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.
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:
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
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
|
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.
http://defenceforumindia.com/forum/indian-air-force/43717-ada-lca-tejas-iv-280.html#post1006849
ReplyDeletePlease visit the following page and answer all the uncomfortable questions!!!
why have you left out the all important Lift to drag ratio in his comparison?
ReplyDeleteWhy have you not added gripen, typhoon and rafale in the comparison list we could all have known the crucial facts?
while all other legacy fighters he listed in his comparison table are the past,
and
tejas, gripen, rafale, typhoon all Relaxed Static Stability , 4 channel all digital Fly by wire tech are the future with roughly similar specs , and have a vortex inducing canard or compound delta design for higher ITR flight regime important in this missile age, are left out.
Why?
very different from the specs of Gnat, JF-17 and Mig-21,
The half fuel empty weight TWR of tejas mk1 is 0.97, from where Mr. Das gets 0.87 is a mystery to me!!!!
SO "First the bad news:" and then the "And now the good news – if you are prepared to think differently!" are all same wrong diagnosis!!!!.
None other than the greek airforce chief himself has said that Mirage-2000 can not be beaten by F-16 on any day.because he says the higher Instantaneous turn rate(ITR) of Mirage -2000(which has ten percent lower thrust to weight ratio and ten percent lower wing area compared to its weight than tejas mk1!!!) allows the pilot to have a first look, lock and fire solutions on F-16. Ofcourse Instantaneous turn Rate is not included in that comparison table at all !!!!
tejas mk1 itself has far better thrust to weight ratio and far lower wing loading than updated Mirage-2000 itself!!! and as per IAf group captain and award winning test pilot Suneeth Krishna's claim tejas mk1 is "at least equal to updated mirage-2000". SO why should tejas mk1 have a hard time with F-16 A and JF-17 ?
So when a Mirage-2000 can win over F-16 A using this trait, how can you justify the absurd claim from Mr. Das that tejas mk1 is inferior to mig-21?
If we compare the aspect ratios of tejas with gripen, PAKFA , typhoon and F-22 , you can pretty much see that lower aspect ratios are no exception in these large compound delta with low wing loading RSS fly by wire tech?
In a pointed effort to confuse the reader you have only included older positive static stability higher wing loading lower wing area fighters like JF-17,F-16 and Mig-21 to make it look as if the lower aspect ratio of tejas mk1 is a big design mistake!!!!
The JF 17, F 16 are aircraft our gentlemen may have to face.
DeleteThe Gripen is a nice bird but of no interest to us.
BTW these have FBW also and not statiucally stable as you claim
The JF 17, F 16 are aircraft our gentlemen may have to face.
DeleteThe Gripen is a nice bird but of no interest to us.
BTW these have FBW also and not statiucally stable as you claim
Having FBW does not equal Relaxed Static Stability on all axes.
DeleteWe can put FBW even in older mig-21, that does not mean its airframe will conform to RSS- FBW agility of modern 4.5th gen RSS fly by wire fighters.
tejas like PAKFA is a compund delta . And naval tejas also has LEVCONS exactly like PAKFA.
ReplyDeleteSO PAKFA is also a waste of time by russians?
How do you compare the PAKFA which is a conventional layout with a pure Delta like the Tejas?
DeleteIf you do you are comparing oranges with apples -and obviously coming to the wrong conclusions.
The wing design of PAKFA and tejas are not very dissimilar . Also F-16 XL gave massive performance improvement over normal F-16 with the same kind of compound delta wing with no tail or canards added. It outperformed normal F-16 in all specs.
DeleteWhat is the Specific Fuel consumption of GE-414?
ReplyDeletetejas mk1 has lower empty weight than Gripen C.
tejas mk2 will surely have lower empty weight than gripen E(last heard its empty weight has crossed 8 tons).
So what is wrong with empty weight of tejas?
tejas has ,
1. Lower Empty Weight,
2. higher half fuel TWR,
3. Lower wing loading,
than gripen for all corresponding versions, So do you think gripen too is riddled with design mistakes?
The vortex generation job of gripen's canard is done by lower swept leading edge angle of tejas wing (near the wing root) with no additional drag and weight penalty.
So in no way you can call tejas a plain delta wing fighter meeting a dead end.
ADA has officially stated that the vortex generation effort of compound delta tejas wing form offered no disadvantages over the canard delta wing form(which was tested by ADA in wing tunnel) considering the additional weight and drag penalties it imposed.
IAF group captain and Award Winning test pilot Suneeth krishna has said that tejas mk1 is "atleast equal to upgraded IAF mirage-2000".
ReplyDeleteSo why you find it below Mig-21 level?
Equal with respect to what capabilities?
DeleteThe pilot has flown both Mirage-2000 and tejas mk1 extensively. So no use doubting his claims.
DeleteAlso NTSE chief Riaz Khokar has also said the same. tejas mk1 exceeds mirage-2000 in all key respects. And IAF can safely induct in hundreds to cost effectively replace the fast retiring Mig-21 fleet.
Both men knwe pretty much what they have to know to make these comments. And none of the tejas mk1 detractors have ever countered the comments of the above two men with any technical detail.
tejas is equal to 45 million per dollar plane upgraded mirage-2000 is Suneeth Krishna's original statement.
Delete1.Even if you spend hundred million dollars pre plane the radar of mirage-2000 will be smaller than tejas mk1.
2.the thrust to weight ratio of upgraded mirage-2000 will be lower than tejas mk1.
3.The wing loading (fighter weight in KG/ wing area in sq meters) of upgraded mirage-2000 will be higher than tejas mk1.
4.The frontal clean config RCS of upgraded mirage-2000 will be 3 times higher than tejas mk1, meaning mirage-2000 can be detected by enemy radar much farther away than tejas.
5.The longest range BVR missile to be fired by mirage-2000 will have way lesser range than the proposed Astra for tejas mk1.
6.Both the Instantaneous turn Rate and Sustained Turn rate of 45 million dollar per plane upgraded mirage-2000 will be lower than the 26 million dollar per plane tejas.
7.The 45 million dollar per plane upgraded Mirage-2000 still wont be able to fire the deadly visually cued R-73 E HMDS enabled 90 deg high off bore missile, which was fired by 26 million dollar per plane tejas eons ago.
8. the 45 million dollar per plane upgraded Mirage-2000 still wont have an equal to DRFM based state of the art EW suit of tejas mk1.
SO on all 8 counts the mirage-2000 will fall below tejas mk1.
The minister of state for defence Inderjit himself has stated that compared to western RSS fly by wire fighter development time frame of 15 years tejas mk1 whose funding for two TDs released only in 1994 is not very late at all.
ReplyDeleteis the minister right or Wrong?
I have reason to believe that the Honourable Minister is not quite a aviation man
DeleteIt is better that way. Every one who buys a ferrai need not be an auto mobile engineering Genius.
DeleteAnd IAF chief Aroop Raha himself has said that We have no doubts about tejas's capability.
What do you mean by good clear weather striker?
ReplyDeletetejas has proved itself in Leh, got all weather clearance and wake penetration certificate.
Don't you know that?
Yes I knew that.
DeleteNow how does that contradict with what I said?
The following is the description of Tejas ASR by MSD Woolen -" The monograph was brought out at Aero India 1998. The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec."
DeleteAs per the link below,
http://tejas.gov.in/featured_articles/air_marshal_msd_wollen/page02.html
So now despite tejas empty weight going up to 6500 Kg , it has cleared cold weather trials at leh by taking off with specified weapon load.
note the original MTOW for 5.5 ton empty weight tejas was just 12. 5 tons. Now 6.5 ton empty weight tejas lifts 13.25 tons as MTOW.
if the wing design due to lower aspect ratio is so draggy as you suggested how could tejas take off with 13.25 tons(0.75 tons more than the original MTOW)?
Also how could 6.5 ton empty weight tejas clear leh trials with the specs specified for 5.5 ton fighter?
because if there is such insurmountable drag problem (due a faulty wing design as you suggested) a one ton extra empty weight tejas can not lift 13. 5 tons as MTOW.
What is your explanation for that?
The original take off clean for tejas in 1998 was 8.5 tons. now it is 9.5 tons. original MTOW for tejas was 12.5 tons. now it lifts 13.5 tons.
DeleteAlso it completed a vertical loop in aeroindia 2013 within 20 -21 seconds(turn rate of 18 deg per sec , ASR specifies 17 deg per sec), even though it was overweight by an extra ton and had close to 400 Kg extra telemetry and air data sensor equipment on board.
At aeroindia 2013 it had an AOA limit of 20 deg, g limit of 6G. Now AOA has crossed 26 deg and G limit may end up 8 plus according to reports in papers.
if the wing design was so draggy how could it be possible for tejas to complete the loop in 20 seconds?
ofcourse for the horizontal loop it took close to 24 seconds.
Can JF-17 and mig-21 complete the vertical loop in 20 seconds?
DeleteAfter the crash of its first prototype gripen under normal landing condition SAAB abandoned its own Fly by wire effort and rushed to US company to do it.
ReplyDeletebut after repeated sanctions ADA has demonstrated 2500 crash free landing, take offs, AOA expansion upto 26 deg all weather and wake penetration clearance by developing and validating the fly by wire software and control laws using Iorn Bird test facility in HAl, which won wholesome praise from current IAf chief Aroop raha himself.
So a couple of crashes are needed to validate fly by wire perhaps?
I would rather have a few crashes than delay ten years on teh project.
DeleteBTW The total population of Sweden is less than Bombay's.
They may not have the human resources for everything.
If you think that a couple of crashes are needed to validate fly by wire do p-lease write to NFTC .They might oblige.
With meagre funding crash of prototypes will send the program to the gallows. And with wildly enthusiastic critics plonking a tombstone above the project citing series of crashes prove its design faulty.
DeleteThis is a lie to cover the real causes of delay which was incompetence for the given job.
DeleteIf the Indian Nation was so stupid then ISRO would have been given over to the property developers!
http://idrw.org/archives/59988#more-59988
Deletehttp://idrw.org/archives/59988
It is not a lie.Finally an empowered educated Defence minister names the true reasons for delays in critical projects, i.e changing the specs at repeatedly.,which resulted in delays in crucial projects.
http://www.thehindu.com/todays-paper/tp-national/the-case-to-support-the-indigenous-lca-programme/article1216752.ece
Delete“Go-ahead”
After consideration, including by special committees, the Indian Air Force and the government gave the real operational go-ahead only in late-1993. Even that “go-ahead” covered the development of only two Technology Demonstrator Aircraft (TDA) without weaponisation. The funding approved was only of Rs.2,000 crore — half the amount requested for full-scale development. The first TDA flew in 2001, eight years from the real operational ‘go’ date, despite much additional R&D work that had to be undertaken due to the U.S. sanctions imposed in 1998.
Comments appeared in the media in 2001 quoting IAF sources to the effect that what the ADA had achieved was just a flying machine that was yet to be weaponised. Considering the nature and scope of the approval accorded in 1993, what else was to be expected? Using the money sanctioned for two TDAs, the ADA built four. Full-scale development, for which another Rs.2,000-plus crore was finally sanctioned, thus started only in late-2001. Some 1,200 hours of flight testing was to be undertaken to secure Initial Operational Clearance (IOC) from the IAF.
At that point, apart from the weaponisation requirements the project had to undergo extensive redesign to accommodate an air-to-air missile chosen by the IAF, which was considerably heavier and longer than what had been specified till 2000. The IAF had again changed its mind. This necessitated the complete redesign of the wing structure, using only composite materials in order to keep the weight within limits. The period of this redesign was also utilised to upgrade the avionics, to a completely open architecture.
Consequently, in “generational terms” the LCA is a fourth generation-plus aircraft with full networking capabilities. This made it more than comparable to anything the IAF had, and possibly would have, even after it acquires the 126 Multi-Role Combat Aircraft (MRCA) now on tender, with first deliveries due eight years hence.
From the same THE HINDU article,
DeleteOn the engine
It is true that the Kaveri engine for the LCA that the Gas Turbine Research Establishment (GTRE) of the DRDO has been developing for 12 years has not yet met its technical performance targets and requires redevelopment. So far the GE 404 engine from the U.S., which powers the F-16 fighter-bomber, has been used to power the LCA. The problems the GTRE has with the Kaveri are not unusual in a complex fighter aircraft engine project being undertaken for the first time. Moreover, the financial sanction of about Rs.320 crore given for engine development was possibly only to cover the Project Definition Phase and some high-risk technology development effort. We do not know of a first-of-type high-technology fighter aircraft engine being developed anywhere in less than a multi-billion dollar programme and a 20-year-plus development cycle. Even Snecma, the sole fighter aircraft engine manufacturer in France, despite decades of experience in developing and manufacturing engines for Mirage III, V and F-1, took about a decade and $2.2 billion to develop the M-88 engine for the Mirage 2000. The development of the Kaveri is unlikely to cross $1 billion.
The LCA with a GE 404 engine has done 800-plus hours of flight-testing. Even with that engine the performance has been not only vastly superior to that of even the recently upgraded MiG 21 BIS (the IAF is operating almost 400 of the series), but it has shown itself to be comparable in many critical parameters to the Mirage 2000. Modifications to the aircraft structure are under way to reduce weight and improve engine performance. When the GTRE’s joint venture with a leading foreign engine manufacturer for further development is completed in the next four years, the Kaveri will be brought up to a performance level, superior to the GE 404. Fitted with it, the LCA will be truly comparable to the Mirage 2000 and in many respects even superior. And all this in an aircraft much lighter than the Mirage 2000.
from the same Raman Puri, Ashok partha sarathy article,
DeleteSuperior
As for network-centric capability, which intrinsically needs indigenous systems for secrecy, security and inter-operability, it is superior in the LCA compared to any aircraft in the IAF’s inventory.
So it is a fallacy to think that we can continue the importing spree and still have such network-centric capability.
As recently as in 2005, the IAF’s requirement for 126 new aircraft was only for an upgraded Mirage 2000. At Rs.120 crore to Rs.140 crore a plane, compared to at least double that amount for any of the aircraft types now bidding for the 126 MRCA, is not the LCA a highly cost-effective fighter for volume induction into the IAF?
As for development costs, the LCA has remained well within the sanctioned $1.2 billion — which is about the lowest anywhere. Time overrun in the strict sense is only by a year or two, despite the sanctions. A first-of-type aircraft of this degree of complexity has not been developed anywhere in the West or in Russia in less than two to three decades.
The F16 series that was inducted into the U.S. Air Force in 1975 is today at Mark 60. That is how aircraft of this level of complexity are improved after induction. That this imperative applies even more to the LCA has to be recognised.
It is for the Prime Minister and the Defence Minister to ensure that this effort is not belittled or scuttled, and that the LCA programme is given all-out support — as successive Prime Ministers have ensured for our atomic energy and space programmes.
(Ashok Parthasarathi was Science Adviser to Prime Minister Indira Gandhi. Vice- Admiral (retired) Raman Puri was Chief of Integrated Defence Staff to the Chairman, Committee of Service Chiefs, remaining closely involved with the inter-service weapons acquisition process from October 2003 to February 2006).
DO you know the basic fact that gripen c has higher empty weight and lower internal fuel capacity than tejas mk1?
ReplyDeleteLCA mk 1 and Gripen C are Oranges and apples.
DeleteThat's why you have concluded as you have.
No. It is your view. Never proved anywhere.Advertising total weight carrying capacity of a fighter's pylons as max weapon load is not a fair way to represent the weapon weight of fighter. If that norms are to be used even ADA can say tejas can carry 5 tons.
DeleteISRO too did not complete development of GSLV with 5 ton launching weight as achieved by Ariane , china and US.
ReplyDeleteSo shall we fire all the top brass of ISRO?
As Cecil B De Mille said "Include me out"
Deletefacts are fact ISRO's cryogenic tech too is a long drawn out project just bearing fruit. If we used a knife and fork to play with the lead project team no one knows where it would have gone.
DeleteAlso present govt doesn't beleive the top ADA - tejas management was such incompetent bunch of buffoons. Contrary to that key men involved in the projects were all given extension.
GE-414 is the navys solution to compensate for increased landing gear weight for career landing requirement . And IAF also asked it to increase the Turn rates primarily and to improve the TWR.
ReplyDeleteWho told you GE-414 was for increased range?
Who told you that?
DeleteJust who goole who funded the Tejas project first.
DeleteIt was told by none other than LCA Navy Project Director Commodore CD Balaji, in the last aeroindia 2013 as a cure for the extra weight of naval LCA's higher weight landing gear, which prevented tejas mk1 from carrying meaningful payload.
. It was widely reported in the news for a couple of years.
Even now the guy is so confident of Naval tejas mk2."
LCA Navy Mk-2 will not be delayed," said Balaji with a lot of confidence. "We are close to freezing its design, which has been simplified. The new design would be easy to implement."
For ramping up production HAL is asking for an additional sum of 1600 cr to increase the capacity of prodoction line. What has it got do with HJT team?
ReplyDeleteManagement
DeleteMoney is not everything
Management
DeleteMoney is not everything
Without money what will the management do?
DeleteIf management is everything why was there a condition put in MMRCA tender that with in three months of signing of MMRCA deal GOI has to pay close to 18000 crores to the foreign firm?
They have good management, So why do they need the money urgently?
The one who wanted those extra 1600 crores for doubling tejas production capability was HAL chief.
The new engine doesn't need new ducts.
ReplyDeletehaven't you read ADA DG Aero tamilMani's comment that present tejas airintake can cater to airflow requirements of GE-414?
http://www.saabgroup.com/Global/Documents%20and%20Images/Air/Gripen/Gripen%20product%20sheet/Gripen_Dimensions.pdf This is enought to expose your lies about Gripen empty weight claims
ReplyDeleteDr./Mr. Shakthivel
ReplyDeleteI am puzzled by your assumptions and request you pl. read my paper once again in acalmer frame of mind.
Prodyut
Sir,
DeleteThe claims of Suneeth krishna and Riaz Khokar won't change whatever be the state of the mind of the reader.
Also tejas completing a vertical loop in aeroindia 2013 itself with the restricted then flight envelope of 6G and 20 deg AOA is also not going to change with respect to the state of the mind of the reader.
And gripen C having more empty weight and lesser powerful engine will also remain a constant.
So the bit higher max take off weight of gripen c over tejas mk1 is meaning less as it has a bit higher empty weight over tejas mk1.
Also most of the specs of gripen C was given to ISDA conditions where ambient temp is far lower to the conditions over which tejas specs are give. You yourself has written that 10 deg higher ambient temp of indian atmosphere will sap close to ten percent of engine thrust and twelve percent of wing lift.
So we can verify gripen C's specs when it performs in those higher ambient conditions to make a fair comparison with tejas mk1.
With gripen E empty weight crossing 8 tons, tejas mk2 too wont be worse off coresponding to gripen E's performance.
Also tejas completing a vertical loop in aeroindia 2013 itself , within 20seconds ,with the restricted then flight envelope of 6G and 20 deg AOA is also not going to change with respect to the state of the mind of the reader.
ReplyDeleteWhat ever be the state of the mind of the reader, these things about tejas won't change,
ReplyDelete1. 4 channel relaxed static stability fly by wire airframe,
2. tail less delta with low wing loading, and high thrust weight ratio to excel in high altitude himalayan theater where taking off with meaningful load within the specified runway length depends on these factors
3. All glass cockpit, and avionics that minimizes pilot loads and designed with active inputs from test pilots through out the flight test regime,
4. RCS reduction mechanism,
5.latest engine tech(present engine on rafale is more than two decades old in thrust levels)
6.Ability to fire 120 Km range BVR missiles with a decent sized radar,
7. A fly by wire airframe with wake penetration and all weather clearance,
8. Ability to fire the deadly HMDS enabled visually cued R-73 E WVR missile? (described as one of the best in the world by Air marshal and former HAL chairman MSD Woolen. Even tejas mk1 has it now but it is proposed to be added to rafale later at extra cost to ourself).
9. Higher percentage of weight reducing , radar refection minimizing composites that enable high thrust to weight ratio for a given airframe mass?
10.The combination of high TWR and low wingloading RSS delta airframe which enables agile turns to evade BVR missiles and get a first shoot ability with Visually cued R-73 E like WVR missiles in close combat, which is a must have option in modern 4.5th gen airframes
11.Ability to carry a mini brahmos like cruise missile weighing close to 1.5 tons on its center line pylon.
12.OBORG for extended refuelled flying in high altitude with the aid of refuelling,
13.A 1.8 mach top speed in its service ceiling with 9 G limits.
14. A must have less than 1 sq meter clean config which enables to drop away from long range radars once heavy external weapons and fuel tanks are released.
15. A good fuel sipping engine that is reliable and modern for some time to come.
16.Ability to fire ramjets 120 Km range missiles like meteor with an ASEA radar that can track long enough,
17. Modular in design and Ability to be upgraded in batches as and when new techs like better sensor fusion, better ASEA radar and better IRST devices arrive.
18, An option to upgrade to a higher thrust engine,
19. A flow separation postponing arrangement like ,
canard or levcon or cranked delta which generates vortex over the top of wing leading edge in high angle of attacks to enables air suction over the top of the smoothly blended upper wing body fuselage,
there by delaying the onset of stall and enabling the wing to reach designed max lift coefficient of the wing which is not present in older delta platforms like mirage-2000.
Also these lift enhancing mechanism along with flawless Relaxed static stability 4 channel fly by wire tech that allows the hassle and easy flying at sea level which is not the case with earlier tailless deltas which did not have the above mentioned techs .
That wont be present in tejas mk2 and( mostly present in tejas mk1 with a few exceptions like G limits, OBORGs and topspeeds and a bit lower TWR)?
Effective combat range with effective weapon load will depend upon the criteria called fuel fraction, i.e weight of internal fuel/empty operational weight of the fighter.
ReplyDeleteIn this area even tejas mk1 better than gripen C.
Then a question arises why range of tejas was often quoted less, it may be due to the reason that new super sonic center line fuel tank was not validated till IOC-2, Even without that The press information beruau release clearly stated that the combat range of tejas is 500 Km. It means a combat range in excess of 1000 Km in a low penetration fuel consuming flight into enemy territory, with extra fuel allocation for take off, a few minutes of high fuel consuming close combat and high fuel consuming After burner thrust .
But other fighter makers give misleading combat range figures with minimum weapon config and high altitude(less fuel consuming flight path) with no allocation for close combat and AB thrust and low penetration mode.
Roughly the fuel fraction above will give us effective combat utilization of the fighter.
Su-30MK: 34.9%（Empty weight: 17,700 kg，Internal fuel: 9,500 kg）
Rafale: 31.4% ~ 33.6%（Empty weight: 9,500 ~ 10,220 kg，Internal fuel: 4,680 ~ 4,800 kg）
JAS-39NG: 30.6%（Empty weight: 7,100 kg，Internal fuel: 3,130 kg）
MIG-35: 28.6%（Empty weight: 12,000 kg，Internal fuel: 4,800 kg）
Tejas: 27.0%（Empty weight: 6,500 kg，Internal fuel: 2,400 kg）
JF-17: 26.3%（Empty weight: 6,450 kg，Internal fuel: 2,300 kg）
JAS-39C: 25.0%（Empty weight: 6,800 kg，Internal fuel: 2,268 kg）
This is a fair comparison of fuel fractions with just internal fuel , and the same percentage will more or less reflect with external fuels also,
So Tejas mk-1(which still has 400 KG of flight test equipment on board, removal of them will lead to even better fuel fraction) itself has much better fuel fractions than grippen C/D with more TW ratio and lower wing loading,
Tejas mk-2 will easily compare to RAFALE which has just 4 percent more in fuel fractions than Tejas mk-1.
So in indian conditions there won’t be no issues with range of tejas mk-1 or mk-2 in useful combat configuration if we take into account that four tejas can be operated for one RAFALE if we include total lifecycle costs and upgrade costs,
So there is no way Tejas can be faulted on weapon load or range. A full read of the link above will show how fighter makers abroad indulge in word play when it comes to range and load figures!!! , to fool the people.
There is a small mistake in the sentence-,"The press information beruau release clearly stated that the combat range of tejas is 500 Km."
ReplyDeleteCorrect version is,"The press information beruau release clearly stated that the combat radius of tejas is 500 Km."
http://www.f-16.net/forum/viewtopic.php?t=1872
ReplyDelete"As far as the M2000 vs F-16 comparison is concerned, I should add something totally practical which comes from daily usage of both types in HAF. What I want to say is generally that when a HAF M2000 wants to engage a Viper, it leads the Viper at low altitude where the M2000 connot be beaten in any way.
I haven't seen yet any aircraft-apart from Su-27 family,which is, for me, the best aircraft ever built-that can achieve "Kill Hour" on a M2000 below 6-7,000 ft no matter the aspect between them. Ok? I have nothing else to add,as Fantasma337 -ask him about F-4E, I think no one else knows more about this aircraft- and the other Greek friends covered me and gave you a very clear picture about the M2000.
PS: I should mention that this is not a thread talking about HAF and TuAF or Greeks' and Turks' politics.
I served in an M2K fighter squadron in HAF. We analyzed tactics and combat scores against HAF F-16 squadrons all the time.
The M2Ks higher INSTANTANEOUS turn rate gives it an advantage during the first pass. The F-16 cannot outturn the Mirage. It has to climb in hopes of avoiding the lock. A good M2K pilot will end it right there (the Magic 2 is a better IR weapon than the AIM-9L/M).
A rookie in the M2K, however, will probably lose the F-16's climb. The more powerful viper will escape and will then gain the advantage because of 1) Altitude 2) Higher SUSTAINABLE turn rate.
As for turn rates, altitude differences are purely theoretical and in practice make no difference EXCEPT for sea level manuevers where the more powerful Viper starts gaining the advantage.
Would you agree with the statement that F-16 is a better choice for multi role missions than Mirage 2000 ?
Absolutely. The M2K is a multi-role fighter also, but its performance varies greatly among roles - whereas the Viper performs almost all missions at a very satisfactory level.
HAF M2Ks are specialized. 331's (where I served) primary role is now TASMO (naval strike with AM-39 Exocet) and 332's primary role will become Deep Strike (with SCALP EG). CAP & Air Supremacy are their secondary roles.
The F-16 sqdns OTOH undertake a number of roles such as SEAD, CAP, CAS, and numerous specialized strike missions (enemy AFBs, enemy C&C centers etc). The Viper is a much more volatile weapons system".
http://www.f-16.net/forum/viewtopic.php?f=30&t=1872&sid=9792b3c0fa2ea774a3b775e8d457200d&start=30
"Read an article in the magazine "Illustrated Aircraft" from March 2005 where a HAF MIRA 330 squadron commander states the following:
"I'm very satisfied with the F-16 - in fact, I love it. In particular I love the Block 30."
He also states about the Mirage 2000 used mainly for Air to Air:
"It's an effective fighter, which the f-16 can't beat in a dogfight."
He ends by saying:
"The F-16 is much better multi-roll combat jet... it really is the complete package..."
To me this captures it in a nutshell."
Even though Mirage-2000 had far lower thrust to weight ratio than F-16, the large wing are low wing loading wing design of Mirage-2000 always enabled Mirage-2000 to have a fast turn and get a first lock and shoot solution for its WVR missiles in combat. Mirage-2000 does not have a visually cued HMDS enabled HOBS missile like R73. But tejas has this extra advantage also.
ReplyDeleteThere is no need for canards on tejas mk1 or nk2 as Air marshal Matheswaran says in his course correction for LCA progran article.
Tejas has a far more power ful and bigger wing attached control surfaces than gripen to give the required turning effect.
With canards gripen has more empty weight and the same fly by wire usable AOA of Tejas mk1. Lack of canards have not resulted in lower fly by wire usable AOA for tejas mk1 over gripen C.
Canards is a vortex enabling control surface. WIthout that tejas mk1 reaches the same AOA means there is no need for this extra weight and drag inducing surface.Compound delta in tejas takes care of vortex based lift augmentation , the same job done by canards of gripen.
Tejas mk2 with more power ful engine and further composite percentage will address the weight problem. The gripen E empty weight has beyond 8 tons. In contrast DRDO aero DG has said that ADA was successful in eliminating 350 KG of weight from tejas mk1 for Tejas mk2. Tejas mk1 has a 200 KG ballast behind the nose for CG correction . This too will be done away in tejas mk2 redesign.
Unlike the addition of more drag inducing fairing s for gripen E , tejas mk2 will have a 5 percent lesser drag even with increased wing and fuselage area due to the 0.5 meter fuselage addition reducing wave drag with better fineness ratio.
SO I don't know why people are asking for the inclusion of canards at this latter stage.
It is interesting to note that with 20 deg AOA and 6G li8mitatio Tejas did a 360 deg vertical turn within 20 seconds giving it a vertical turn rate of close to 18 deg. In horizontal turn it took more than 24 seconds with those limits. Mow according to tamil Mani DRDO aero DG those limits will reach close to 28 deg AOA and 8 plus Gs.
We have to see what kind of STR and ITR will it give before commenting on imaginary shortfalls in climb rate and STR.
Even though having lower TWR Mirage-200 can have higher instananeous turn rate compared to F-16 with its class leading low wing loading and analogue relaxed Static Stability air frame.
ReplyDeletetejas has ten percent more TWR(half fuel load and two WVR missiles only only) than Mirage-2000(half fuel load with two WVR missiles only ) and has a substantially larger wing loading(far lower than Mirage-2000).
Add to that Tejas has digital Fly by wire system .
So if Mirage-2000 in the words of former greek airforce dhief can enjoy some advantage over F-16 then there is no need for tejas mk1 to fear a f-16 in close combat , simply because it exceeds mirage-2000 in all the three crucial parameters mentioned above,]
1. wing loading,
2. TWR(half fuel load,with two WVR missiles only).
3.Digital fly by wire system,
And lastly coming to the so called drag issue.
As per Whitcomb's area ruling for a lower super sonic drag the cross ection of the fighter should increase gradually from nose to mid fuselage and then decrease gradually.
THE CEMILAC report which mentioned the sudden increase in cross section from on the fuselage from 4 meters to 5 meters (lengthwise)as a reason fro tejas mk1 failing to cross supersonic speeds in sea level has been misunderstood by many people as the reason being lower specs of tejas mk1.
Reality is a bit more complex. This extra drag kicks in only in super sonic flight, not in sub sonic corner velocity flight regime under which close combat dog fights take place.
All SUstained turn rates, (STR) and Instantaneous Turn rates for all fighters are not given for supersonic speeds.
They are all given for Subsonic Corner velocity flight regime , i.e below the super sonic speeds.
SO in those speeds there is no extra drag.
But even this issue has been sorted out some how with tejas mk1 certified for super sonic speeds in all altitudes.
So this issue is a bit more complex .
Professor, Your calculation regarding T/W for most aircraft are grossly wrong. you have calculated LCA on the lower side and other aircraft on the higher side. I suggest that you pls re-check your data and calculations. LCA with 6500kgs as empty weight and 9000 kgs as loaded weight has a T/W of 0.6(dry) and 1.0 (A/B). Though I do agree to just few of your points but most are bullshit to say it politely. I am a retd fighter pilot myself and very well understand what you have written here. If calculate wrong, you will arrive at wrong calculations. I do agree to your point that LCA wing shud have been reversed i.e it shud have more sweep in front and less sweep at rear and that engine shud have a bit more dry thrust. LCA does not need more of A/B thrust, it needs more of dry thrust.
ReplyDeleteADA has again gone wrong by selecting F414 engine which will give adry thrust of just 62.5KN. EJ-230 wud have done wonders to LCA with its dry thrust of 72KN.
ReplyDeleteLCA weight is 6500 kgkg with pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 kg, =7385 Kg+ 1250 kg of internal fuel(half fuel weight)=8635 Kg
So TWR at half fuel weight with pylons and two WVr missiles is =0.97
This combined with the lowest possible wing loading of 242 Kg per square meter give tejas a very good combo of wing loading and TWR.
other fighters like f-16 may have more TWR, but they have higher wing loading. it means the area from which they generate lift for sudden turns is lesser for them compared to tejas mk1.
the reason tejas has lower TWR than F-16 is it has to support much larger wing area than f-16.
SO when we take these two factors into combo we can see the effectiveness. because mirage-2000 with much lower TWR than tejas and much higher wing loading than tejas has been favored by none other than greek airforce chief for even close combat , because the higher Instantaneous turn rate and higher G on set rate given by the combo of low wing loading and high TWR gives the first shoot advantage for mirage-2000 in dog fight over F-16.
With tejas mk1 comfortably ahead of mirage-2000 in both the specs there should be no worry for tejas at all in close combat with even the famed f-16s of PAF.
So how the prof rates tejas mk1 between Gnat and Mig-21 is a mystery to me!!!
I have not even included terms like high alpha and Relaxed Static Stability air frames here. because the RSS airframe of tejas mk1 is said to give negative stability to tejas mk1 through out its flight envelope according to a research paper , (even in super sonic flight is the assumption).
This factor also adds to better agility of tejas.
regarding mig-21s, Please give us the break up as I have stated above for a real comparison.
All the so called drag for not followign Whitcomb's rule more rigidly comes into play only in super sonic flight regime, not in subsonic flight regime of WVR combat speeds.
ReplyDeleteSo no drag issues here also.
Also in an F-16 vs F-16 XL comparison the G on set rate for F-16 XL was far more. In fact the low wing loading f-16 XL(a tail less , canard less compound delta like tejas) beat the high wing loading normal F-16 in all crucial combat specs and was considered an evolution over normal f-16 design.tejas was modelled on F-16 Xl.
ReplyDeleteM/s Shakthivel and Pathak
ReplyDeleteYou are obviously not reading what I have written and I find it tiresome to point out errors of your understanding.
I have taken clean full fuel weight ( 2400 kilos) BECAUSE IN ALL THE COMPARISONS IT WAS NOT POSSIBLE TO GET THE INTERNAL FUEL CAPACITY. THIS DOES NOT CHANGE THE FIGURES OF COMPARISON because identical parameters were used in all cases.
OBVIOUSLY YOU HAVE NOT READ OR UNDERSTOOD.
I am refraining from answering your other questions because I have failde to understand what you are driving at. Perhaps if we meet sometime.
BTW Whitcomb's area rule will change with the speed you are designing for. Many modern designers will ignore it e.g. Lee Begin did in the change from Northrop F5 E to F20 but it is too long to discuss here!
MR. Pathak in which course did you graduate out ?
I am a retd naval fighter pilot. I am ex NDA and I am BSc. I did my flying with 141 PC.
DeleteSIr , if you fail to understand my queries , I have nothing to gain by reading the article again.
DeleteWHat I said was compare tejas with its peer like mirage-2000, gripen and other euro canards if we are interested in knowing the design similarities or mis match.
All the fighters you used in comparison table share nothing with 4+ gen RSS fly by wire compound delta like tejas,
low wing loading on tejas was proposed with the primary aim of high ITR not for high or low stall speeds(it is another matter no one knows these specs of tejas)
LEVCONS are no fixes !!! Even in 2001 article on tejas by none other than Air Marshal MSD Woolen LEVCONs for naval tejas was proposed for carrier landing requirements.
e without going into specs like a combo of TWR and low wing loading advantage making suggestion on which fighter wing design is best is a suicidal job. Does this mean the russians who designed PAKFA hich has the samelower swept wing root didn't know of these "facts"?
If we accept the suggestion of reversing the wing sweep as proposed by Mr Pathak, who will do the job of vortex generation which is presently done by lower swept wing leading edge root near fuselage. Why this "great design " idea of reversing the wing sweep is not followed by Russians in PAKFA ?
combat radius of tejas mk1 without certification of center line fuselage was given as 500 Km for hot indian climatic condition which saps 10 percent engine thrust and
12 percent wing lift for any other fighter. SO why the fuss?
What is the clean full fuel weight of Mig-21?
DeleteThere is a distinctive advantage of delta planforms in air combat compared to other planforms. And what matters most for ITR or STR is the CLmax and stall speed. Higher the CLmax, lower the stall speed, more is ITR & STR.
ReplyDeleteROT=Rate of turn T (*/sec)= 1091*tanbank/v & radius of turn=Rad of turn R (ft)=v^2/ 11.26 tanbank
Many a times we go wrong in benchmarking the agility of an ac with wingloading. many ac can have higher wingloading but a very low stall speed due to a combination of many aerodynamic factors like LERX, MAW etc. One of the biggest disadvantage of low wingloading is poor gust tolerance and if we have wing like LCA, it also means extremely poor CLmax so even with low wing loading, we end up having a high stall speed which defeats the very purpose of having low wing loading. there are ac like Mig-29/Su-27 also which produce a large amount of lift from the fuselage.
If we go by efficiency of a design, A wing-tail, unstable combo is best, canard-delta RSS is second best, a wing-tail, stable design is third best and last is tailless delta RSS/Stable. All combinations of canard-delta and tailless delta suffer from high landing speeds as they can't handle double slotted flaps at TE of the wing. While canards do provide higher CLmax but use of slats-double slotted flaps provide much lower landing speeds for the same airframe. It is for this reason that I have more faith in wing-tail combo compared to canard-delta or tailless design. If we use a wing-tail combo with TVC, we can have stability and unstability on demand and such a combination emerges as the most efficient, least risky simple to operate design.
LCA as a design is inefficient and it is for this reason that they are now applying fixes to it in the form of Levcons etc. The best is to just change the wing and instead of 50*-62.5* make it 62.5*-50* and add LERX. This will reduce the wing area to a more respectable 30sqm and also take the AR to 2.25 which is the ideal AR for high speed interceptors. This will also help increase the wing fuel load.
In its present shape, LCA is still a capable ac and comparing it with JF-17/Mig-21 etc is wrong. this ac even today can easily take on these ac in combat. In air combat, there is a way in which you use a delta planform. today we have HMDS and agility has lost most of its meaning with missiles like R-73 but even in guns only fight which is a true dogfight, LCA will outperform the ac which you have listed but the very big question is, where will you go to fight with just 2.4tons of fuel? you will use up 200kgs in start up taxi & T/O. You will need another 200Kgs for landing circuit+400 kgs as standard reserve. That leaves you with just 1600 kgs to go to the combat zone and return. Mig-21 uses about 2000ltrs/hr and that gives it a range of 750 kms and is a turbojet engine, LCA has a turbofan, so we can assume a range of about 1000kms but than we need fuel for combat also, so we are down to a combat radius which is very easily equal to just about that of Mig-21.
LCA Mk2 will not offer much of a respite, ADA must redesign the wing and increase the length to be 14.5m atleast. that will give it more fuel and better agility.
DeleteSIr If my memory is right you are Mr. Decklander with whom I had a very long argument ontejas in DFI. SO I don't want to take the same acrimonious route here,
Just a few queries
All the fighters you used in comparison table share nothing with 4+ gen RSS fly by wire compound delta like tejas,
low wing loading on tejas was proposed with the primary aim of high ITR not for high or low stall speeds(it is another matter no one knows these specs of tejas)
LEVCONS are no fixes !!! Even in 2001 article on tejas by none other than Air Marshal MSD Woolen LEVCONs for naval tejas was proposed for carrier landing requirements.
e without going into specs like a combo of TWR and low wing loading advantage making suggestion on which fighter wing design is best is a suicidal job. Does this mean the russians who designed PAKFA hich has the samelower swept wing root didn't know of these "facts"?
If we accept the suggestion of reversing the wing sweep as proposed by Mr Pathak, who will do the job of vortex generation which is presently done by lower swept wing leading edge root near fuselage. Why this "great design " idea of reversing the wing sweep is not followed by Russians in PAKFA ?
combat radius of tejas mk1 without certification of center line fuselage was given as 500 Km for hot indian climatic condition which saps 10 percent engine thrust and
12 percent wing lift for any other fighter. SO why the fuss?
combat radius of tejas mk1 without certification of center line fuselage was given as 500 Km for hot indian climatic condition which saps 10 percent engine thrust and
ReplyDelete12 percent wing lift for any other fighter. SO why the fuss?
There was a mistake in the comment above,
It is center line fuel tank and not center line fuselage as I have typed
Tejas mk1 has a comparable enough fuel fraction with other fighters and doesn't fall far short of Gripen C, so nothing basically wrong here.
ReplyDeleteIn BR I was surprised to find this comment -"All the so called drag for not following Whitcomb's rule more rigidly comes into play only in super sonic flight regime, not in subsonic flight regime of WVR combat speeds.So no drag issues here also." as face palm!!!
ReplyDeleteThe comment was from Indranil Roy,
What I meant was many people were using the
CEMILAC report which mentioned the not so gradual increase in cross section from 4 to 5 meter on fuselage length being the prime reason for the Tejas not achieving its design top super sonic speed at sea level(no brochure says tejas is super sonic at all levels)
as a diagnosis of general drag(which people allege ,ADA failed to notice during wind tunnel or computer modeling) which prevents Tejas from reaching its ASR specs on STR and G limit(which ASR is again no one knows, Tamil Mani Aero DG was last heard talking about 1994 ASR, i.e an ASR 5 years after design freeze).
What I wanted to point out was the general ITR and STR specs are not for supersonic speeds, but corner velocities below super sonic speeds.
In those speeds CEMILAC diagnosis does not hold water.
Good if some one from other forum, Indranil Roy himself, or Mr Das can explain this .
(no brochure says tejas is super sonic at all levels)
ReplyDeletetypo again ,
correct version is
,
(NOW brochure says tejas is super sonic at all levels)
regarding the statement of yours,
ReplyDelete"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."
https://www.google.co.in/search?q=gripen+wing+span&oq=gripen+wing+span&aqs=chrome..69i57.3557j0j8&sourceid=chrome&espvd=210&es_sm=93&ie=UTF-8
gripen wing span =8.41 meters,
https://www.google.co.in/search?q=tejas+wing+span&oq=tejas+wing+span&aqs=chrome..69i57.2807j0j8&sourceid=chrome&espvd=210&es_sm=93&ie=UTF-8
tejas wing span is 8.21 meters,
So everything seems to be proportional ,
If 14.1 meter gripen A has 8.41 meter wing span,(ratio--1.67)
the 13.2 meter long tejas has 8.20 meter wing span.(ratio -1.61)
nothing exceptionally amiss hers,
regarding your comments,
ReplyDeleteThe 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 2185 Kgs fro all other stuff,
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!
1.Does marut had the wing strength to fire R-73 E missile?
2.And what will be the additional weight of supporting excess volume of fuel than marut?
3.How much weight is needed to support much larger wing area of tejas compared to Marut?
4. how much weight is needed to support 13.5 tons MTOW and the stress it puts on airframe when in take off mode?
5. How much more weight is needed to support way higher touch down weight than that of MArut?
if you add them all it will come close to gripen C's empty weight , which supports 200 kg lesser fuel load than tejas and has 25 percent lower wing area than tejas.
Test mail
DeleteShakthivel
DeleteQ1.&2. Any underwing stores- missiles,engines ( as in Boeings) drop tanks actually help in reducing wing root bending moments and torsional stresses. Work it out! The Northrop F5 series used the tip missile launch rails to reduce torsional loads.
The drag loads in flight of a drop tank is higher than ,say a R73 and the shear loads at launch is much less. Ditto fuel. So your worry is easily answered.
Q3. The delta planform has along root chord and hence a great spar depth. IF anything sq.mts per sq.mt. teh LCA's wing should be much lighter than the HF 24s.
Q4 &5.The HF 24 MTOW would probably have been around 17 tons as it was designed for the B.Or.12. The puny thrust of the B.Or.3 limited it to around 13 tons MTOW
It is easy to show that a heavy airframe is not necessarily a strong airframe.
NOTE to other readers: It is not possible often to answer queries on time or even at all. These are all ideal for Viva Voce as in a class.
Shakthivel
DeleteQ1.&2. Any underwing stores- missiles,engines ( as in Boeings) drop tanks actually help in reducing wing root bending moments and torsional stresses. Work it out! The Northrop F5 series used the tip missile launch rails to reduce torsional loads.
The drag loads in flight of a drop tank is higher than ,say a R73 and the shear loads at launch is much less. Ditto fuel. So your worry is easily answered.
Q3. The delta planform has along root chord and hence a great spar depth. IF anything sq.mts per sq.mt. teh LCA's wing should be much lighter than the HF 24s.
Q4 &5.The HF 24 MTOW would probably have been around 17 tons as it was designed for the B.Or.12. The puny thrust of the B.Or.3 limited it to around 13 tons MTOW
It is easy to show that a heavy airframe is not necessarily a strong airframe.
NOTE to other readers: It is not possible often to answer queries on time or even at all. These are all ideal for Viva Voce as in a class.
Also you can add extra weight of much more powerful hydraulics that bulge out in fairings to support way bigger wing attached control surfaces of tejas mk1 .
ReplyDeleteAnyone listing to you and taking course correction sir
ReplyDelete