LCA: News & Discussions: 15 August 2017

shiv · Post by **shiv** » 13 Dec 2017 10:39

Indranil wrote:It is exactly that. It is a supersonic dash from TO to intercept within 10 minutes, subsonic thereafter.

I expect LCA to be able to this with 4 AAMs each though.

If you know, and if it is not a state secret. What is Tejas climb rate?

Indranil · Post by **Indranil** » 13 Dec 2017 10:42

Viv, your inlets have to be of variable geometry to reach 2M. But, you need sufficient oomph too.

The Mig-21 is basically cylinder around an engine. It's shape and TWR will allow more bulges at the center. This isn't the case with LCA, Gripen, Jf-17 etc.

shiv · Post by **shiv** » 13 Dec 2017 10:49

Mach 2 is cold war heritage. They had to catch and hit high flying bombers.

Aditya_V · Post by **Aditya_V** » 13 Dec 2017 11:29

That too with K-13(AA-2) type missiles

Cain Marko · Post by **Cain Marko** » 13 Dec 2017 11:46

shiv wrote:
Cain Marko wrote:. btw why would plane be restricted to only 2 AAMs? Wouldnt this be a function of its thrust ? I seem to recall seeing Rafale and M2k pics with supersonnic efts and bristling with AAMs...
Those Rafale pics show 4 BVR and 2 WVR - and vulgar looking aesthetics killing drop tankis but those planes are on AWACS controlled timepass CAP mission. Not even one AAM has ever been actually phyrred.

What I am talking about is actual conflict like scenario where Tejas is required to close in on a target that has just entered Indian airspace and intercept ASAP. In the Indian situation this has often meant visual identification. Hence WVR. And for acceleration and high climb rate - just 2 AAMs. If two Tejas take off - that gives 4 AAMs and the possibility of nailing the target from two different directions.

My guesstimate is a target 100-150 km away requiring contact within minutes

Could the Tejas manage a supersonic dash of 150km loaded with aams on internal fuel alone and then have enough fuel to engage in a showdown and then come back? I'm not sure.

Also, what if the iaf intends to maintain a no fly zone over some airspace? Won't it need fighters doing caps to reach hot spots in a jiffy?

Or what if an Awacs escort needs to intercept enemies at long ranges? Time would be of the greatest essence and supersonic efts would be rather useful.

srai · Post by **srai** » 13 Dec 2017 11:55

^^^
Already answered by the LCA supersonic tank study presentation. A large part of air superiority missions would be spent on patrolling a specified area. That is where supersonic tanks have their usefulness. Get there quickly and spend x amount of time there. If during that time, an enemy contact is made then drop the tank and engage.

viewtopic.php?f=3&t=7368&start=2240#p2237147

Specific Air-superiority missions need the use of a supersonic fuel tank to reach a far-off location as fast as possible and patrol the target zone.

This configuration is seen quite a few times on the IAF Mirage-2000 with its centerline supersonic tanks.

Another more clearer image (not IAF though):

Indranil · Post by **Indranil** » 13 Dec 2017 12:31

shiv wrote:
Indranil wrote:It is exactly that. It is a supersonic dash from TO to intercept within 10 minutes, subsonic thereafter.

I expect LCA to be able to this with 4 AAMs each though.
If you know, and if it is not a state secret. What is Tejas climb rate?

When you talk to scientists, they would say under what operation configurations?

They don't quote or probably even know the theoretical max which one does starting at almost top speed and bingo fuel.

ASR requirements AFAIK was 200 mtrs/sec at take off in Operational Clean Configuration (2 AAMs only). LCA manages that comfortably. You must have read about our Mig-29s escorting our Mirages during Kargil during bomb runs. Here's an LCA trainer taking off with two 1000 lb bombs, 2 AAMs and 2 1200 ltr fuel tanks during summer trials, at Leh! If it were an SP aircraft without the instrumentation, you could have easily added the LGP guidance kits and LDP. Do you have any doubts that it will lack in operational climb rate?

Kersi · Post by **Kersi** » 13 Dec 2017 12:55

shiv wrote:
JTull wrote:
Also, why should a drop tank suitable for another aircraft, say Mig-21, will be suitable for LCA? What's the harm in developing customised drop tanks that are more aerodynamic and suitable to the mission profiles of LCA? Who's is to say that a 'supersonic' drop tank won't help in sub-Mach/transonic flight.
Sir you are asking me a question in response to my questions. But do you have an answer. This is a non answer

Drop tanks are specific to the aircraft. More so for the supersonic drop tanks

nam · Post by **nam** » 13 Dec 2017 22:06

Something i just noticed. Mig-21 can carry drop tanks on it's outer plyons!

I wonder if such a requirement was ever considered for LCA. Ofcourse the size of the wings are different, may be a factor.

ramana · Post by **ramana** » 14 Dec 2017 00:49

nam wrote:Something i just noticed. Mig-21 can carry drop tanks on it's outer plyons!

I wonder if such a requirement was ever considered for LCA. Ofcourse the size of the wings are different, may be a factor.

This will start another while article about how Mig 21 is superior as it can carry drop tanks on out pylons.

ramana · Post by **ramana** » 14 Dec 2017 00:50

Also all this discussion on supersonic drop tanks will generate an article why cant LCA use existing supersonic drop tanks?

Sometime I wish it was all under burkha. But we know where that led.

dkhare · Post by **dkhare** » 14 Dec 2017 02:52

In case of the MiG 21, it was initially designed as a cheap, short range, day time, supersonic interceptor with no gun and with just 1 pylon per wing for precisely the 10 minute supersonic dash to intercept incoming nuclear bombers. They added an extra pylon and plumbing for tanks when users wanted more payload and endurance. When the main landing gears are deployed, they may be too close to the inboard pylons. This prevents any stores that are above a certain size/diameter to be placed on the inboard pylons. The outer pylons are the only remaining option for wing based external fuel tanks. Iterative development but still constrained by existing design decisions.

The ADA LCA design team anticipated some of this and designed the inboard, mid-board, and center line pylons to carry external fuel tanks, affording mission flexibility.

ramana · Post by **ramana** » 14 Dec 2017 03:12

Wow. Very good explanation.

Indranil · Post by **Indranil** » 14 Dec 2017 05:03

Nam,
There are advantages and disadvantages of wingtip tanks. However, on wings with a significant taper designers typically try to decrease the loadout along the span. Unless it is not possible, as in the case of the Mig-21 as explained wonderfully by dkhare sir ahead of me.

Ramana sir,
As others have said, supersonic tanks are specific to an aircraft. Even one designed for Mk1 might need refinements for Mk2.

Indranil · Post by **Indranil** » 14 Dec 2017 05:08

Indranil wrote:
shiv wrote:
If you know, and if it is not a state secret. What is Tejas climb rate?
When you talk to scientists, they would say under what operation configurations? They don't quote or probably even know the theoretical max which one does starting at almost top speed and bingo fuel.

ASR requirements AFAIK was 200 mtrs/sec at take off in Operational Clean Configuration (2 AAMs only). LCA manages that comfortably. You must have read about our Mig-29s escorting our Mirages during Kargil during bomb runs. Here's an LCA trainer taking off with two 1000 lb bombs, 2 AAMs and 2 1200 ltr fuel tanks during summer trials, at Leh! If it were an SP aircraft without the instrumentation, you could have easily added the LGP guidance kits and LDP. Do you have any doubts that it will lack in operational climb rate?

I think I am revisiting this again. If an aircraft can take off at Leh in summer with near 3 tons of payload, how come its maximum payload capacity is 3.8 to 4 tons only?

ADA requires a marketing department. Which identifies some test conditions for brochure numbers only!

ks_sachin · Post by **ks_sachin** » 14 Dec 2017 05:12

Indranil wrote:Nam,
There are advantages and disadvantages of wingtip tanks. However, on wings with a significant taper designers typically try to decrease the loadout along the span. Unless it is not possible, as in the case of the Mig-21 as explained wonderfully by dkhare sir ahead of me.

Ramana sir,
As others have said, supersonic tanks are specific to an aircraft. Even one designed for Mk1 might need refinements for Mk2.

Indranil, Ramana, deejay et all thanks all for some wonderful contributions. Also some very intelligent questions. This drop tank discussion is what makes BR good.
For one steeped in the infantry ethos it is good to get insight into the other aspects.

shiv · Post by **shiv** » 14 Dec 2017 05:39

nam wrote:Something i just noticed. Mig-21 can carry drop tanks on it's outer plyons!

I wonder if such a requirement was ever considered for LCA. Ofcourse the size of the wings are different, may be a factor.

Saar MiG 21 used to have only 2 wing pylons when we bought it and used it as frontline fighter for phull 10 years. Later iterations incorporated an extra 2. Give Tejas 10 years of service life no? Then ask.

Rakesh · Post by **Rakesh** » 14 Dec 2017 08:43

https://twitter.com/indiandefencera/sta ... 3509877760 --> SP-7 maiden flight took place today. Soon, after the customary initial flights, she will be handed over to the squadron.

Rakesh · Post by **Rakesh** » 14 Dec 2017 08:51

So much for mitigating risk

Why Building More Tejas Fighters Is A Superior Option For The Indian Air Force
http://www.delhidefencereview.com/2017/ ... air-force/

Indeed, India would be better off building variants from the Tejas family in numbers rather than pursuing the single-engine tender mentioned above which sees an ‘India specific’ Lockheed Martin F-16 variant in competition with the SAAB Gripen E/F.

Major sub-systems of both aircraft,the so called F-16 Block 70 and Gripen E, on offer as part of the single-engine tender, such as avionics, radar, engines, and electronic warfare (EW) systems will likely continue to be manufactured in their countries of origin even if a manufacturing line is opened in India. Transfer of any technology, as offered by SAAB and Lockheed Martin, is likely to remain limited to production (i.e. some know-how) alone and not offer any insight into design processes commonly referred to as know-why. This has been India’s experience with previous such offers leading to a situation whereby OEMs have milked the IAF for subsequent customizations and upgradation, such as the integration of new weapons and sensors. IAF upgrades to its Mig-21s, Mirage-2000 and Jaguar aircraft bear testimony to the peculiar behavior of various OEMs. Depending on OEMs for keeping imported or licensed produced aircraft viable clearly increases the life-cycle cost of the platform besides leading to major time penalties in terms of availability rates.

dkhare · Post by **dkhare** » 14 Dec 2017 09:17

Indranil wrote:Nam,
There are advantages and disadvantages of wingtip tanks. However, on wings with a significant taper designers typically try to decrease the loadout along the span. Unless it is not possible, as in the case of the Mig-21 as explained wonderfully by dkhare sir ahead of me.

Ramana sir,
As others have said, supersonic tanks are specific to an aircraft. Even one designed for Mk1 might need refinements for Mk2.

Please, no "sir" for me - just making humble contributions.

Thank you for posting important & pertinent information on the progress of our LCA Tejas. Its what makes so BR addictive - so many highly knowledgeable posters on this forum.

deejay · Post by **deejay** » 14 Dec 2017 11:47

Indranil wrote:
Indranil wrote: When you talk to scientists, they would say under what operation configurations? They don't quote or probably even know the theoretical max which one does starting at almost top speed and bingo fuel.

ASR requirements AFAIK was 200 mtrs/sec at take off in Operational Clean Configuration (2 AAMs only). LCA manages that comfortably. You must have read about our Mig-29s escorting our Mirages during Kargil during bomb runs. Here's an LCA trainer taking off with two 1000 lb bombs, 2 AAMs and 2 1200 ltr fuel tanks during summer trials, at Leh! If it were an SP aircraft without the instrumentation, you could have easily added the LGP guidance kits and LDP. Do you have any doubts that it will lack in operational climb rate?

...
I think I am revisiting this again. If an aircraft can take off at Leh in summer with near 3 tons of payload, how come its maximum payload capacity is 3.8 to 4 tons only?

ADA requires a marketing department. Which identifies some test conditions for brochure numbers only!

(Deleted image to occupy less space)

So you noticed. In all this constant attack on LCA, the ADA team has been very conservative with numbers to avoid controversy. I think they publish worst case numbers for LCA which are then pitted against best case numbers for Western ware!

Tejas deserves a marketing onslaught. Aggressive and polished. No inhibitions. The engineers have done the job and now its time to take it to market. Remember promise the moon and deliver Mars works if the customer knows it.

nachiket · Post by **nachiket** » 14 Dec 2017 12:56

Indranil wrote: I think I am revisiting this again. If an aircraft can take off at Leh in summer with near 3 tons of payload, how come its maximum payload capacity is 3.8 to 4 tons only?

ADA requires a marketing department. Which identifies some test conditions for brochure numbers only!

ADA needs to understand what is meant by brochure numbers first. I don't think they do.

nam · Post by **nam** » 14 Dec 2017 20:14

shiv wrote:
nam wrote:Something i just noticed. Mig-21 can carry drop tanks on it's outer plyons!

I wonder if such a requirement was ever considered for LCA. Ofcourse the size of the wings are different, may be a factor.
Saar MiG 21 used to have only 2 wing pylons when we bought it and used it as frontline fighter for phull 10 years. Later iterations incorporated an extra 2. Give Tejas 10 years of service life no? Then ask.

Sirji, just something that caught my eye. Not a wishlist.

Came to my mind, the issue of heavier CCM requiring strengthening of the wings. If Mig21 could carry drop tanks, I wondered if IAF had asked something similar in the initial requirements. It may have negated the need to strengthen the wings.

After all LCA was supposed to replace Mig21

srai · Post by **srai** » 14 Dec 2017 22:05

nam wrote:
shiv wrote: Saar MiG 21 used to have only 2 wing pylons when we bought it and used it as frontline fighter for phull 10 years. Later iterations incorporated an extra 2. Give Tejas 10 years of service life no? Then ask.
Sirji, just something that caught my eye. Not a wishlist.

Came to my mind, the issue of heavier CCM requiring strengthening of the wings. If Mig21 could carry drop tanks, I wondered if IAF had asked something similar in the initial requirements. It may have negated the need to strengthen the wings.

After all LCA was supposed to replace Mig21

Well, LCA can carry larger capacity drop tanks than the MiG-21 and at more hardpoints.

Mid-Wing -> 800ltr
Inner-Wing -> 800ltr or 1200ltr
Centerline -> 725ltr (and coming up 710ltr supersonic drop tank)
Inner-Wing -> 800ltr or 1200ltr
Mid-Wing -> 800ltr

Not enough?

Note: For MiG-21, you are looking at around 400ltr external drop tanks.

Indranil · Post by **Indranil** » 14 Dec 2017 22:42

Strength where you don't need it is excess weight.

Vivek K · Post by **Vivek K** » 14 Dec 2017 22:57

What is the question here - is Nam saying that LCA is not as good as Mig-21 because the wings are not strengthened to carry drop tanks on outer pylons? srai has provided a good response. As operational convention is finalized, the wings can be optimized downwards for weight savings. If this additional strength was not provided, the user would have complained that the LCA cannot even carry drop tanks.
So we criticize LCA if it has the capability and we also criticize it if does not - damned if you do and damned if you don't!

ashishvikas · Post by **ashishvikas** » 14 Dec 2017 23:44

srai wrote:
nam wrote:
Sirji, just something that caught my eye. Not a wishlist.

Came to my mind, the issue of heavier CCM requiring strengthening of the wings. If Mig21 could carry drop tanks, I wondered if IAF had asked something similar in the initial requirements. It may have negated the need to strengthen the wings.

After all LCA was supposed to replace Mig21
Well, LCA can carry larger capacity drop tanks than the MiG-21 and at more hardpoints.

Mid-Wing -> 800ltr

Inner-Wing -> 800ltr or 1200ltr

Centerline -> 725ltr (and coming up 710ltr supersonic drop tank)

Inner-Wing -> 800ltr or 1200ltr

Mid-Wing -> 800ltr
Not enough?

Note: For MiG-21, you are looking at around 400ltr external drop tanks.

Sir, has Mid-Wing 800ltr drop tank been tested already ? I tried to find any pictures of it without any success.

nachiket · Post by **nachiket** » 14 Dec 2017 23:56

Plumbing of the mid-wing pylon was completed only recently per Indranil. So there may not be any photos.

Khalsa · Post by **Khalsa** » 15 Dec 2017 01:43

Rakesh wrote:https://twitter.com/indiandefencera/sta ... 3509877760 --> SP-7 maiden flight took place today. Soon, after the customary initial flights, she will be handed over to the squadron.

Heartening to know.
Wish the IAF would go for understrength squadrons seeding the future instead of the 20 that I keep on hearing again.

Rakesh, would you know what does the IAF playbook say.
Is 16 the magic number for a squadron ?
does that include the trainers or are they surplus

ramana · Post by **ramana** » 15 Dec 2017 02:22

I would like to know about SP-5 as that means the half assy line is operationalized.

Rakesh · Post by **Rakesh** » 15 Dec 2017 03:12

ramana wrote:I would like to know about SO-5 as that means the half assy line is operationalized.

I am assuming you mean SP-5? I would like to know as well. We need someone to compile & maintain a running list of SP aircraft that join No 45 Sqn and future squadrons. Good to know how the numbers are stacking up against production claims.

Rakesh · Post by **Rakesh** » 15 Dec 2017 03:14

Khalsa wrote:
Rakesh wrote:https://twitter.com/indiandefencera/sta ... 3509877760 --> SP-7 maiden flight took place today. Soon, after the customary initial flights, she will be handed over to the squadron.
Heartening to know.
Wish the IAF would go for understrength squadrons seeding the future instead of the 20 that I keep on hearing again.

Rakesh, would you know what does the IAF playbook say.
Is 16 the magic number for a squadron ?
does that include the trainers or are they surplus

18 is the standard number. I have seen that number vary depending on aircraft. But 18 is usually the number the IAF aims for.

Back in the early 1990s, there was a planned production run of 220 Tejas aircraft. This is before Mk1, Mk1A and Mk2 and all that.

200 Single Seaters + 20 Trainers. 10 Squadrons with 20 single seater aircraft and 2 trainers.

Obviously, those numbers have changed now. Right now, it is 40 Mk1s (20 in IOC and 20 in FOC) and then 83 Mk1As.

Kartik · Post by **Kartik** » 15 Dec 2017 03:21

A poster on another forum mentioned that SP-8 too is likely to have its first flight by the end of December. Once handed over to No.45 squadron, they'll be at half strength.

Khalsa, the IAF has identified No.18 Squadron 'Flying Bullets', Flying Officer Nirmaljit Singh Sekhon's squadron, as the next Tejas squadron. An honor. Activities to start the squadron formation tasks should start next year, since No.45 squadron would have received all its jets by March 2019.

Indranil · Post by **Indranil** » 15 Dec 2017 04:30

Ramana sir and Rakesh,
SP-5 should join before Christmas.

By April of next year, IAF should have 10 LCAs.

Cybaru · Post by **Cybaru** » 15 Dec 2017 04:32

Ahead of schedule indranil?

Indranil · Post by **Indranil** » 15 Dec 2017 04:45

On schedule. By the way, the SPJ pod design has been completed by DARE. It has given put out a tender to manufacture 4 of these in 8 months from placement of order.

ramana · Post by **ramana** » 15 Dec 2017 05:07

Great will eagerly await the completion of the milestone.

Good news about the SPJ pod. That means the electronics for it is also ready.
Lot of riveted construction and curved plates. The two dished ends are RF transparent? I.E fiberglass?

Indranil · Post by **Indranil** » 15 Dec 2017 05:29

ramana wrote:Great will eagerly await the completion of the milestone.

Good news about the SPJ pod. That means the electronics for it is also ready.
Lot of riveted construction and curved plates. The two dished ends are RF transparent? I.E fiberglass?

RF Transparent and to be provided by DARE.

nachiket · Post by **nachiket** » 15 Dec 2017 05:43

Indranil wrote:On schedule. By the way, the SPJ pod design has been completed by DARE. It has given put out a tender to manufacture 4 of these in 8 months from placement of order.

Good news. Can this pod be carried in place of the LDP or only on a regular pylon?

Vivek K · Post by **Vivek K** » 15 Dec 2017 05:50

Indranil wrote:Ramana sir and Rakesh,
SP-5 should join before Christmas.

By April of next year, IAF should have 10 LCAs.

Admiral - now can we have that mithai?