LCA News and Discussions

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D Roy
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Re: LCA News and Discussions

Postby D Roy » 24 Oct 2010 22:15

ultimately almost every damn modern day fighter is a delta of some sort.

and yes the pure delta fell out of favour because of its tendency to induce drag flying low and the restrictive AoA, but has made a comeback in combination with canards, hain?

and in the case of the Tejas it's delta is sweep varied anyway.

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Re: LCA News and Discussions

Postby shiv » 24 Oct 2010 22:17

Rahul M wrote:>> And even the French stepped out of deltas after the Mirage 2000.

not so. rafale. in fact worldwide there is a clear move towards deltas, EF, rafale, gripen, J-10.


No I meant to type tailless/canard less. And that is why I am asking this question for the third time on this thread. The cranked double delta with its control surfaces apparently acts like a canard. Is this true or not? Who will say?

What is the use of a horizontal tailplane in an aircraft? What is the use of a canard? Why can deltas manage without a tail? I can answer all these myself using my uncle Google. But what thoughts go through a designers mind when he chooses or discards any of these features? Who will tell? What thoughts went through the mind/s of the designers of Tejas when they set their minds on the tailless cranked double delta design?

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Re: LCA News and Discussions

Postby Gaur » 24 Oct 2010 22:31

shiv wrote:
Gaur wrote:
However, you seem to have deviated from the point. Your said understanding of the author's belief was that the LCA designers just gulped the lie of the world regarding FBW. My post was regarding why I think that is highly unlikely.


So you are telling me that you disagree with my understanding of what Das writes? I am fine with that. But what do you think Das means? What I think is irrelevant and what you think of what I think is even less relevant.


To be perfectly honest, that paragraph was just a polite way of requesting you not to put words in my mouth. :P
You post deviated from our discussion and seemed to indicate (at least to me) that I was discussing whether Tejas could fly without FBW or not (which IMO is a moot discussion) and also whether India should have chosen FBW or not (a debatable discussion which has valid points on both sides).

It is totally possible that either this was unintentional on your part. It is even more possible that it was just my imagination. If it was either of the two case, let me apologize.

Now, to your question regarding my understanding of what Proff Das means. I think he means exactly what you say he means. So, again, I do not think you misinterpreted his words. I was just pointing out the reasons for my disagreement with a particular part of his article.

<snip>
Given that the design was frozen as a tailless cranked double delta the designers and developers have done well and their experience should be carried forward. But if mistakes were made in the 1980s that led to delays - let us know how those mistakes were made. Or let is know that no mistakes were made. Let us know if the ASR demanded specs that inevitably pointed to a delta design. It is a typically Indian phenomenon to not rake up old issues because some respected elder may be shamed. Is that what is happening here? We need not shame or curse anyone but I would like to know how and why why a "cranked double delta design was conceived?

Your opinion that the designers need to come out and defend their design (or accept mistakes) is understandable. It is an opinion that is likely to be shared by nearly all jingos (including me). However, with your experience, you are in a better position to understand that this is not how India's defence estabilishments (including Armed Forces, MOD, PSUs etc) work. Unfortunately, they do not seem to understand the value of PR. And frankly, I do not see why ADA (or anyone else for that matter) should bother to respond to a prejudiced criticism in an XYZ magzine. It would only result in giving importance and limelight to this particular article. If the article was published, say in IEEE, then that certainly would have demanded a response. However, I must admit that ADA or retired designers should give some insight into the reasons behind the choices made. However, as you very well know, PR has sadly never been our forte.

indranilroy,
My understanding is that Proff Das specifically speaks out against FBW and Delta.
However, that is not my main point of contention. My point of contention is his accusation that LCA designers were just stupid enough to fall into the west's marketing ploy. It is as if they were some school children who said saw some discovery channel program on Western technology and went
"Wow! FBW! This thing is dope! Lets draw a pretty looking plane on paper and we'll build a FBW for it and make it fly".
My post on the previous page was exactly to point out how ridiculous this statement is.
Last edited by Gaur on 24 Oct 2010 22:32, edited 1 time in total.

D Roy
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Re: LCA News and Discussions

Postby D Roy » 24 Oct 2010 22:31

Anyway here's an early LCA design with the cranked arrow.

http://www.secretprojects.co.uk/forum/i ... 4909;image

via Elider at secret projects who got it from AW &ST

Image

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Re: LCA News and Discussions

Postby AJames » 24 Oct 2010 23:11

indranilroy wrote:I find the Tejas compound delta difficult to understand. I can easily understand the cranked arrow formation, ogee delta. The canards are similar in functionality like the leading edge extensions of the cranked arrow design.

However, the Tejas wing is just opposite to all this. Please let me know (anybody for that matter) if my understanding is flawed at any point. But does the join between the two deltas actually become the point where the vortex is created. I can see that the Tejas does have vortex generators near the join in the form of the red strip (it was flagged here before by some posters as cracks). In between the bleed channel creates vortexes over the "inside" part of the wing. This is definitely a desirable characteristic which will considerably push up stall angles. Besides the stall will start at the wing root which is also desirable.

However, having the inside delta having a lower sweep angle, increases the AR which is not ideal for the manoeuvrability. Is this a tradeoff?


The reason why the reverse cranked arrow wing was used in the LCA (ie. with the root sweep less than the rest of the wing rather than greater in the case of LERX wing root extensions) was to ensure controllability at high AOA. One of the nasty characteristics of deltas is that at high AOA the flow flips suddenly from a LERX vortex generated at the wing root, to air flowing straight over the fuselage. It is not so much a problem if wing stall, but of maintaining pitch control of the aircraft when this happens. This was a problem with the SAAB Draken and the SAAB Viggen had an LCA like reverse crank in its wing presumably to avoid this problem. The Mirage 2000 has strakes just ahead and above the wing to try to prevent this by forcing the vortex at all times. The Kfir used small fixed canards in the same place to direct the airflow backwards to delay the flip in airflow.

The LCA uses a high wing, vortex generating air spill slot and reverse crank to ensure controllability. as for high AOA capability, controllability is far more important than MiG 29 style extreme AOA capability, and a vortex flap fitted LCA should allow more extreme AOA if required.

By the way I do agree with the prof's comments of trying to over specify aircraft. Death by over specification has often killed many potentially decent aircraft - the latest examples being the F22, which has been capped, and the F35 which costs way too much and isn't performing as promised. That is why Sweden have been able to come up with so many good aircraft despite being a small country. The reason is the sensible and pragmatic specifications and mission requirements they come up with for their aircraft. They know they are a small country with limited resources, so they reach the best and most achievable compromise rather than try to specify the moon.

Personally I think the LCA Mk 2 will be the right aircraft for the IAF and will not become obsolescent as some have been claiming, at least for a long time. In the Cope exercises, the Americans were most impressed by the effectiveness of two aircraft in particular. One was the SU 30 and the other was the updated Mig 21 Bison. The latter was small, fast and had a good jammer and was difficult to intercept. The Bison like the LCA is also the world's most stealthy aircraft in one - visual stealth. In an environment where attacking stealth aircraft like the F22 turn off their radars in order to remain stealthy, visual stealth becomes important. A PAK-FA using its long wavelength radar to detect stealth aircraft and handing off attack vectors to LCAs, will probably be the most effective way of combating stealth aircraft.

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Re: LCA News and Discussions

Postby Indranil » 24 Oct 2010 23:42

AJames, thanks for the explanation.

D Roy, that one hell of a looker :).

Shiv sir, a canard can act like a chin and also act as a stabilator for pitch control. In extreme cases it can be used to induce roll

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Re: LCA News and Discussions

Postby vic » 25 Oct 2010 01:02

It seems that India has also dropped Delta Wing in AMCA, as per the public models displayed lately.

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Re: LCA News and Discussions

Postby Kartik » 25 Oct 2010 04:24

vic wrote:It seems that India has also dropped Delta Wing in AMCA, as per the public models displayed lately.

That was supposedly more to do with low-observability concerns rather than due to any problems as such with a delta wing. The original plan and the plan even till AI-09 revealed the latest wind tunnel model was to use the LCA's wing scaled up for the MCA, which indicates that after a bunch of flight tests, they had no real concerns about the wing as such.

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Re: LCA News and Discussions

Postby Viv S » 25 Oct 2010 04:35

AJames wrote:In an environment where attacking stealth aircraft like the F22 turn off their radars in order to remain stealthy, visual stealth becomes important. A PAK-FA using its long wavelength radar to detect stealth aircraft and handing off attack vectors to LCAs, will probably be the most effective way of combating stealth aircraft.


I don't think LPI radars like that on the F-22 need to be turned off to retain stealth. That said, I agree that the Tejas will be a very lethal platform under a PAK-FA umbrella.

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Re: LCA News and Discussions

Postby ArmenT » 25 Oct 2010 04:51

indranilroy wrote:You guys are confusing what Prof Das said. He didn't speak out against FBW as a technology. He says that the weight of the equipments for FBW stays the same immaterial of the plane size. So a light plane takes a relatively higher penalty (weight gain percentage wise). However there are ample examples of planes designed in the past without FBW which were sufficiently maneuverable. Also given a light plane one enjoys a higher TWR (typically) and hence can overcome some limitations by not having the FBW.

Correct me if I'm wrong here, but I thought the whole reason why there is an FBW system on the LCA is because the design is inherently aerodynamically unstable in the air. Most modern fighter aircraft, since the F-16 pioneered it, has been an unstable design.

So if they'd designed the LCA to not use an FBW, they would have to make the aircraft design to be aerodynamically stable and then DDM (and perhaps, Prof. Das) would have been all over the place claiming that India has designed a 2nd generation fighter when the rest of the world is moving to 5th generation fighter.

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 06:06

AJames wrote:
The reason why the reverse cranked arrow wing was used in the LCA (ie. with the root sweep less than the rest of the wing rather than greater in the case of LERX wing root extensions) was to ensure controllability at high AOA. One of the nasty characteristics of deltas is that at high AOA the flow flips suddenly from a LERX vortex generated at the wing root, to air flowing straight over the fuselage. It is not so much a problem if wing stall, but of maintaining pitch control of the aircraft when this happens. This was a problem with the SAAB Draken and the SAAB Viggen had an LCA like reverse crank in its wing presumably to avoid this problem. The Mirage 2000 has strakes just ahead and above the wing to try to prevent this by forcing the vortex at all times. The Kfir used small fixed canards in the same place to direct the airflow backwards to delay the flip in airflow.


In fact this is the best explanation that I have seen. There was once a poster called Abhimanyu on this forum. A person with the same name has laid down similar explanations on some forum. Need to search for the link.

I am no aviator, but as far as I know there is one situation in which every aircraft that takes off needs to fly slow and low with a high angle of attack and this has absolutely nothing to do with combat maneuverability. It's about landing the aircraft. If a delta winged aircraft tends to be unstable at low altitude (perhaps because of low wing loading responding vigorously to gusts?) and does funny things at a high angle of attack there appear to be various solutions to achieve control of the aircraft in the pitch axis. One is to have a tailplane or canards. Other solutions are to add strakes as in the Mirage 2000 and it appears that the unique cranked double delta with its FBW controlled moving surfaces (name??) are a solution. If the proof of the pudding is in the eating the LCA has been praised for its handling.

Oh yes I have heard about deltas slowing down in turns. I have also heard the argument that most air combat (for India, Israel) occurred at low altitudes. But hello? Let's look at the other side of the coin. Remember what happened at Kargil? Aircraft like the Jaguar just did not have the wing surface area (do you guys call it wing loading?) to maneuver nimbly around mountains. And we are talking a mere 15-20 thousand feet here. The monstrous high altitude bomber the B-36 "Peacemaker" with ten engines was said to have been more maneuverable than any US fighter of the day at high altitude. I have also heard the story that the Vulcan bomber could out maneuver a lot of nimble fighters at high altitude. In fact this is why the US had the pure delta F-102 Delta Dagger as the backbone of its high altitude bomber interception force right up to the 1980s. This is also why the French made the Mirage III (as per the good Prof Das himself).

Now guess what altitudes we might see combat over Tibet?
    1) 1,000 feet above sea level?
    2) 5,000 feet above sea level?
    3) 20,000 feet above sea level?

The question of exactly which aircraft that are highly maneuverable at sea level remain equally highly maneuverable at 15,000 feet is usually fudged and dismissed in jingo conversations by statements like "Modern engines with high power and modern TV controls have made all that talk obsolete." But hey the air at 15,000 feeet has not become any more dense and every square inch of extra wing area you have adds to maneuverability. Forget air combat. An aircraft that can maneuver around peaks at 15000 feet is stealthy because it is hiding behind mountain peaks. So the LCA's delta and FBW may not be such a bad choice after all.

And remember that new stealthy aircraft are no longer being designed to fly in at low altitude. If you have an aircraft that is less maneuverable at high altitude fighting a delta that is more maneuverable at high altitude, one great solution is for the former to quickly descend to lower levels where it can outmaneuver the delta. But, excuse me, in Tibet you will hit the ground at 15,000 feet. Heck the fighter lobby is so powerful that a combat maneuverability face off between the monster B-36 and a fighter were disallowed. Imagine how the reputation of a lot of fighters would have been dragged through the mud if they had failed? :shock:

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 08:09

Without getting into an argument about what anyone may interpret from Das's words, there is, to my mind one possibility that could involve the ego of a designer. The scenario I am writing is totally hypothetical and not based on any real event or personality that I know of. But it is a possibility.

Imagine a designer tasked with developing FBW technology and this designer wants to prove beyond any doubt that he is capable of designing a FBW aircraft. What could be the best proof of his capability? In my view the best proof of his capability would be to select an aircraft configuration that is highly (or totally) dependent on FBW. If he selects such a configuration and eventually comes up with a safe, flying and performing aircraft - all glory is his because anyone including the Wright brothers could design an aircraft that did not need FBW - but here he is - demonstrating an aircraft which will not fly at all (or will not fly well) without FBW. What I am talking about here is the "egotistical designer". But the risk here is that if FBW fails or is delayed - the entire project is delayed. It is a calculated gamble whose success brings glory to the designer as well as meeting requirements.

One can similarly cook up a scenario of the non egotistical designer. Here the designer looks for a design that will still fly even if there are delays and hold ups in the development of FBW systems and algorithms. It is an aircraft design that is not totally dependent on FBW but can be usefully flown without FBW while development of FBW for the same airframe goes on in parallel. So he manages to hand the air force something on time while incremental FBW developments are made.

Both routes require a different type of courage. One could argue that the latter designer was looking at providing the air force with a flyable light combat aircraft in a realistic time frame even if his development of FBW was delayed. The FBW development could be added on to an existing working airframe as development proceeded. The former designer tied down the whole program to his development of FBW.

To me, Das's insinuations about not having any "Distinguished scientists" and giving credit to all after the plane is delivered and accepted by the customer seem to suggest that something like the above hypothetical scenario may have occurred in India. So it is not as if all Indian designers "bought snake oil". One guy in a senior position may have thought "OK. FBW is the best. I will show everyone what FBW means by selecting a tough design that demands mandatory FBW and make it fly. That'll learn 'em". Who in India will admit it if this is what actually happened? There is much material to suggest that something of the sort, involving egos and unrealistic goals has happened.

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Re: LCA News and Discussions

Postby Wickberg » 25 Oct 2010 08:30

In the late 1980s SAAB asked India if they wanted to participate in the Gripen project. India rejected.. Hmm, wonder who is sorry now...

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Re: LCA News and Discussions

Postby Kartik » 25 Oct 2010 08:48

Wickberg wrote:In the late 1980s SAAB asked India if they wanted to participate in the Gripen project. India rejected.. Hmm, wonder who is sorry now...


show the link to back that up.

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Re: LCA News and Discussions

Postby Viv S » 25 Oct 2010 08:53

Wickberg wrote:In the late 1980s SAAB asked India if they wanted to participate in the Gripen project. India rejected.. Hmm, wonder who is sorry now...


Certainly not India. If the object was to license produce aircraft (which is probably what the 'offer' really amounted to), HAL has been doing it for years from the Folland Gnat to the Su-30MKI. But, the R&D cycle in aerospace research cannot be purchased or imported like the final product. Which is why India has limited expectations from the PAK-FA/FGFA in terms of growth of indigenous R&D capability.

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Re: LCA News and Discussions

Postby merlin » 25 Oct 2010 09:02

shiv wrote:In fact this is the best explanation that I have seen. There was once a poster called Abhimanyu on this forum. A person with the same name has laid down similar explanations on some forum. Need to search for the link.


In the old forum (circa end 1997) there was a poster with the handle Siva Mahalingam who had posted a wonderful explanation of the flow separation problem at high angles of attack and how the LCAs wing design handles it. That explanation made logical sense and is what the poster AJames also talks about. Unfortunately I only have a printout of that post somewhere, obviously no link.

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 09:04

Was this posted here?
http://www.bharat-rakshak.com/NEWS/news ... wsid=13653
While the indigenously developed Light Combat Aircraft, Tejas, is expected to receive operational clearance in the next two months and its induction into the IAF is scheduled for next year, ...
<snip>
On the status of the Tejas project, Subramanyam said the aircraft trials for launching R-73 short-range anti-aircraft missiles and 1000 lbs bombs have been successful. “The 10 prototypes and pre-production variants have undertaken 1,450 sorties, which include about 200 with weapons,” he said.

The IAF has projected a total requirement for about 120 Tejas and 16 two-seater trainer variants for equipping seven squadrons, while the Navy wants 57 aircraft of this type.

The ADA is also looking at integrating the Israeli Python air-to-air missile with the Tejas to meet the IAF requirements, while the Navy wants it to examine the possibility of the Israeli Derby missiles that it already uses on the Sea Harrier. The Tejas’ avionics system, Subramanyam said, was open-ended so that weapon systems could be changed over seamlessly.

Of the 200-odd Tejas to be produced, each of which would cost Rs 200 crore, about 100 would be powered by the American General Electric 414 engine. Subramanyam said that a new project had been taken up for the development of the Kaveri engine in collaboration with French firm SNECMA that would meet the revised weight and flight parameters of the Tejas.


15% of flight tests have been with weapons. Operational clearance in 2 months.

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 09:09

merlin wrote:
shiv wrote:In fact this is the best explanation that I have seen. There was once a poster called Abhimanyu on this forum. A person with the same name has laid down similar explanations on some forum. Need to search for the link.


In the old forum (circa end 1997) there was a poster with the handle Siva Mahalingam who had posted a wonderful explanation of the flow separation problem at high angles of attack and how the LCAs wing design handles it. That explanation made logical sense and is what the poster AJames also talks about. Unfortunately I only have a printout of that post somewhere, obviously no link.


Ah - now I recall that. Unfortunately I was even more stupid in those days than I am now and did not give a damn about flow separation unless someone's prostate gland had similar issues.

In fact all this canard shanard business is about pitch control. That is done by the oddball wing design on the Tejas. I imagine that the Tejas may well have been conceived by an egotisical, now retired designer. If he had delivered FBW 10 years earlier we would probably have a name and a Bharat Ratna attached. Defeat is always an orphan.

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Re: LCA News and Discussions

Postby Indranil » 25 Oct 2010 09:37

Wickberg wrote:In the late 1980s SAAB asked India if they wanted to participate in the Gripen project. India rejected.. Hmm, wonder who is sorry now...


Wickberg ... this is nothing but flame baiting!!!

Besides I dont think there are very many people in India who are "sorry" about not joining the Gripen project.

One day we had to design and build our own planes with our own avionics and weapons and engines. The sooner we started the better ... so if anything I atleast am proud and happy that we didn't join the Gripen project! And as far as I know many people here would feel the same! :D
Last edited by Indranil on 25 Oct 2010 10:05, edited 1 time in total.

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Re: LCA News and Discussions

Postby negi » 25 Oct 2010 09:37

How many fighter aircraft designs were conceived during/after 80's that do not use FBW (analog/digital) ? That should suffice as answer to Professor's query on reason to go for FBW . As for the Delta wing, Tejas's french connection during the nascent stages is a known fact so commonality in design philosophy is very much possible.

--typos
Last edited by negi on 25 Oct 2010 09:58, edited 2 times in total.

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Re: LCA News and Discussions

Postby Indranil » 25 Oct 2010 09:38

merlin wrote:
shiv wrote:In fact this is the best explanation that I have seen. There was once a poster called Abhimanyu on this forum. A person with the same name has laid down similar explanations on some forum. Need to search for the link.


In the old forum (circa end 1997) there was a poster with the handle Siva Mahalingam who had posted a wonderful explanation of the flow separation problem at high angles of attack and how the LCAs wing design handles it. That explanation made logical sense and is what the poster AJames also talks about. Unfortunately I only have a printout of that post somewhere, obviously no link.


Please scan it and upload it [I wish there was an emoticon with folded hands or something like that]

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 09:40

Some loud thinking here

The Jaguar was designed as an aircraft that would fly steadily at very low altitude. It's performance at high altitude is AFAIK poor. Compared to its loaded weight, its wing area is small - giving a wing loading of 456 kg/sqm. Just enough wing to provide lift at fairly high speed at low level with less buffeting.

The Tejas OTOH has a wing loading of 247 kg/sqm. That means that the Tejas has a lot more wing area per kilo of weight. More wing means it can get blown up and down and buffeted at low level as the wings act like a sail. But take the guy high up and he rules in the thin air. It has a lot more wing for lift and the delta design (I am told) inherently protects the wings from supersonic airflow.

Design choices are very interesting. When I read about the Tejas it strikes me that there seems to have been an early disconnect between designer and user. The designer (DRDO) was looking to develop the technology. The user IAF was looking far a modern aircraft to replace the MiG 21. They were looking for a usable weapons system in a clear time frame.

If you are looking only at developing technology - you cannot set a time limit
If you are looking for a replacement weapons system, there is a very very definite time limit. It must be delivered on time.

If you combine the two aims "development of technology" and "delivery of weapons system" - they you are causing a problem. The delivery of the weapons system gets delayed if the technology does not come on time.

For all Indians this should be the big take away lesson. Never subvert the delivery of a weapons system while waiting for technology. You may have to fight tomorrow, technology or no technology.

Ideally - learn to deliver weapos systems that work and whaich can then be gradually modified and adapted to use technology as it is developed.

This is what was done for the MiG 21
This si what was done for the Jaguar.

Sadly, nobody thought of this while the LCA saga evolved. If there is a God I ask her to make sure this does not happen again in my country.
Last edited by shiv on 25 Oct 2010 09:41, edited 1 time in total.

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Re: LCA News and Discussions

Postby vina » 25 Oct 2010 09:41

shiv wrote:One can similarly cook up a scenario of the non egotistical designer. Here the designer looks for a design that will still fly even if there are delays and hold ups in the development of FBW systems and algorithms. It is an aircraft design that is not totally dependent on FBW but can be usefully flown without FBW while development of FBW for the same airframe goes on in parallel. So he manages to hand the air force something on time while incremental FBW developments are made.


Ah. Look up the top view of an F-16 and you can see that where the wing joins the fuselage, it basically is a straight parallel section. The F-16 was designed such that in case the FBW thing wasn't successful, the Plan B was to move the wings back by a couple of inches to make it a conventional plane !

Both routes require a different type of courage. One could argue that the latter designer was looking at providing the air force with a flyable light combat aircraft in a realistic time frame even if his development of FBW was delayed.


Well, once the FBW thing was proven on the F-16 and the brit Jaguar test bed platforms such as M2K came out, there was no way in hell you could have come up with a competitive product WITHOUT FBW. So lets come off this thought of having a product without FBW and able to meet specs.

Don't point out the Mig29A/B. Despite all the Rahh Raah by the fan boys, it doesn't cut the mustard except in certain limited regimes and with serious limitations of range , payload and persistence. The current Mig29 versions are basically totally new airplanes under the skin.

And also, the specs for the LCA must have been pretty tough with maneuverability specs to meet or beat the F-16 Blk 10/15 (which to this day are probably the best in the business), considering that in 1984 the Pakistani F-16s were the ones for the IAF to beat .

In fact, I think Austin posted Subharamanyam's interview where he admitted to a shortfall or two with the current engine from the original LCA ASR because of weight gain and how the IAF has agreed that in this day and age with all aspect and off boresight missiles that requirement is not as critical as it was in 1984. It is not very difficult to guess what he was referring to. It is sustained turn rate that will not be met with the current engine and probably take off run distance as well. Those two will need the uprated engines.

See, this is what the Mig29 with its traditional stable design did to meet the F-16's sustain turn rate . They installed lot more excess thrust than it would have needed if it was an unstable design and gave up on payload and range.

If in a conventional design and metal fuselage, we wanted a plane to take on the F16s and the original 80KN GE engine, yes possible, but you will have a plane with the endurance of a Mig 21 and probably similar payload and such a plane would have been dead on arrival, and at best be the equal -equal of the JF-17 Bandar the Cheenis have cooked up for the Pakis.

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Re: LCA News and Discussions

Postby vina » 25 Oct 2010 09:43

Wickberg wrote:In the late 1980s SAAB asked India if they wanted to participate in the Gripen project. India rejected.. Hmm, wonder who is sorry now...

Thank goodness we rejected. Otherwise, we would have got kicked out of the program and have no plane at all after 1998! The same reason why India rejected the Saab Viggen still holds. The Swedish products are prone to American sanctions. Sweden can be a player only if the Indo-US relations are straightend out. But then the big question will be why buy swedish at all, when there are far better choices available from America directly! :mrgreen: :mrgreen:

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 10:10

vina wrote:Well, once the FBW thing was proven on the F-16 and the brit Jaguar test bed platforms such as M2K came out, there was no way in hell you could have come up with a competitive product WITHOUT FBW. So lets come off this thought of having a product without FBW and able to meet specs.


This is true.

A lot of things are easier for me to say now that India successfully has FBW in its pocket. The dilemma for India in the 1980s was the need to develop technology without which specs could not be met. Ideally this would have meant the developer sitting with the end user and saying "Look we can offer no guarantee of getting that tech and those specs in your timeframe. We can do less than that and upgrade as tech becomes available"

The Air Force was contemptuous in those days. HAL may have been less than "up to par" and DRDO had filled itself up with people who promised the moon. There is a big engineering and tech jump from licence produced Gnat (Ambassador) and flying Tejas (Nano). India has moved on.

Hopefully those particular attitudes have been corrected and errors will not be repeated.

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Re: LCA News and Discussions

Postby Singha » 25 Oct 2010 10:18

in my opinion technology demonstrators/univ projects are easier and less stress than delivering working products that customers will deploy and do a lot of things with (some of which will be -ve testcases). that is why there are tons of universities churning out papers and studies and prototypes and only much smaller number of successful product cos in the real world. close 'engagement' with big customers is essential and thats what most CxO's do.

without IA/IAF buy in from day1 and involvement, its a tough hike. they also need to have big R&D and design offices like the navy does and employ engineers and scientists there. I guess IAF has it in a way with ASTE?

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Re: LCA News and Discussions

Postby Pratyush » 25 Oct 2010 10:26

Why not have an agency whose sole job is to dream up concept aircrafts like concept cars and present then to the end users for evaluation. If the user thinks that it will meet a specific need then it gets further developed else back to the drawing board.

The Idea is to keep the designers & systems men always at the leading edge of the technology.

Sort of our own X planes project.

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Re: LCA News and Discussions

Postby negi » 25 Oct 2010 10:42

Vinaji BAAZ has its fan following for a reason.

http://www.scribd.com/doc/21520658/Mira ... -same-team

To quote Air Marshall Harish Masand (First Supersonics)

I only remember that the 29 outperformed the Mirage in every sphere from sustained rate of climb and even instantaneous rate of turn


He clearly says that they expected M2k to have better instantaneous turn rate but during the trials the 29 came out on top. Another noteworthy point he makes is that despite being powered with two fuel guzzling engines the Mig consumed equal amount of fuel as the Mirage during the duel as it did not have to engage the afterburners.

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Re: LCA News and Discussions

Postby vina » 25 Oct 2010 11:56

negi wrote:Vinaji BAAZ has its fan following for a reason.

http://www.scribd.com/doc/21520658/Mira ... -same-team

Great write up and everything he said is absolutely correct. His perspective is of a pilot flying an air defense/superiority mission and a more limited mandate of evaluating air to air performance in certain regimes.

Yes, it is precisely in stuff like sustained turn rates, climb rate, take off run etc, the Mig29 will be much better than the Mirage 2000!

But what is more instructive is not what he has said but rather what he has
NOT said
, though he refers to it obliquely.

The M2K is a far smaller plane than the Mig29, yet, it has a far higher range and payload and a very strong A2G capability in addition to a pretty competent A2A capability!

So it is like this. If you want a plane that can do drop some 2tons of bombs some 500 Km away and fight off enemy fighters and return home you want the Mirage 2000. If you are a fighter jock defending your airspace against intruding F-16s or other strike aircraft, you want the Mig 29! Similarly if you want to provide fighter cover to a 4 ship formation of Jaguars/Mig27s going deep into enemy territory , you need the M2K (or better still the SU-30).

Now the only problem with the M2K is it's single shaft old tech engine and it is short of some 25KN of installed thrust, that handicaps it in A2A .

However the F-16 has a beast of an engine (especially the latest ones) and has more than enough installed thrust to take on and maybe beat any Mig29 in A2A , while having all the exact same advantages of the M2K of going 600miles into enemy territory and dropping some 2Tons of ordnance and fighting off fighters and coming back home , and of course the F16 (early ones) too is a much smaller machine than the Mig29.

See, that is the difference that FBW made to the M2K and F-16. Lets put it in another perspective . The gist of which is this.

The Mig29A/B is an aircraft of the dimension and installed thrust in the Rafale /Eurofighter class, but with a far far shorter range and much less payload than the F16 and M2K. The lack of FBW in the early Mig29sA/B clearly told on their overall performance.

This is not even talking about the carefree flying of the M2K vs the Mig29 the lack of FBW and FADEC on the Mig29 that the article talks about !

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Re: LCA News and Discussions

Postby merlin » 25 Oct 2010 12:39

shiv wrote:For all Indians this should be the big take away lesson. Never subvert the delivery of a weapons system while waiting for technology. You may have to fight tomorrow, technology or no technology.


In the context of the LCA, I disagree. You are never going to catch up with the lost decades and technology if you are doing more of the same. You need to leapfrog generations and that requires ambitious jumps. Just creating a MiG-21 replacement would not have been enough given that we had, myopically as it turns out, dropped fighter development after the Marut.

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Re: LCA News and Discussions

Postby Singha » 25 Oct 2010 12:45

>> You may have to fight tomorrow, technology or no technology.

that is the "user pov" articulated by iaf and ia on occasions. all the super tech in TD/proto/drawing board stage has no meaning when they have to fight a war. it needs to work and it needs to work today!

however strong nations and their militaries do expend some effort in "supporting" domestic goods and projects and improving them step by step until they match or better off the shelf stuff. US could easily have setup a license plant for Leopard2 , added some own gadgets yet they went to expense of a full tank program. likewise they could have imported excellent european howitzers like Pzh2k but tried to do something better in crusader...israel stuck it out with merkava....UK with its SSN program...france with its SLBMs...

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Re: LCA News and Discussions

Postby Kanson » 25 Oct 2010 12:52

Arguments can be made for & against FBW..

Nightmare of designers involved in a/c development is the crashing of prototypes. Indigenous a/c development programme came to halt after the Marut crash. What could have happened if such thing happened in the early stages of LCA? With our media with foreign weapon collaborators and ever loving foreign maal army, it could have killed the programme there itself. FBW guaranteed safe handling of the a/c during flight testing. Even though it can be said by anyone with the advantage of hindsight, FBW delayed the first flight, it can't be denied that it helped in avoiding any mishap which must have set the programme to abandon in worst case scenario.

There are pros & cons for any decision. I see no point with the Prof's argument as the weight he chosen as standard for comparison is not correct as he used that weight criteria to pick at FBW.

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Re: LCA News and Discussions

Postby Kanson » 25 Oct 2010 13:12

shiv wrote:
vina wrote:Well, once the FBW thing was proven on the F-16 and the brit Jaguar test bed platforms such as M2K came out, there was no way in hell you could have come up with a competitive product WITHOUT FBW. So lets come off this thought of having a product without FBW and able to meet specs.


This is true.

A lot of things are easier for me to say now that India successfully has FBW in its pocket. The dilemma for India in the 1980s was the need to develop technology without which specs could not be met. Ideally this would have meant the developer sitting with the end user and saying "Look we can offer no guarantee of getting that tech and those specs in your timeframe. We can do less than that and upgrade as tech becomes available"

The Air Force was contemptuous in those days. HAL may have been less than "up to par" and DRDO had filled itself up with people who promised the moon. There is a big engineering and tech jump from licence produced Gnat (Ambassador) and flying Tejas (Nano). India has moved on.

Hopefully those particular attitudes have been corrected and errors will not be repeated.


As you probably know, LCA is not only about providing weapon for the Airforce, It was also meant to revive the aero mil industry and leapfrog the tech advancement that was lost in previous decades. If you have observed, it was not DRDO, the whole India & institutions is behind the LCA national programme. Pls go throu' ADA & LCA history before making snide comments.

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Re: LCA News and Discussions

Postby Lalmohan » 25 Oct 2010 13:15

it would seem logical for even the 50 odd Tejas currently ordered to be rushed into service and allow time for the IAF and HAL to learn how to do these things better. it doesn't matter if the technology is not perfecet, but there is still a lot to be learned in terms of certification, airworthiness, operational logistics, maitenance, repair, deployment, etc., etc. by going through these cycles we'll be in a better place to develop and induct Mk2 and then FGFA, etc. Same applies to MMRCA
instead of perfect theoretical answers, we need to get very practical - we need to have sufficient sword strength available to counter any belligerent moves from the north and west

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Re: LCA News and Discussions

Postby Austin » 25 Oct 2010 13:57

vina wrote:However the F-16 has a beast of an engine (especially the latest ones) and has more than enough installed thrust to take on and maybe beat any Mig29 in A2A , while having all the exact same advantages of the M2K of going 600miles into enemy territory and dropping some 2Tons of ordnance and fighting off fighters and coming back home , and of course the F16 (early ones) too is a much smaller machine than the Mig29.


The latest F-16 is nothing but a bunch of heavy rock that some how manages to fly after Block 30 the F-16 just got heavier and in turn it was compensated by higher thrust ,has higher wing loading and it just went that way , compromising its basic flying qualities and dog fighting capability and making it into strike fighter with BVR to the rescue.

The Mig-29 on the other hand just got better from 29A to 29S ,29M/M2 ,29K and 35 , with latter generations it got better multirole capabilities , better engine and better avionics/sensors and never compromised its basic flying qualities that it was designed for which was to be a good air superiority fighter and to excel in Dog Fight.

Now coming back to 29A , the main problem with that fighter was its fuel guzzling engine ( remember we are talking of mid 80's ) which affected its persistent in air , FBW or no FBW was not the real problem because as a design the 29/27 was far ahead of its time , as you can see from its evolution from 29A to 35 and Su-27 to Su-35 they just got better, give the 29A an RD-33MK and it will have better persistence.

And I do not recollect any 29A ever got torn up in mid air because FBW awarded better safety , AFAIK the 29 metal structure was designed to withstand 12g and as you can see 29 is being upgraded at the same time the Mirages are in IAF , so though Mirage has better built quality if you maintain the 29 well they were up to the task as well.

IAF routinely does fighter cover using Mig-29 for Jags/Mig-27 and it can do that job quite well as much as it can do a dog fight , the R-27 certainly has a much longer range then any Matra R-530.

So to sum it up do not compare a Mig-29 with Mirages , the M2K is a better multirole fighter by design and doctrine of French/NATO as much as Mig-29 is a better Air Superiority Fighter by design and doctrine of Soviets. They both were designed in a era to meet French/NATO and Soviet/Warsaw requirement and excelled in what they did.

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Re: LCA News and Discussions

Postby vina » 25 Oct 2010 16:09

Austin wrote:The latest F-16 is nothing but a bunch of heavy rock that some how manages to fly after Block 30 the F-16 just got heavier and in turn it was compensated by higher thrust ,has higher wing loading and it just went that way , compromising its basic flying qualities and dog fighting capability and making it into strike fighter with BVR to the rescue.


Yes, this part is true. The F-16 is at the end of it's evolution and cant go beyond this.

The Mig-29 on the other hand just got better from 29A to 29S ,29M/M2 ,29K and 35 , with latter generations it got better multirole capabilities , better engine and better avionics/sensors and never compromised its basic flying qualities that it was designed for which was to be a good air superiority fighter and to excel in Dog Fight.


Yes, the getting "better" part is true. But the real picture is HOW it got better .

Now coming back to 29A , the main problem with that fighter was its fuel guzzling engine ( remember we are talking of mid 80's ) which affected its persistent in air , FBW or no FBW was not the real problem because as a design the 29/27 was far ahead of its time , as you can see from its evolution from 29A to 35 and Su-27 to Su-35 they just got better, give the 29A an RD-33MK and it will have better persistence.


But this part is unfortunately totally off the mark. The RD33 is a twin spool engine and at the worst case, it will do as bad as the single spool Snecma engine in the M2K in terms of fuel economy. The Mig 29A has terribly short legs because of the piss poor fuel fraction ,a short coming it suffered together with the F-18 (which in fact had the excellent GE F404 engines).

And no, you wont get the original Mig 29 upto scratch just because you put the RD-33MK engine. What brought the Mig29 upto scratch was the addition of a extra saddle fuel tank (giving it a platypus back), making it unstable by moving the wings forward and then putting in an FBW for control (and that along with the additional equipment for A2G and upgraded systems such as EW etc).

There is really no "secret" here . The Mig29 was a Rafale/Eurofighter sized plane with a similar thrust engines, but with "degraded performance " than what would have been possible if there was an FBW/unstable layout. RAC Mig did just that with the new FBW and sytems and "liberated" the repressed performance potential to get it closer to the Eurocanards in the latest versiosn . Essentially below the skin the latest Mig29 is a totally different plane, while the F-16 is rather the same old plane.

And I do not recollect any 29A ever got torn up in mid air because FBW awarded better safety , AFAIK the 29 metal structure was designed to withstand 12g and as you can see 29 is being upgraded at the same time the Mirages are in IAF , so though Mirage has better built quality if you maintain the 29 well they were up to the task as well.


Ultimate static limits are 12g for the western fighters as well. But if you exceed the designed 9g, the plane is basically going to a write off at worst or at best is going to spend a lot of time back in the hanger for serious structural repairs.

So to sum it up do not compare a Mig-29 with Mirages , the M2K is a better multirole fighter by design and doctrine of French/NATO as much as Mig-29 is a better Air Superiority Fighter by design and doctrine of Soviets. They both were designed in a era to meet French/NATO and Soviet/Warsaw requirement and excelled in what they did.


What I was comparing is design choices and HOW the performances were achieved. The F-16 is all in all a lot more efficient platform. The Mig29 and SU-27 are the same philosophies as the losing YF-17 and the F-15 . The YF-17 when it was resuscitated as the F-18 featured an FBW!

The Mig 29 is the best the soviet industry could manage at that stage given it's capabilities with computers and electronics that needed to be miniaturized. The Soviets took the twin engined "loser" design wise ( equivalent to YF-17) in the light fighter contest and bulked it up to get it the equivalent A2A performance of the F-16 (the winner).

Bottomline, Today you need FBW. No FBW , you have a bloated pig that is well below the perfomance possible.


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Re: LCA News and Discussions

Postby Philip » 25 Oct 2010 16:56

One pertinent point which I've brought up before is the dogfighting cability.The Israelis still train their pilots extensively for close combat and retain their cannon despite advances in BVR missiles,simply because most air combat takes place in the transonic arena and if one has managed to successfulluy evade a BVR missile,then what happens next? This is why the "cobra" manoeuvre in Russian fighters like the MIG-35 and SU-27/30s is not just an airshow trick but used during dogfighting to "toss" a missile backwards against the enemy.It is why some fighters also have rearwards facing radar (quoting western sources).

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Re: LCA News and Discussions

Postby shiv » 25 Oct 2010 16:57

Kanson wrote:
As you probably know, LCA is not only about providing weapon for the Airforce, It was also meant to revive the aero mil industry and leapfrog the tech advancement that was lost in previous decades. If you have observed, it was not DRDO, the whole India & institutions is behind the LCA national programme. Pls go throu' ADA & LCA history before making snide comments.


Don't feel upset saar. I will make as many snide comments as my pent up feelings produce seeing that I have been myself following the LCA saga since the 1980s. If snide comments made things better I would have filled the airwaves with them. But your comment about "whole India & institutions is behind the LCA " is onlee partially correct. All that came much mu-uuuch later. And with whole India being behind LCA the IAF is still using MiG 21. That should teach us a few lessons for tomorrow.

I have a fairly good idea of what the IAF and HAL used to think of each other and what everyone said about DRDO is well known and has been discussed on BRF in detail for over 10 years with me being at the forefront of the people supporting and rooting for DRDO and I do not think I need any lessons from you sir. Please keep them to yourself. Thanks

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Re: LCA News and Discussions

Postby Austin » 25 Oct 2010 17:20

vina wrote:What I was comparing is design choices and HOW the performances were achieved. The F-16 is all in all a lot more efficient platform. The Mig29 and SU-27 are the same philosophies as the losing YF-17 and the F-15 . The YF-17 when it was resuscitated as the F-18 featured an FBW!


F-16 was lot more efficient and perhaps less maintenance prone ( although a gentle man from BA told me at aeroindia that SoKo F-16 had an uptime of 70 % ) but it was also a single engine fighter.

One cant just over look the benefit of having a twin engine over a single engine but thats another debate.

The design choice is also influenced by doctrine as much as by technology/capability , had they continued with single engine design and built a better Mig-23 they would not have managed to outbeat the F-16 in some parameter , while a single engine has its own pitfalls , the soviet always had a philosophy of build something and let it evolve over period of time , so a Mig-35 is a better Mig-29 in every possible sense after 30 years but a F-16 Block 60 is not a better F-16 after 30 years in every possible way.

Clearly F-16 with FBW was the benchmark in DogFight for the west and Soviet found Mig-29 to be a better dog fighter with its minus , strangely though Su-27 came with FBW they did not find Mig-29 good enough to have one , which makes me wonder if with FWB Mig-29 would be expensive fighter and not a cheap mass produce one for PD task.

How expensive a FBW aircraft will be for the same design over a non FBW ?


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