ADA Tejas (LCA) News and Discussions

[Kunal Biswas]

Poll added..

 

[ersakthivel]

i would like to thank (a little belatedly) Admin for the previous thread ( now appropriately closed and merged with this one ) for letting us continue to have a great discussion on the LCA-Kaveri ... by keeping the discussion on-track, at a good professional and technical level avoiding flaming and all that ....many thanks to Mr Kunal and our colleagues in admin ...ive learned many an interesting fact and view the LCA project and all the dedicated officers and technologists with a lot more renewed respect thanks to all your inputs ....will continue to read this lively discussion, keep it up !

A lot of people associated with the project have stayed loyal despite all the unfounded crititcism and step motherly attitude meted out to them.

Some very interesting reports about real people and the troubling times in TEJA project can be read in the following links.

http://tarmak007.blogspot.in/2011/01/world-beaters-fly-by-wire-fcs-will-take.html
http://tarmak007.blogspot.in/2011/01/world-beaters-fly-by-wire-fcs-will-take.html
http://tarmak007.blogspot.in/2011/01/world-beaters-fcs-story-from-ade-part-1.html

In contrast you can compare the tons of mud thrown on tejas in a filght global article-2009 ,
which I have posted in thepost no- 3362,3365 ,page no-225 in tejas -III thread,in the following link,
http://defenceforumindia.com/forum/indian-air-force/18521-ada-tejas-lca-iii-225.html
Foreign publications willfully indulge in this type of slander to demean tejas with no truth.

 

[ersakthivel]

In the above article the author keeps repeating that the mig-21 which has a laughable 30 km radar tracking range is
superior to tejas which has a radar tracking and detection range of 150 km.
Incidentally the tejas can carry more than twice the load of mig-21 .

http://defenceforumindia.com/forum/indian-air-force/18521-ada-tejas-lca-iii-154.html


nitesh's post no-2301 has the intervie of the IIT ALUMINI KOTA HARINARAYANA who designed the aircraft.
a few excerpts

We also wanted to change the aerodynamics. We developed a concept called Vortex plate. We didn't know at that time that we were the first in the world to develop something like this. NASA developed a similar concept only six years later.


The greatest contribution of the LCA project is that in a country like India where people say that two people cannot work together, we were 5000 engineers working with 300 industries, about 40 laboratories and 20 academic institutions. And we worked together successfully. And at a time when there were US sanctions and they were not willing to cooperate with us, this team made this aircraft. That was a great experience. Tough but great.


Today if you see engineering service industry in India, I think a large number of people manning the industry have worked on the LCA project. Because they worked on LCA, they got good work afterwards.

I think the biggest thing is that we created the ecosystem for aviation in India. Earlier there was no ecosystem for aviation in India. There was HAL and nobody else. Now it is HAL, 500 industries, 40-50 laboratories, 20 academic institutions and it is a big network. It is no longer one or two people working or one DRDO lab working or NAL working

. It is a network. I thought this ecosystem that we have created through LCA is a great thing and it has given extra-ordinary confidence to the people who have worked on the project and the people who felt that this cannot be done but now they feel that if they could do LCA, they can do many other things.

We tested on a modified F16 aircraft in USA. One of the comments of the test pilot from the Pentagon was that the F16 flies better with LCA control laws. Even the aerodynamics of the aircraft was excellent. It gave a lot of confidence to our pilot. I never wanted to side step any testing. I felt that you must test until you give confidence to the airworthiness team and to the pilots. So the whole testing process went on for a year.

But we had a wonderful Defence Minister in George Fernandes. He is a great Swadeshi man. One day we were working very late at night around 11 'o clock, testing the ground run of the aircraft. And suddenly some five-six cars came. It was the Defence Minister. He said, 'As I was landing, I saw some activity going on. And I knew it must be your group.' Such a gesture on his part energized the team, the designers, the people who had built the aircraft and the people who were testing it. Dr.Kalam was our boss for a long time. He was also an extra-ordinary person.

Pity the man is no more to see the induction of LCA in service.

Fortunately, I have had very good bosses. All of my bosses have supported us fully. We went through extra-ordinary problems. There used to be negative publicity about the project every alternate day. They used to say that we had crossed the time limits and the budget. It was tough but then our focus was not on those reports but on how to make it work. Fortunately, the team believed in themselves. Even if others didn't believe, it didn't matter. I think our big achievement was in making the team believe in themselves.

http://tarmak007.blogspot.in/2012/06/claw-ing-ahead-tejas-clan-who-overcame.html
This is another link for the claw team's work.

 

[Kunal Biswas]

Better pic..

 

[average american]

Better pic..

When you think about it, just imagine, just one little mistake in design, one little mistake in the manfacture of one part may mean the plane crashs.l

 

[roma]

When you think about it, just imagine, just one little mistake in design, one little mistake in the manfacture of one part may mean the plane crashs.l

so india has been able to get to that level of mastery - what needs to be done next is to apply the same management and technological capability to other aspects of life in india

 

[SATISH]

When you think about it, just imagine, just one little mistake in design, one little mistake in the manfacture of one part may mean the plane crashs.l

Well American aircrafts are far more complex than this.

 

[Abhi9]

I was reading some interesting article on wing design and particularly delta wings. What ERSakthivel is saying is right. Tejas wingloading is lower than mirage-2000, which will give it a far better high altitude performance, but at the same time delta wing act as enormous air brake during turn operation so at low altitudes where the air is thick and heavy the Tejas will bleed energy during turns and pulling Gs but this limitation can be avoided by a good pilot taking the engagement to high altitudes and operate in LOOK DOWN and SHOOT DOWN area.

Also with high thrust engines, the turn rate can be maintained even though the delta bleeds energy half way into turn but with higher thrust can result in increased angular momentum, thus increased velocity coming out of the turn.

 

[ersakthivel]

I was reading some interesting article on wing design and particularly delta wings. What ERSakthivel is saying is right. Tejas wingloading is lower than mirage-2000, which will give it a far better high altitude performance, but at the same time delta wing act as enormous air brake during turn operation so at low altitudes where the air is thick and heavy the Tejas will bleed energy during turns and pulling Gs but this limitation can be avoided by a good pilot taking the engagement to high altitudes and operate in LOOK DOWN and SHOOT DOWN area.

Also with high thrust engines, the turn rate can be maintained even though the delta bleeds energy half way into turn but with higher thrust can result in increased angular momentum, thus increased velocity coming out of the turn.

What you are saying is correct. All fighters after F-16 are low wing loading fighters only.The reason is,
eventhough low wing loading fighters bleed off energy at tight sustained turn rates at lower altitudes, compared to high wing loading fighters,
they have much higher instantaneous turn rates than high wing loading fighters.

SO even in a tight sustained turn rate engagements at lower altitudes, the low wing loading fighter can use this higher instantaneous turn rates (typical of hypothetical mirage -2000 vs F-16 discussions in the net)to fire high OFF-BORE sight missiles at a tighter turning high wing loading fighter.The high wing loading fighter can never out turn a missile.

Also if you want to deploy counter measures and evade this low wing loading is also very important for this purpose, A few high G instantaneous turns are much more effective than prolonged higher sustained turns,



The low wing loading fighter can easily take off with much heavier weapon loads from high altitude airfields like LEh.A very vital need for TEJAS,even with 70 kn under powered GE-404 engine tejas was able to do it, that to within 85 percent of the engine capacity.

That's the reason why grippen,eurofighter,rafale,F-22,PAKFA all have much lower wing loading compared to F-16.

Also if you want to utilize long range BVRs of today ,you must shoot them from high altitudes only, to get their max range of 120 km or so.
The high wing loading fighters held their own in the pre awcas era of tree top flying to avoid ground radar and dumb bombing at lower altitude(jaguar is a prime exmple of this)
But with the advent of awcas this low level flying won't guarentee radar evasion,
and with proliferation of shoulder fired heat seeking misiles ,your reaction time to deploy coutner measures will be very low,
and with long range stand off weapons fighters can fire on ground tatget from long distance at high altitudes using long range stand off weapons.
For example a rafale hit a libiyan tank from many kilometers away with stand off long range guided munitions,according to news source.

Also sustained turn rate is a combined function of
1.Thrust to weight ratio of the fighter,
2.wing loading,
3.Angle of Attack.
Usually deltas have higher angle of attack and lower wing loading compared to high wing loading fighters like F-16.
Also tejas will have a much lower wing loading and more TWR than mirages, so even it's sustained turn performance will be comparable to modern high wing loading fighters.

Because sustained turning at knife's edge position is nothing but climbing in a horizontal circular path.
So low wing loading and higher thrust to weight ratio will compensate the bleeding off energy to a certain extent.

 

[Abhi9]

Deltas have a additional advantage that they can perform high angle of attack approach at lower speeds without stalling than wings with high loading with because of higher lift.

 

[Kunal Biswas]

Some important notes on NLCA Project..

 

[anoop_mig25]

^^^^^ thanks for pics sir

 

[p2prada]

I was reading some interesting article on wing design and particularly delta wings. What ERSakthivel is saying is right. Tejas wingloading is lower than mirage-2000, which will give it a far better high altitude performance, but at the same time delta wing act as enormous air brake during turn operation so at low altitudes where the air is thick and heavy the Tejas will bleed energy during turns and pulling Gs but this limitation can be avoided by a good pilot taking the engagement to high altitudes and operate in LOOK DOWN and SHOOT DOWN area.

One of the rules of dog fighting, you don't try to climb. You try to drop down to maintain energy.

Also with high thrust engines, the turn rate can be maintained even though the delta bleeds energy half way into turn but with higher thrust can result in increased angular momentum, thus increased velocity coming out of the turn.

Mirage-2000s use ABs to maintain turn rates against better turning opponents like F-16s.

That's why Mirage-2000 pilots openly say that if they don't get the advantage within the first minute, they pretty much lost the fight. They have neither the power, nor the fuel to stay in the game.

 

[Abhi9]

One of the rules of dog fighting, you don't try to climb. You try to drop down to maintain energy.



Mirage-2000s use ABs to maintain turn rates against better turning opponents like F-16s.

That's why Mirage-2000 pilots openly say that if they don't get the advantage within the first minute, they pretty much lost the fight. They have neither the power, nor the fuel to stay in the game.

I was not talking about climbing, i was insinuating that the engagement is taking at high altitudes. yes you are right that climbing would be a waste of energy. Also can you enlighten me that at generally what altitude to CAP is undertaken.

 

[Godless-Kafir]

Deltas have a additional advantage that they can perform high angle of attack approach at lower speeds without stalling than wings with high loading with because of higher lift.

large Delta wings also cause more drag in high AoA and bleed energy and momentum fast.

 

[ersakthivel]

One of the rules of dog fighting, you don't try to climb. You try to drop down to maintain energy.

if one guy starts to climb ,the other has to follow him to engage in dog fight.
Also deltas swooping down on high wingloading fighters from altitude have more energy.

Mirage-2000s use ABs to maintain turn rates against better turning opponents like F-16s.

That's why Mirage-2000 pilots openly say that if they don't get the advantage within the first minute, they pretty much lost the fight. They have neither the power, nor the fuel to stay in the game.

The F-16 hardly ever escapes from a high off bore WVR missile shots,so a skilled mirage pilot will finish the fight then and there.
Also mirage has a twr less than 1.Lca has 1.07 for mk-I and more than 1.2 for mk-2.
So deltas with higher TWR like tejas won't be found wanting in energy after the first pass is missed.

That's why every one is building low wing loading deltas these days like grippen,F-22,Rafale,PAKFA,eurofighter.
No one has the higher 400 plus kg/sq.met. wing loading of F-16.

 

[ersakthivel]

large Delta wings also cause more drag in high AoA and bleed energy and momentum fast.

Then why every fighter manufacturer like LM , Boeing , Sukhoi , Dassault ,EADS ,chengdu,SAAB are building low wing loading fighters? 4th gen or 5th gen?
Why are they not building high wing loading energy retaining fighters like F-16 ,which has a wing loading of 400 plus kg/sq.met.?

 

[p2prada]

I was not talking about climbing, i was insinuating that the engagement is taking at high altitudes. yes you are right that climbing would be a waste of energy. Also can you enlighten me that at generally what altitude to CAP is undertaken.

Dog fights that happen at high altitudes come down to low altitudes very quickly, unless the engagement ends within the first minute.

There is no hard and fast rule for CAP altitude. But you can say, 8 to 12 Km.

 

[p2prada]

Fighter design has always been a compromise between high wing loading advantages in lower altitudes and low wing loading advantages in higher altitudes.

A low wing loading design for LCA is only suited for interceptor roles for delta wing designs.

Apart from that Su-35 has higher wing loading at ~500Kg/m2 than both F-35 and F-16. It is considered to be the second best operational air superiority fighter today. It is also 400+ Kg/m2 design with 50% fuel and weapons. The additional lifting surfaces are what provides greater lift as compared to simpler designs like LCA and Mirage-2000. Even F-16 has a more complex lifting design.

FBW beats the low and high wing loading advantages/disadvantages. That's the reason why F-16 has superior maneuverability in turns and rolls as compared to a LCA class low wing loading on Mirage-III.

Anyway, low/high wing loading depends on your perspective. If you take LCA as a benchmark then all modern aircraft have very high wingloading, between 350 and 500Kg/m2. If you don't consider LCA as a benchmark then all aircraft have very similar wing loading figures between 350 and 500Kg/m2 at decent loads.

At full internal fuel and 2 tons payload,

F-35A is at 559 Kg/m2.
SH is at 501 Kg/m2.
F-16 B52 is at 473 Kg/m2.
F-15E is at 394 Kg/m2.

F-22 is at 384 Kg/m2.
Su-35 is at 514 Kg/m2.
PAKFA estimated at 400+ Kg/m2.
Rafale is at 350 Kg/m2.
EF-2000 is at 348 Kg/m2.

LCA is at 286 Kg/m2.

So, compared to LCA, all other aircraft have extremely high wing loading. OTOH, you can say LCA has far too less wing loading which will actually affect a lot of other aspects when it comes to flying as compared to the more balanced approach taken by other designers.

 

[ersakthivel]

Fighter design has always been a compromise between high wing loading advantages in lower altitudes and low wing loading advantages in higher altitudes.

A low wing loading design for LCA is only suited for interceptor roles for delta wing designs.

Apart from that Su-35 has higher wing loading at ~500Kg/m2 than both F-35 and F-16. It is considered to be the second best operational air superiority fighter today. It is also 400+ Kg/m2 design with 50% fuel and weapons. The additional lifting surfaces are what provides greater lift as compared to simpler designs like LCA and Mirage-2000. Even F-16 has a more complex lifting design.

FBW beats the low and high wing loading advantages/disadvantages. That's the reason why F-16 has superior maneuverability in turns and rolls as compared to a LCA class low wing loading on Mirage-III.

Anyway, low/high wing loading depends on your perspective. If you take LCA as a benchmark then all modern aircraft have very high wingloading, between 350 and 500Kg/m2. If you don't consider LCA as a benchmark then all aircraft have very similar wing loading figures between 350 and 500Kg/m2 at decent loads.

At full internal fuel and 2 tons payload,

F-35A is at 559 Kg/m2.
SH is at 501 Kg/m2.
F-16 B52 is at 473 Kg/m2.
F-15E is at 394 Kg/m2.

F-22 is at 384 Kg/m2.
Su-35 is at 514 Kg/m2.
PAKFA estimated at 400+ Kg/m2.
Rafale is at 350 Kg/m2.
EF-2000 is at 348 Kg/m2.

LCA is at 286 Kg/m2.

So, compared to LCA, all other aircraft have extremely high wing loading. OTOH, you can say LCA has far too less wing loading which will actually affect a lot of other aspects when it comes to flying as compared to the more balanced approach taken by other designers.

.Su-35 has thrust vectoring, which improves it's ITR and vertical handlling,without thrust vectoring a low wing loading is essential for good performance at high altitudes and for a good instantaneous rate.If



where is grippen's low wing loading in this list,which easily beats the F-16 by a mile.It is 283 kilograms per meter square only 66 % of F16s wing loading, which is 431 kilogram per meter square ...

FBW has no relation to wing loading.
FBW can only exploit the fighter's design capabilities,it cannot exceed it.

And there is no source for the claim of F-16's higher roll rate.Lower the wingloading lower th thrust needed to lift and fly with higher BVR and ground weapon loads.That's what wing loading is.Nothing else.

wing loading figures between 350 and 500Kg/m2 at decent loads is not a narrow band range.

It is a very wide range

A proper perspective is,

So a rafale and eurofighter(both without thrust vectoring.So they have to rely on wing loading for vertical agility) with 350 for wingloading is close to 286 for tejas.

A F-22 with 384 also has thrust vectoring( in vertical plane only, as it has 2D thrust vectoring opposed to 3D in sukhoi) to improve it's vertical handling .Otherwise what is the use of thrust vectoring?

A F-16 with 484 is close to SU-35(which has thrust vectoring to improve vertical handling as well).

Su-35 has thrust vectoring in 3D, which improves it's ITR and vertical handlling,without thrust vectoring a low wing loading is essential for good performance at high altitudes and for a good instantaneous rate.

If Thrust vectoring is added in latter stage ,it will massively improve tejas mk-II's handling as well.

There is no rule that thrust vectoring is not needed for small fighters.The russians who first introduced thrust vectoring in Sukhoi introduced it in in twin engined su-30 MkI.That's all.So that doesn't preclude this feature from added to a single engined fighter.

The all moving all protruding control surfaces of SU-35 gives it a higher RCS as well.