Re: ADA LCA Tejas Mark-II
The ADA LCA: Beloved Aircraft or a Lemon
SOURCE : Prof. Prodyut Das / Former Professor Mechanical Engineering IIT Kanpur
Official announcements on the progress of the LCA cause more worry than cheer. The postponements are now routine. In December 2013 we were assured that we should have two aircraft by March 2014. What we got was one aircraft in October. That works out to half of what was promised after a delay of three hundred percent. The delay we are used to; the worry is that after sixteen machines and 2700 sorties is the programme so unsettled that it is difficult to get reasonable dates? FOC by May 2015 is doubtful. The significant overweight will not permit spinning and brake over heating problems to be resolved. At best we might have the end of factory testing and the formation of a Handling Flight. This will be followed by the raising of the first squadron with an IOC. The real troubles will begin then. As the new machines are bedded down in squadron service they require support. If the squadron was raised at AF Halwara or AF Hashimara it would have been a strong endorsement of the LCA's serviceability. By locating it at Coimbatore, 110 n.m. from the nearest border and not a pressing air defence priority but close to Bangalore gives a message that the current in serviceability may be doubtful. The product needs support. If so why not raise the first squadron at Yehlanka?
A Simple Comparison
Given the above the average "LCA Watcher" is better off relying on peasant common sense to evaluate the status of the programme. This below is my assessment and is made from what is available reliable "open source" information. What I have done is to form a table where I have compared the LCA Mk1, with the competition. From the figures emerged some obvious "what if" questions which lead to, simple suggestions of correction.
These below are the parameters I compared with all aircraft in "clean" condition with full internal fuel.
Aspect Ratio (AR) This will give a clue as to which way we should head.
Wing Loading (WL) Clean full fuel weight divided by wing area. Kg/M2\. Gives instantaneous rate of turn.
Power loading (T/W) Engine thrust in kg by above wt. multiply by 10 if you are a Newton's fan. Where two figures are given it is full military and A/B thrusts. The MiG Bison's R25 has two A/b conditions, so two A/b T/W is given. Indicates the aircraft's ability to fight in the vertical plane.
Induced Drag by Thrust (ID)/T Ideally I should have SEP but I have substituted it for ID /T. This is the percentage of engine power used up by induced drag in a 3'g' turn at 350 knots. Gives a fair indication of the aircraft's fighting abilities in the horizontal plane.
S. No Type AR W/L T/W ID/T
1 LCA Mk. 1 1.8 242 0.52/0.84 0.35
2 MiG-21 Bis 2.2 354 0.64/0.87/1.14 0.39/.32
3 F-16 A 3.2 408 0.64/1.15 0.244
4 JF-17 3.7 372 0.48/0.95 0.23
5 LCA (5400) 1.8 212 0.6/0.98 0.28
6 LCA (5400/2.5) 2.5 208 0.6/0.98 0.20
7 Gnat F1 3.6 237 0.71 0.20
8 Super Gnat (Adour) 3.6 286 0.95 0.24
To the average reader the figures are self-explanatory and I will restrict myself to comments after giving the usual caution that such figures are comparisons are for two fighters in vacuo. All kinds of factors play a role in the outcome of any engagement not the least being X vs X combats. My own reactions after studying the figures are these.
First the bad news:
1. We have a fairly mediocre fighter somewhere between the Gnat F1 and the MiG 21 on our hands. Hence the IAF's present reluctance with the Mk.1.
2. Both the F-16 and the FC-17 will give the LCA Mk.1 a hard time. The F-16 A will be particularly dangerous. Even against the FC-17 it would be a Mysteres vs Sabres kind of a situation. I don't have much faith in the "great equalizer" capabilities of BVRs as of now. BVRs is not the weapon for a little LCA. Hence the FC-17 will also be a very dangerous opponent no matter how much we snigger about the Chinese aircraft.
3. As a MiG-21 bis replacement the LCA is a failure because the general rule of thumb is a 15 % increase in performance and capability. The LCA Mk1 does not measure up. The landing speed and the cockpit displays will be better than the early MiGs which will help reduce accidents but let us not fool ourselves of having developed a MiG-21 replacement particularly as an interceptor. So what do we do?
And now the good news – if you are prepared to think differently!
The good news is that the LCA Mk1 is a good replacement for the Hunters, Gnats and Mysteres and to a certain extent the Sukhoi Su-7 that we had in '71. We had a round 23 squadrons of these and the LCA could be a replacement for these ground attack squadrons which to me was always the core of the Air force's business. How do we go about that? The background notes are:
1. As things are going come 2020 the IAF will be forced to use the SU 30MKI or the Hawk for close support. Neither bears thinking, to my mind. The LCA, particularly given its small size will be better in this role.
2. The IAF is allergic about using transonic aircraft after having lost Hunters to MiG 19s and Mirages IIIs at Talhar and the gallant Sqn. Ldr. Mistri's loss is still remembered. However these losses were also due to zeal which should on occasions have been restrained.
3. The IAF has to be persuaded to accept the LCA with minimal improvement confined to improving critical platform performance parameters. The LCA for close support with Su 30 MKIs as top cover could be source of envy and a model to follow for many countries.
4. To obtain that performance improvement the weight of the aircraft has to be reduced to the original target of 5500 kg. If necessary, some equipment has to be deleted. The first to go will be the Flight refueling. FR is an extremely expensive force multiplier and I cannot imagine using FR resources on a "puny" warplane such as a LCA. If the IAF is adamant in its sulk, keep only a small number of LCAs with this facility. I remember developing and producing a Soviet (very "Heath Robinson" but effective!) Arctic heating system for the T 72 (it thawed out the lubricant, fuel and the engine and used the remaining heat to warm the fighting compartment!) for the Army. They equipped only one third of their fleet and we lost a lot of business! There are no hard data on the efficacy of BVRs. The BVR issue has to be debated constructively with may be TACDE help.
Weight improvement is the key
If we accept the above then the question is how much are we going to get by "weight improvement". Item 5 – LCA (5400) is an indication of how the LCA would stack up if we reduced the basic empty weight to 5400 kilos. We see that the LCA (5400) immediately becomes a reasonably competitive aero plane with the other lot. The question is "Can we have an LCA at a basic empty weight of 5400 kilos.
What should be the weight of the LCA Mk 1?
The starting point of this estimate is the airframe of the HF 24. It was 2618 kilos including the cockpit canopy but excluding the undercarriage. My estimate is that the LCA airframe is about 10% smaller and should weigh- in all aluminum- about 2400 kilos. If we now factor in the savings due to use of 65% composites the LCA airframe should be 20% lighter. If not then why are we using a strategically vulnerable material like composites? We don't produce the stuff. So the airframe of the LCA should weigh no more than about 1900 kilos. Let us say about 2000 kilos as a round figure. If we now add:
Undercarriage 250 kilos
GSh 23 mm 50 kilos
Engine 1000 kilos
Ejection seat 90 kilos
Accessories gear box 45 kilos
Radar 130 kilos
Other avionics 180 kilos (including FBW related)
Constant speed drive 40 kilos
ECS 30 kilos
Battery Main and Standby 50 kilos
Generators main and standby 60 kilos
Hydraulics and controls 260 kilos
Total 2185
So we see that when added to the airframe weight we get a total 4100-4200 kilos. This gives a margin of 1.2-1.3 tons for all the remaining weights of brackets, cabling, piping, controls, shrouds and other items. Mind you ADA itself had maintained, for decades, that the basic empty weight of the LCA was around 5500 kg only to spring a surprise before IOC that the thing was 1.3 Tons overweight!
Fuselage lengthening
The requirement of a minimum length of fuselage for a given cross section (CS) to get the desired Cd0 is well understood. I have always maintained that the LCA's fuselage was too short for its CS resulting in a excessive drag. My guess is that at low level she will not do more than M 0.95 for all practical purposes. Most fighters of this genre have had fuselage lengths between 14 and 15 mts at least. I am putting below some figures which you will note relates only to F-404 engine fighters so the influence of the engine length on fuselage length is avoided.
1. Gripen A 14.1 mts.
2. Lavi 14.39 mts
3. F 20 14.2 mts
4. LCA Mk1 13.2 mts.
There are talks of increasing the fuselage length now. This point required pondering long ago, perhaps even as the first layout studies were coming off the printer.
Tweaking the Wing- after block 1!
The LCA suffers from having one of the lowest aspect ratios ever in any fighter resulting in high induced drag in combat. Instead of a major redesign of the wing item 6, gives what would happen if the wing was "tweaked' to have an AR of around 2.5. LCA (5400/2.5). The design conflicts for this would be:
1. Increase the span but with minimum increase in wing area to improve AR. I have increased the span by 1800 mms to 10 meters and the WA goes up to 40 sq. mts – a 3sq. mts increase.
2. Keep the tip width as large as possible (conflicts with minimum area increase above!) in any case not less than 0.5 meters to keep the landing speed Reynolds number within steady flow. Otherwise she will rock/ wobble when coming in. Why overwork the FBW? Some tip camber may be required.
3. The logical solution is a trapezoidal extension. The hand sketch shows half the wing planform. The resultant 'kink' may need a fence/acorn to straighten flows there. Don't invent. Use the MiG-21's fence to start with as the flow number will roughly be same. The V max and the rate of roll may go down by about 5% (visual estimate!) but we would have a fighter which would stand up quite well to the F-16 in a "real world" situation of 2 vs 2 or 4 vs 4. I had made a similar suggestion about tweaking the MiG 21's wing (Indian Defense Review 1990 Vol.2). The Chinese did something on those lines with their F7P clone much later and reported excellent improvements. Remind us that we must insist on design rights in the next FGFA license! What are the remaining items 7 and 8 doing? I will write about them at a later date but for the present they show how much simpler and quicker it would have been for all of us to have based our design on the Gnat with just the smallest of improvements. This should have been seriously investigated then with the AF looking over your shoulders. It would be an excellent aircraft with plenty of potential for people building. It would have also been a short, low cost project which may have been the reason why it was ignored! It is still relevant with excellent export prospects. If you give me a reasonable commission I will do it for you even now and quickly. Of course don't spoil your chances by tailoring it too closely to any single customer. The Vickers people went out of business when for the VC 10 and they listened to BOAC about the "Empire" (hot and high) routes. They got a beauty but it used more power to carry the same number of passengers no faster than the Boeing 707. Sic transit Gloria!
What is to be done?
If we let things continue as they are nothing will happen. ADA is an organization that is risk averse. We have an excellent run so far (touch wood!) of no crashes but there is no prize for that. SAAB, General Dynamics or Airbus are no fools. In any case once the LCA gets an IOC (the actual one) we will have crashes, because nothing is better than the Flying Officer to find obscure design faults in an aircraft. So here goes:
1. This business of maintaining crash free record is to be closed. Crash free development, once you have enough prototypes, cannot continue to be a critical performance parameter. We have already beaten all world records for all times. Let's get real.
2. There are two basic problems with the aircraft. One is the weight and some aerodynamic refinement, the second is the slow production. Let's discuss the second problem first.
3. Get a team which will ramp up the production present faults and limitations and all. The Hunter MK1 was riddled with problems but Hawker's produced 160 of them –warts and all.
4. For ramping up production my humble suggestion, is to get the HJT 36 prototype management team back. They have performed. No sense in spending months and months getting an ideal team.
5. The team's task would be just two. The first is to produce all the forty aircraft as fast as possible. The second is to have by 2016 the plan to roll out LCA's at the rate of 60 per year and to have, by 2018, that capability in place. Even at that rate we will need ten years to complete the anticipated requirement.
6. If resources cannot be found to produce at more than the 14-16 per year then examine seriously whether we should have ambitions to be in this class of aircraft. During the days of "Planned economy" the production rate of scooters was pegged at 100,000 p.a. – well below an economic production rate. It encouraged a thriving black market.
7. There can be no "wait until the design is proved". This is either delaying tactics or lack of confidence. You either believe in the certification process or do not issue a certificate. You can't have a certificate and then go slow. By going too slow we are killing the project by creating a "force majeure" condition where imports may need looking at.
8. Shying away from hidden faults is wrong philosophy. Problems have to be hunted out and exposed by intelligently planned flight tests.
9. The problems are persisting not because of "High Technology" but because of ADA's style of management. How else can one explain that the overweight problem was sat on since 1996? Why was the fuselage extension not handled somewhere between 2005 when the flight trials must have shown up the excessive drag. Weight and drag improvement is not high technology.
10. Limit the development of the LCA to basic experimental development. Don't form a committee to tweak the wing – if at all you want to do a tweak. Study the ferry tips of the Harrier and do a fix using may be wood or, if you must, a foam and e-glass strap on to verify the idea.
The LCA F414 – stop it!
There have been noises about getting the "right" aero plane in the F414 powered LCA. This rings alarm bells of all kinds. A new engine, new ducts, weight increases, new or re written FBW (?), a new rear fuselage. We are hatching another wild goose to chase. The Swedes have increased the fuselage length to 15.2 mts and the internal fuel capacity (by a 1000 kg more than the LCA's) in the similarly powered Gripen E. The LCA's proposed 0.5 mts increase in fuselage length will surely reduce the Cdo but it will not allow fuel capacity increase of more than 250 liters at best. We will be fuel short with the F414. In any case the pure delta, with or without FBW is a dead end in Fighter wing plan forms. There is only so much you can do with it. Putting a more powerful engine to overcome sins of past and present inadequate design supervision will result in a weight spiral and give us a barn door and that too after uncontrolled delay. The LCA F414 will be a great help to those who are looking for a big well funded project with no time lines and no accountability.
I think if we just focus on the weight reduction and we will get a useful enough warplane. After that only minor tweaks – may be the wing tweak should be done. We could, after the first two hundred LCAs, talk in terms of a dedicated Ground attack fighter with a MiG 27 style "Utkanos", 30 mm Gast (I think the Russians have one) and some armour up to STANAG 2 level to reduce vulnerability to low cost AAA defenses (SA, LMG, MMG etc.). Warfare finally boils down to economics and losing a warplane to a F16 is perhaps acceptable but losing it to a ten shilling "jezzail" rankles!
ISRO and ADA – a case study
When INCOSPAR –later ISRO -was set up, the "Essential Critical Technologies" for interplanetary flight were well known. The Guiding lights of the ISRO programme, with the humility of the truly wise ignored Critical Technologies and set about with humble programmes for people building – Range safety procedures, launch procedures, simple instrumentations, small programmes where failures trained people to take carefully calculated risks. The first ISRO rocket went up to 42000 feet launched from what looked like a footstool and some ironmongery. The Mentors of the programme did not shy away from risks and failures and kept a low profile. There was never any desire to "show" any one anything. In thirty years i.e. by the early Nineties, ISRO had exceeded its original mandate handsomely The recent Mangalyan has shown not only the skills but also any uniquely independent Indian approach, priorities and philosophy to spaceflight. ISRO is a world leader in low cost space flight and a triumph of Indian abilities.
The bureaucracy that created ADA had the mandate to create another ISRO. They could have. They could have created a thought leader. What they did was a paradox- a dependant rival- made worse by a monopoly. This was repeated with the GTRE. It is not surprising that the Tejas programme is just where the Kaveri is. Almost there but, like the frog in Xeno's paradox, it will never get there. Indignation is one thing but is there anyone on the programme who can give a credible date by which the aircraft will be OK?
Study the real causes of delay
Much is made of the effect of sanctions and funding in delaying the project but were these only causes for unacceptable delays? There must be an investigation on the effects of indecision and perhaps unprofessional decisions where the progress of the project suffered. How much time was wasted in removing leaders who dared to think independently? The premature roll out is alleged to have set back the project by twenty months as reportedly, the whole thing had to be re done. How much time was spent between the prototype being ready and the decision to fly the first sortie? These three alone may have contributed six years in direct delays. How much time is spent in ensuring "safety" to ensure a "crash free" development programme? Should resources have been allocated, for example, to the development of a turbo starter when there was allegedly a resources crunch that was holding up the main project? The India wide network of supporting Institutions for the LCA programme certainly created a vote bank that would support to the hilt the project, its reviews and the requests for funds. We should examine what was the cost and effectiveness of the concept in terms of time required to review and supervise projects at distant stations? What was the mechanics of the remarkably indulgent Project reviews at the high levels that made a mockery of accountability? These are significant questions because unless these are analyzed and lessons absorbed any future programme such as the LCA 414 and the AMCA will go the same way.
We are almost there but will we?
To summarize:
1. Like the Kaveri, The LCA requires not more development but refinement. Lack of leadership in design both overall and detail has been a conspicuous, visible,continuing weakness.
2. The product, in terms of the letter of the law, has failed to replace the MiG-21.
3. It can be however be a good clear weather strike aircraft which is what every AF needs in large numbers.
4. To achieve 3 above the structural weight needs to be brought down. If still wanting, review some of the "occasional use" equipment in the specs. And throw them out!
5. We must snap out of the small annual production mind set. This will result in a HF 24 replay.
6. In absence of having anything better, get that HJT 36 development team back. Yes they made mistakes but they made them fast.
7. This team should work on: improving the production rate to 60 per year and to build all the aircraft ordered -warts and all- by 2017. No more pussy footing about further improvements because improvements are endless.
8. Stop thinking about the LCA F414. The pure delta, with or without FBW, is a dead end in fighter design. Better think of using the basic fuselage with a conventional shoulder wing and tail, a la Gnat. Conventional wings are more "tweakable" and in any case all the other "stuffing" will largely be the same. All this after skills have been demonstrated by getting the LCA Mk1 right. Show me!
9. Focus on the post natal period of LCA's IOC. The HF24 was often AOG'ed because of a lack of split pins! I am not being skittish when I say raise the first squadron at Yehlanka – provided there are sufficient 'married men's quarters'. House rent in Bangalore is exorbitant!
10. Just as GTRE has to be reorganized ADA has to be re-peopled if it is to be effective. Aircraft design is not all 'science". It still is an art. We always had the "Science "part but in setting up ADA the "Arts" part was clearly neglected.
Everyone loves a good drought
Public spending is always attractive for those who get to spend the money. It would appear that somewhere in the warrens of policy making there are people who want the LCA as a big fat project; they want it to continue indefinitely so they do not want it to succeed. The fact that we have the LCA flying is proof that at the engineer level there is no shortage of necessary skills. The problems of the LCA are simple and correctable. They must have been all known within the early days of flight testing. A reasonable sized group of young engineers suitably mentored could have solved them long ago. The question that must haunt the Defense Minister is that why were the problems allowed to fester for so long.
The ADA LCA: Beloved Aircraft or a Lemon | idrw.org
