up things routinely in Aerospace. F104 which came up in some posts above is one good example. What matters is how you deal with it. I always say, a good organization is not necessarily the one which never screws up, but the one which can handle screw-ups in proper manner. Here the Program management skills come into picture, which we seriously lack as far as managing an Aerospace project of such magnitude is concerned. Another issue is everyone is seating on the edge - IAF cannot wait indefinitely to have aircrafts and DRDO cannot afford to make below par product which will be shown doors very easily. There is little room for error for both sides and thus things get edgy, IMO.

Gyan · Post by **Gyan** » 07 Apr 2017 12:23

A query to experts:- Is it possible that outermost Pylon of LCA is "deemed" to be weight restricted as the IAF requires and specifies higher manoeuverability ie higher Gs for LCA with CCM on outer pylon. For instance IAF may require 5Gs while U.K. May require 3Gs from Harrier/Jags when fully loaded.

JayS · Post by **JayS** » 07 Apr 2017 13:10

tsarkar wrote:
Now, I research extensively before posting, ask knowledgeable people, double check on the internet, to ensure my posts are factual. I'll be happy if anyone points out any mistakes in my posts.

The reason I write harshly occasionally is because of outright lies, like unreasonable user changed specs, when so many legacy and current aircraft are concurrently getting AAM & other upgrades without structural design & build changes and rona dhona. Or Mirage 2000 not being a CCV or had AAMs. Or ships being like whales and crumbling.

The question I ask you & forum members what is the Forum's re-course to address dishonesty?

A person blatantly lies Mirage 2000 not being a CCV and did not have any missiles. That lie supports beliefs held sacred here. So should the lie be allowed to propagate?

What happens when forum members meet better informed people in the real world and tell them,"Mirage 2000 not a CCV and didn't have missiles" or IAF "unreasonably added R-73E"? Wont they be making utter fools of themselves? What happens to the credibility of the forum & its members?

Time challenges did not allow me respond & complete some of the earlier discussions.

I mentioned earlier that a BVR missile and its carrier aircraft need to have their respective envelopes sync up via testing to ensure better Pk.

A member responded that just ensuring safe clearance of missile and guiding by radar is good enough and IAF is needlessly insisting on extensive testing.

Its the bloody user's problem of maximizing Pk.

Such logic will do wonders for export potential of Tejas. Tell export customers that the missile drops and clears neatly and guides by radar. Export customers can figure out themselves maximizing Pk.

Potential Tejas customers, countries like Vietnam, that buys approx 40 aircraft a decade, and lacks instrumented ranges - will be overjoyed to hear this export pitch. They're a small country with limited resources facing a large aggressor. Every bit of effort is focused on countering the aggressor.

They will be overjoyed on learning they will need to spend more money than the cost of planes + missiles in building an instrumented range to mate missile & aircraft performance envelopes to maximize Pk. And do it again when the missile becomes obsolete in a decade.

And after such brilliant logic, the forum will then wonder why indigenous equipment doesn't sell anywhere, and come up with more conspiracy theories.

I rest my case, and excuse myself humbly apologizing to all.

I cannot agree more to the last part regarding the extensive testing needed to sort out all the bug and the point you raise related to export customer. It should not be passed over. Our problem is not that we test too much. Our problem is that we want finished product right in the first iteration. The need of the hour is to lower the bar, don't expect ab initio developments to kick asses of contemporary best in class products. Let the less than perfect (but safe and easy to use) be inducted atleast in small batches so that the designers get the chance to see how it performs in the field and tweak the product accordingly to improve it. Using the product first hand gives the user himself also the chance to give better feedback. Of coarse its will be little painful in starting for the user, but soon the pain will give a lot of gain. Its like an equity investment, which gives much better returns in long term, even while giving loss in short term, if you stick around. The kind of products we are talking about here are the ones which the user that it our soldiers will be using for decades, and their life depends on them. We are not talking of an I-phone which can be exchanged for better one in one year. The Armed forces need to be fully invested in the defence equipment development. As I said before in another post, there are two extremes:

- The customer doesn't know what he wants.
- The user knows exactly what he wants and he defines the product and the future road map for it.

I ask you this question. Which side does our forces want to be leaning towards...?

My observation is - Average soldier has much less appreciation for technology development process and the long process from an idea to a lab prototype to real life application. An average engineer is equally ignorant to the operational requirements that a product needs to have in order to be at its best in the field on daily basis. Both of them have more important things to worry about in their daily lives than the things that the other side cares about, so they naturally tend to focus on them. This gives rise to a huge gap between what is expected by the user and what the designer delivers. While this kind of situation is ok for something like a Mobile phone industry or automotive sector, its not at all ok for MIC. And while its OK for majority of soldiers or designers to be ignorant to other side, the top brass from both the organisations cannot afford to be of that mentality. IMO, the best way to bridge the gap is cross-pollination of people between the two sides. We see a lot of Armed forces personnel deputed to HAL/DRDO or retired soldiers joining the RnD establishment. Why don't we have DRDO folks going to Armed forces and work on the technical matters there..? For example why can't we have DRDO scientists deputed to IAF when IAF defines future requirements or work out technical plans for next upgrade..?? (Do we already have such arrangement..? Let me know if its there already, I have not seen it so far.) Another thing I suppose would help Armed forces to be able to take part more closely in the product development is to have own design and RnD wings manned by personnel from engineering and sciences background who are hired to be nerds in uniforms. I recently visited an IAF base and it was quite an interesting experience for me to know the other POV on certain things. There was one type of data that IAF units collect on daily basis which is used only for keeping operational status in check but the same data can be invaluable to designers in next iteration of designs perhaps 10-15yrs down the line and IAF is the only source for them, no other AF in the world will share that data obviously. The IAF person there had no idea if someone in IAF was compiling that data in useful manner and sharing with DRDO or HAL or not. This kind of close collaboration is possible when the two side get to know each other well. And that only possible when you let them mix with each other. We don't need each and every one of 2million personnel from Armed forces to be tech savvy, but only a small section and majority of top brass who at least have due appreciation for technology development if not intricate understanding. Likewise for RND establishment, top brass who frames policies and direction needs to have people who understands that Operational requirements need to be given upper hand rather than technology development in time-critical projects. Its little easy for them to do this, simply by putting armed forces personnel in key posts - like Cmd Balaji was heading LCA, or Cmd Mao was leading NLCA development. Its little difficult IMO for Armed forces, particularly the IAF and IA to change the organisational thinking. If they start now it will take a while to have effect for sure. But they need to start. They also need to start funding futuristic technology related work in academia/labs to see if it can solve some issues they have or they can use the technology somehow in coming future.

There will always be a gap in thinking of an soldier and a weapon designer (or an user and a designer in general, you will see this gap in every single field). We can minimize it but not eliminate it. And there will be organisational egos coming in the way from letting people work in ideal manner, even though we may not like it. That's why IAF needs to care which pylon and why and not leave everything to the designers. You cannot say user doesn't care which pylon it was to be mounted. Majority (like 99.99%) of IAF cadre can remain ignorant but not IAF as an organisation cannot. IAF needs to have people in it who are hired exactly to do this - to care for such things for IAF (likewise for IA. DRDO/HAL already take in personnel from armed forces, they can increase the numbers even further too). You can blame designers all you want for not seeing the future, but you have to accept that IAF failed to see it too..!

Karan M · Post by **Karan M** » 07 Apr 2017 13:30

^^ when asked about why LCA had some specs, the IAF guys pointed to the Mirage 2000 manual which they had got from France just before. Some of these "transferred" specs worked out, some didn't. That's what happens when you don't have a comprehensive policy of your own and cobble together "best in class" of what's available to you. for instance, in 2003 ? i guess, when asked about what BVR on LCA, we were pointed to Super 530 D, R-27 style missiles. by then ARH were already in induction and later, were adopted. point is that stuff keeps evolving, sometimes you can accomodate it and sometimes you can't. in 20010, there was much talk of kopyo now being suited for the LCA. IAF CAS even made the point that it was better than the radar on Mirage 2000. now we know via CAG and media leaks, the Kopyo doesnt work in A2G and the R77 has been suboptimal in batches. so there went that plan. in 2014 or thereabouts, IAF finally got a Bars radar that met its specs (Bars was in production since 2001). fact is it's rare we get any import that works perfect in first version or is as tested as our indian products are.
much talk about F/A-18 E/F superiority: well, this 7.5G limited fighter (LCA does " onlee"

is having this minor issue onlee.

https://theaviationist.com/2017/03/29/a ... on-issues/

so much for services relying on "proven" imports.

meanwhile, here are some world renowned designers and their "program skills" and "foresight"
http://finance.yahoo.com/news/price-tag ... 04003.html
http://www.pogo.org/straus/issues/weapo ... conclusion

Another structural issue yet to be resolved on the F-35C involves the wings. During test flights, engineers discovered the ends of the wings were not strong enough to support the weight of the AIM-9X short-range air-to-air missile. The F-35C’s wings fold at the ends to save space in the crowded confines of the deck and hangars on aircraft carriers. When the missiles are carried past the wing fold, the weight exceeds structural limits when the plane maneuvers hard and during landings. According to DOT&E, until the problem is corrected, “the F-35C will have a restricted flight envelope for missile carriage and employment, which will be detrimental to maneuvering, [and] close-in engagements.” It’s more detrimental, even, than the F-35’s other inherent maneuvering limitations. The problem is bad enough that Lt. Gen. Bogdan has admitted the F-35C will need an entirely redesigned outer wing.

Aircraft taking off from the confined decks of carriers require a major boost to reach the necessary speed to achieve lift and takeoff, which is accomplished with a catapult set into the flight deck. Before the jets are launched, the pilots increase the engine thrust. To keep the jets from rolling off the front of the ship before launch, they are held down with hold-back bars. The force of the thrust compresses the gear’s strut as it is being held down. When the hold-back bar is released and the jet is launched, the F-35C’s strut is unloaded, causing the nose to bounce up and down, jarring the pilot according to a Navy report that was leaked to Inside Defense in January 2017.

It took the crew 55 hours to complete the engine swap, far longer than it takes to perform the same action on a legacy aircraft. The engine on an F/A-18, for instance, can be replaced in 6 to 8 hours. DOT&E noted the crew took its time performing all the necessary steps for safety purposes, and pointed out that future iterations would likely be a little faster as the crews gain more experience. That said, the crew had full use of the entire hangar bay space, something they wouldn’t have with an air wing embarked on the ship. This likely sped up the process during this demonstration. Replacing the engine in the F-35 is more complicated than in an F/A-18. Crews must remove several more skin panels and a large structural piece called the tail hook trestle in order to remove the engine, thus requiring more space in the maintenance hangar. These parts and all the tubes and wires associated with them must be stored properly to prevent damage, also taking extra space. The maintenance crews must perform this process with a full air wing present in order to know whether the system is operationally suitable. And the process must become significantly more efficient to generate the sortie rate needed for combat.

As the program moves out of the easy part of the testing—the development or laboratory testing—and into the critical combat (operational) testing period in the next few years, even more problems will be uncovered. A good example occurred in late 2016 when engineers discovered debris inside the fuel tank of an F-35. Upon closer inspection, they found that the insulation wrapped around coolant lines had disintegrated because a subcontractor failed to use the proper sealant. And, when the GAO estimated it would cost $426.7 million to fix some of the known problems in the F-35As already in depot, the coolant line insulation problem had not been discovered. Fixes to this and other problems will all have to be devised, tested, and implemented throughout the fleet of aircraft already produced and purchased.

Another time-consuming process involves adding new aircraft to each ALIS standard operating unit. Every time an F-35 is moved from one base to another where ALIS is already up, it must be inducted into that system. It takes 24 hours. Thus, when an F-35 deploys to a new base, an entire day is lost as the data is processed. And only one plane at a time can upload. If an entire squadron, typically 12 aircraft, needed to be inducted, the entire process would take nearly two weeks, forcing a commander to slowly roll out his F-35 aircraft into combat.

The scale of the challenge yet remaining with the F-35 is easily quantified in this year’s DOT&E analysis. According to the report, the F-35 still has 276 “Critical to Correct” deficiencies—these must be fixed before the development process ends because they could “lead to operational mission failures during IOT&E or combat.” Of the 276, 72 were listed as “priority 1,” which are service-critical flaws that would prevent the services from fielding the jets until they are fixed.

Much has already been made about the F-35’s shortcomings in combat, yet structural problems still remain with the basic airframe. An example of this is a failure of an attachment joint between the jet’s vertical tail and the airframe. This has been a persistent problem, as the shortcoming was discovered in the original design. Engineers discovered premature wear in a bushing used to reinforce the joint during early structural tests in 2010. The joint was redesigned and incorporated in new aircraft in 2014. In September 2016, inspectors discovered the redesigned joint had failed after only 250 hours of flight testing—far short of the 8,000 lifetime hours specified in the JSF contract.

Then there is the matter of pilots actually seeing double due to “false tracks.” There is a problem with taking all of the information generated by the various onboard instruments and merging it into a coherent picture for the pilot, a process called sensor fusion. Pilots are reporting that the different instruments, like the plane’s radar and the EOTS, are detecting the same target but the computer compiling the information is displaying the single target as two. Pilots have tried to work around this problem by shutting off some of the sensors to make the superfluous targets disappear. This, DOT&E says, is “unacceptable for combat and violates the basic principle of fusing contributions from multiple sensors into an accurate track and clear display to gain situational awareness and to identify and engage enemy targets.”

...

take the indian testing anyday over such "proven" imports which will be debugged at our expense over decades.

Karan M · Post by **Karan M** » 07 Apr 2017 13:34

btw, the fa-18 issue? minor problem of hypoxia only. f-22 also had it.

no problem. don't fly as much. or high. or this or that...

meanwhile our "desi products" are in news for "3-legged cheetah" while of course, these imports get fawning editorials in all the press and from rtd bigwigs talking about how they are "essential for superiority" vs TSPAF or PRC or whatever.

negi · Post by **negi** » 07 Apr 2017 14:55

Harrier and LCA comparison is so wrong at so many levels ; just doing a payload to payload comparison does not mean anything , two completely different AC with completely different mission profiles and even flight envelope I am not sure how can both be compared .

Elephant in the room is we started with 'small' and 'compact' platform this fundamental fact by nature will always be a limiting factor when it comes to need for hauling up additional load be it on wingtip or underbody. MKI can today haul up Brahmos because the platform was big enough with margins for growth.

Now that we have luxury of hindsight if you look at Arjun and the LCA the glaring difference in terms of philosophy and it's repercussions are evident i.e. Arjun is literally future proof , if you need to mount a L55 on it tomorrow it will be able to accept that for it started with a big and wide platform , if you want to swap out the engines with something in Leo2A5 class I think that might be doable . The same however cannot be said about a small platform like LCA , the F-16 went through mutliple iterations because it had a beast of an engine all those CFTs and additional hulk in the Block 60 still does not relegate the AC from it's air superiority role. When USA replaced the F-14 with F-18s they made a significant compromise a gap which could not be bridged until much larger and hence much capable SH was introduced .

JayS · Post by **JayS** » 07 Apr 2017 15:00

I wish to see IAF defining its own concept of 6th generation fighters and then Indian scientists making it happen. And not just we copying American or Russian concept of how 6th Generation looks like. But time is running out fast and we are nowhere in the scene.

srai · Post by **srai** » 07 Apr 2017 15:31

^^^
That's when India will come of age do to speak. It would become technology and military leader in the world where other countries look up to it for new ideas/innovation. For that to happen, R&D along with all the supporting institutions/industries need to be aligned and funded adequately for the long term. Mindsets need to change as well.

brar_w · Post by **brar_w** » 07 Apr 2017 15:35

negi wrote:When USA replaced the F-14 with F-18s they made a significant compromise a gap which could not be bridged until much larger and hence much capable SH was introduced .

The replacement for the F-14 was the E/F variant of the F-18. Still it never replaced the mission as is but the mix of missions the F-14 performed were reorganized to de-emphasize some of the missions it had been optimized for in the post-SU collapse environment. Had the cold-war not ended there was no way the Admirals could have justified replacing the Tomcat with the Rhino..It would have been either the super-tomcat or the N-ATF given the Soviet bomber, cruise missile and fighter threat to the CBG.

JayS · Post by **JayS** » 07 Apr 2017 15:39

shiv wrote:I need to ask a question. If a pylon is designed for 70 kg because it is an outboard pylon that will tend to bend and break off the wing at high G-forces if 100 kgs are loaded - what "future weapons" has it been designed for.

This is a "Have you stopped beating your wife" question. If a pylon can take only 70 kg, it can take only 70 kg. Future weapons will have to be designed to fit loads that do not exceed 70kg. For example the American copy of the Chinese J-20 (called the F-35) needed to have new weapons designed for its internal bay - namely the SDB.

So what is stopping India from developing a 70 kg close combat missile?

(Let me first say it upfront that I do not know what there was significant weight increase from ~43kg to >100kg, when one would expect the newer generation to have better performance in same or lesser weight or at the least have marginal increase in weight over previous generation. American or French OEMs do not seem to have such significant increase in weight over the generations.)

In my opinion, It would be rather foolish to expect our scientists to come up with an AAM of comparable performance of the other contemporary missiles while being significantly lighter. Especially when our technological competence is lagging and thus we could either get same performance in heavier missile or less performance in same weight class in a reasonable time and resources. Of coarse we should start a program to create better performing missile in lesser weight, but that should not be tied to LCA then. Because then the operational readiness would take a hit in case the project gets delayed due to significantly steep objectives and leave LCA stuck with R60 for a long time. What is more practical is to consider same weight class as other AAMs have (current and one generation next) and then keep some margin over it and then design the pylon for that. Looks like if Russians could have managed to keep the weight increase similar to the Americans or Europians, we would not have had issues with LCA as well. Damn Russians screwed up.

But after going through a lot of stuff in last two days, one question is left in my mind - While R73 development started in 1973ish and it was already operationalized in 1984 (thank you wiki kaka), why our 1985 ASQR for LCA did not specify R73 (or Magic-1 which was already operationalized by then and was with us already or was coming soon through our M2Ks) as possible replacement as AAM on the outboard pylon..?? Or the ASQR mentioned them as requirements but ADA failed to fulfil these requirements..?? We might never know.

JayS · Post by **JayS** » 07 Apr 2017 15:39

srai wrote:^^^
That's when India will come of age do to speak. It would become technology and military leader in the world where other countries look up to it for new ideas/innovation. For that to happen, R&D along with all the supporting institutions/industries need to be aligned and funded adequately for the long term. Mindsets need to change as well.

Yeap. But we have missed the bus for 5th generation and I might not live to see 7th generation jets flying (they might be coming with chameleon skin anyway so no one might see them really ..

), so I put my hopes on 6th Gen.

JayS · Post by **JayS** » 07 Apr 2017 15:49

geeth wrote:Guys,

Some really new gyan I am learning from this thread...

Because, all this while I was thinking that it is the structural strength of the wing that determines the weight that can be slung at the tip according to flight conditions and not the otherway round! At the most the designers would check whether the to-be-used missile conforms to the design limits. Otherwise, why would the LCA fly with a dummy missile during test flights? (So that the wing deflection is not too much affecting the aerodynamics of wing in that particular weight distribution?)

IMO even if a situation arises wherein a heavier wingtip missile has to be used, they still can do it by slinging lighter loads in the inner pylons. Actually the permutations and combinations are many if you consider the fuel weight at various times of flight. I am sure the designer considers all these.

Actually each pylon is rated for certain load, and one is not expected to go beyond that weight. Even though the wing as a whole might support higher weight than the rated value under some weapons load configuration, the local structure holding the weapon at that pylon may not, unless it is designed for higher than the nominal rated capacity. In theory OEM could certify the wing for variable load on pylons based on various load-outs but then you will have to simulate and test far more load cases in all those permutations and combinations which is a significantly large effort (and one which will have to be repeated with each change). And then the AF will have to be given more complicated instructions on weapons loads and make sure they are followed every time without fail.

What I think is it has practically very limited value to have too many P and C. The efforts are not worth the gain. In practice the aircraft will follow much more laid down path with only rarely requiring to deviate from the usual practice. And even rare would be situations which cannot be solved relatively easily with some other simpler solutions like increasing sorties or using alternate, more capable platform for example.

Karan M · Post by **Karan M** » 07 Apr 2017 15:57

Negi, that future proof Arjun is too heavy for the IA. Perhaps we need to put a cannon in a pod for the LCA and sell it to IA as lighter than T-72 MBT and sell the Arjun to AF as Brahmos capable heavier than MMRCA class. See, problem solved!!

brar_w · Post by **brar_w** » 07 Apr 2017 15:59

While I agree with the notion that designers do leave room to grow when it comes to weapons load sometimes if unchecked they can go a little over the top

JayS · Post by **JayS** » 07 Apr 2017 16:11

brar_w wrote:While I agree with the notion that designers do leave room to grow when it comes to weapons load sometimes if unchecked they can go a little over the top

kit · Post by **kit** » 07 Apr 2017 16:42

brar_w wrote:While I agree with the notion that designers do leave room to grow when it comes to weapons load sometimes if unchecked they can go a little over the top

.. what the heck was that ?!

Karan M · Post by **Karan M** » 07 Apr 2017 16:47

Comrade! We hab solution!

Future proof Arjun/future proof LCA. You decide.

kit · Post by **kit** » 07 Apr 2017 16:54

Cain Marko wrote:
vina wrote:
Ah, is outboard pylon of Harrier == Outboard Pylon of LCA ?

Harrier Wing Span - 7.6m ---- Tejas Wing Span - 8.2 m

Outboard Pylon of Harrier == MIDBOARD Pylon of LCA.
Outboard Pylon Harrier - 450Kg capability --- MIDBOARD Pylon of LCA - 1000 Kg (I think 1200Kg)
Outrigger Wheel of Harrier === Outboard Pylon of LCA - == 250KG (good for dual pylon IR missiles)

So if we want to see "adequate margins in design " , add a wingtip staton on the Harrier like we see in the Gripen, F16 and SU -30 , put in a 250 Kg missile there and then talk.
Other wise, I will put in a 10 Rack CCM on the Midboard of LCA or, 3 rack of 500 Kg in LCA mid board and claim victory and "strategic upper hand".
Have a nice day.
ps:
Does it matter where you hang stuff from ? Pliss to see .

(this one has answers on why it is so)
Dunno how this works or what it proves, my nephew could easily lift the chairs.... I couldn't though. We are the same height. Seems that age plays some role?

Best explanation for chair lifting "experiment"

This was a trick created by a woman. If a man & woman are the same height, the mans feet are longer, this creates a greater space between the wall and the body compared to the woman, so when he backs up 3 steps, he is on his tippy toes, compared to the woman who is flat footed. When he places his head to the wall, the man has already fallen over but the wall is keeping him on his feet, he can not get back on his feet EVEN WITHOUT THE CHAIR, so the chair is an illusion. This is about the man losing his balance, not strength, because his 3 steps back put all of his body weight on the tips of his toes and again, the woman is flat footed, where all her body weight is evenly distributed throughout her feet. NOTICE THE MANS HEELS ARE NEVER ON THE FLOOR WHERE THE WOMANS ARE. The chair only plays a factor when men that have smaller feet, may not have completely fallen over when he leans his head on the wall, he will lie at an even balance, but when he picks up the chair, the weight of the chair tips him over and he no longer standing, he fell over and his head against the wall is keeping him up, but no one knows that, so he has the illusion of standing on his feet when all of his body has toppled over forward and the wall is keeping him from falling over foward.
In 99% of the cases, if a man removes his shoes, then backs up 3 steps, the extra 3 inches that this will bring him closer to the wall will allow his feet to be more flat footed, where he is not toppled over, and will be able lift the chair and be able to maintain his balance to stand upright. This is an illusion balance trick that was created most likely by a woman that kept it to herself and died with the secret.

JayS · Post by **JayS** » 07 Apr 2017 16:55

kit wrote:
brar_w wrote:While I agree with the notion that designers do leave room to grow when it comes to weapons load sometimes if unchecked they can go a little over the top

.. what the heck was that ?!

F15 carrying F-16 of Lilliputian Air Force...!!

shiv · Post by **shiv** » 07 Apr 2017 17:31

Gagan wrote:Accuracy from a fighter aircraft mounted gun is relative.
Can't expect these to have a sniper level CEP.

The platform is moving fast, and will usually line up in the direction of fire, no lateral movement (a roll is OK, but no sideways movement) as this will make targeting more challenging and unpredictable.

Gun firing usually starts short of the target and continues in a straight line, until the projectiles are hitting the target

. Unless the gun is stabilized a spray of bullets can be useless. If the spread of shells is too much the gun will be useless. Even at 60 rounds per second, a 0.25 to 0.5 second burst at a target 500 meters away a spread of just 1 degree of an arc off center will place less than 1 shell per square meter of target surface visible in the gunsight. I had mentioned the story earlier related by a helo pilot testing a gun who said (in jest) that it would spray a circle of bullets around the target and none would hit the target - so that a man sitting on the target would be perfectly safe

Marten · Post by **Marten** » 07 Apr 2017 17:48

Karan M wrote:Comrade! We hab solution!

Future proof Arjun/future proof LCA. You decide.

I have tears running down my cheeks. Folks around are wondering if finally Fridays have gotten to me!
This will work! We need to add two Brahmos on the outer-most pylons to make this a complete offering.
And if you can add the label Made in <non-India>, the sales pitch is done!

shiv · Post by **shiv** » 07 Apr 2017 17:50

brar_w wrote:While I agree with the notion that designers do leave room to grow when it comes to weapons load sometimes if unchecked they can go a little over the top

Ah the American copy of the Chinese J-10 being carried by the American copy of J-11

JayS · Post by **JayS** » 07 Apr 2017 18:00

Marten wrote: PS: If the wingtip didn't matter, they wasted three to five years overall instead of simply working on multiejector racks. Why? Would be happy to learn.

Had they not redesigned the wings we would be in a situation where the outboard pylons were unusable completely unless we wanted to keep using R60 (and assuming the pylons could not have taken any other lighter missile like AIM-9X, for example), effectively reducing the number of pylons to 6. While it might have worked for A2A role, in A2G role LCA would have had no CCM with it in most of the configurations.

shiv · Post by **shiv** » 07 Apr 2017 18:18

JayS wrote: IMO the simplest explanation why jaguar, MiG21, Harrier etc had outboard pylons stressed for 250kg or more from starting itself is perhaps the limited number of pylons - 2 per wings. .

The MiG 21 in its first iteration had just 2 wing hardpoints to carry either two AAMs (K-13 ) and no gun. One rocket pod per hardpoint was an alternative loadout and that may have been about 150-200 kg. It was a long time before the 4 wing hardpoint MiG 21 came out. The 1971 war was over by then. Belly tank was always an option - replaced by the GSh 23 gondola later.

The Harrier was developed as a veritcal takeoff aircraft for ground attack in the era when it was expected that the USSR would take out all European air bases. That would still allow Harriers to operate from small clearings. So the Harriers pylons were always designed for at least 500 lb bombs.The rolling carrier take off idea (Sea Harrier) was a later development. The value of the Harrier in air defence because of its unique agility and ability to stop in mid-air was realized later - and was not a built in design requirement. It is easy for us to forget that the Harrier was designed as an aircraft that had a T/W ratio of more than 1 - which is essential for vertical take off. That means that it could, from the outset, do rolling takeoffs when loaded with something more than its engine thrust would allow for vertical takeoff. That is why it was always designated as V/STOL. It also carried a load of plain water to be injected into the exhaust for vertical landing so that the tarmac/deck would not get too hot. In other words built in payload redundancy was a design requirement for the Harrier. Most pre-1980s aircraft designated as supersonic interceptors could make T/W ratios of nearly 1 or greater than 1 only when lightly loaded and after burning up some fuel. In any case a T/W ratio of >1 during takeoff (which burns a lot of fuel) is pointless except for VTOLs and rockets

The LCA was envisaged as a multirole fighter from day 1 unlike the MiG 21. It had dedicated hardpoints for mud moving munitions and this entire discussion is about one-single outboard hardpoint per wing whose design specs turned out to not be future proof. This is IMO the highest degree of nitpicking. The upgrades that the MiG 21 and Jaguars later received made them what they are and not original design specs

The image below was taken by me in 2003 - but this was pretty much the advertised loadout and you can see that it has dumb bombs, LGBs, BVRAAMs and rocket pods. And the R-60. And we seem to be haggling a lot about one pylon saying that the designers were short sighted. I disagree

Marten · Post by **Marten** » 07 Apr 2017 18:38

JayS, SPJ is about 100kgs. RWR has also caused some pain due to lack of space. As an innovative bunch, we would have found more uses for empty pylons until the design revision. We've lost substantial time due to the lack of flexibility. Unless ASQR demanded seven pylons, why let it be a show stopper?

JayS · Post by **JayS** » 07 Apr 2017 18:57

Marten wrote:JayS, SPJ is about 100kgs. RWR has also caused some pain due to lack of space. As an innovative bunch, we would have found more uses for empty pylons until the design revision. We've lost substantial time due to the lack of flexibility. Unless ASQR demanded seven pylons, why let it be a show stopper?

If ASQR did not ask for 7 pylons then yes, I agree.

And I already mentioned, assuming they could not take anything more than 45kg R60.

BTW there isn't much difference between 100kg SPJ and 110kg R73.

Marten · Post by **Marten** » 07 Apr 2017 19:08

The smaller one 8122 weighs lesser iirc, but I may be wrong.
The point was that they could find other uses and found a shorter path to certification, user acceptance. A multi ejector rack would be useful across platforms and wing redesign or structural strengthening could thereby be left for later. I would love to learn the tradeoffs discussed before they chose the path they did.

negi · Post by **negi** » 07 Apr 2017 19:20

Karan M wrote:Negi, that future proof Arjun is too heavy for the IA. Perhaps we need to put a cannon in a pod for the LCA and sell it to IA as lighter than T-72 MBT and sell the Arjun to AF as Brahmos capable heavier than MMRCA class. See, problem solved!!

Karan well Arjun being heavy is a different argument does IA like it or not is a 'subjective' matter but the point I was trying to make in this context was Arjun surpassed it's competition in trials and that has been quantified and established . You know this probably the best on this board but Arjun is a nice case study for all those in MIL product development as to why starting with a larger platform works better than going with 'compact' approach when the mission scope, requirements are fluid and development cycles are long. If Arjun would have started off with T-72 replacement objective and stuck to small compact tank theme in letter it would not have been better protected than say the T-90 today nor would it be able to lend itself to quick upgrades; remember Arjun outran and outgunned the latest offering from Ru in the same segment , that is no mean feat . My intention here is not to take sides but to merely point to the fundamental fact that Tejas has a uphill task when it comes to any requirement around re-equipping or increase in loadout because of it's compact size nothing more nothing less.

JayS · Post by **JayS** » 07 Apr 2017 19:38

srai wrote:

Looking at this image, if the two outboard pylons were unusable for CCMs (and thereby any other weapon), LCA would need too many combinations of dual racks to be able to keep the same weapons loads e.g. 800ltr tank + CCM, 1000lb LGB + CCM, BVR + CCM, AShM + CCM and so on.

One option was, (which I have advocated previously and I rather like it) is to induct MK1 in A2A + limited A2G role and quickly move on to MK2 with full multirole capabilities. I believe it would have been possible to induct such limited capability MK1 by 2010 time frame.