You should ask DAS , why he left out the all important Lift to drag ratio in his comparison?
If at all Das added gripen, typhoon and rafale in the comparison list we could all have known the crucial fact
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,
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!!!!
of course no one can ever accuse Mr. Das of even handedness or rationality, which I know very well from his past rants dumped as "expert analysis"!!! on unsuspecting readers!!!!!
SO "First the bad news:" and then the "And now the good news – if you are prepared to think differently!" are typical DAs bullshit as usual. Wrong data , wrong type of comparison with dino era fighters, and the same wrong Witch Doctor diagnosis!!!!.
Any number of Degrees and fellowships are never going to change the delusional contorted view far away from Reality which MR. Das wishes to project!!!!
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 Mr. Das only includes 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!!!!
There is no prize for guessing why this crooked fake article is now published, timed to coincide with aeroindia 2015. Just to confuse people!!!
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Please read Ails of Tejas previous Das write up on tejas, in the link below, to know the motives of Mr. DAs who is a regular contributor to IAF magazine-"Vayu" with the express purpose of printing out fake critiques on tejas with no facts to support those bogus claims,
You could as well have read my questions to prof Das refuting each and every point you have posted above in the comments column.
Which prof Das refused to answer.See in the following link,
Prof. Prodyut Das: The Ails of the LCA
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1.Just want to comment on your portion with "Intake Problems". LCA does look like having spring loaded blow-in doors like Jaguar. Please refer the take off photograph below.
http://defenceforumindia.com/jh4cz/assets/LCA-Tejas-10.jpg
His reply is ,"Thanks. Seen. If the reports are right then perhaps they need enlargement.
Thanks,once again."
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2.The R-73 has been test fired from the LCA several times. For this comment his answer was
"Thanks. Seen. If the reports are right then perhaps they need enlargement.
Thanks,once again."
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3.
Typhoon's fuselage length is 15.96 meter. rafale's fuselage length is 15.27 meter. Applying the same analogy you applied for tejas vs gripen, Do you think IAF selected a lemon as MMRCA winner because rafale is aerodynamically blunt compared to its contemporary Typhhon? .
For this prof Das did not even reply.
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4.
BARC: Bhabha Atomic Research Center: Computer Division[68]
ANUPAM-860/16 Node parallel processor, used for CFD work related to LCA engine intakes
Other versions of ANUPAM/16 Node (ex. ANUPAM-Pentium/16) are under development. This is a significant contribution to evolving field of Parallel Processing applications.
Do you think that people at BARC gave a wrong CFD enabled design for ADA?.
For the above comment his reply was,"
CFD will work only if you put in suitable"windage" factors. Was that done?I do not know",
which gives you no explanation at all.
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5.
Tejas's s contemporary gripen C which is 300 Kg more empty weight than tejas. So it too must be too heavy and should perform poorer than tejas considering it has an engine which gives 4 Kn lesser thrust than tejas while also being 300 kg overweight in its gripen C/D airframe. Is it true?
So what about gripen C/D's claim of mach 1.8 and supersonic at sea level?Is it correct or not?
Also the release to service document of tejas mk-1 at IOC-2 says tejas has achieved 24 deg AOA till now within the 80 percent opened flight envelope.
It also says supersonic at all altitudes. but you are saying it is supersonic only in dives. So what is the meaning of ADA's claim supersonic at all altitudes?
His reply was ,"
I will normally not reply to "Unknown" commentators.
One enduring confusion is that SAAB Gripen weight is the operational empty weight. The LCa's is the basic empty weight. B
But that is missing or obfuscating the point on which I hinge my doubt.
The LCA, by ADA's own admission is 1300 kilos overweight.
My simple contention is that an aeroplane that is 20% over the design weight CANNOT achieve Design performance. QED."
All the info given in his above reply is wrong. gripen has much higher empty weight and much lower wing area and much lower engine power in all its versions compared to corresponding tejas versions.
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6.
If a 6.8 ton empty weight 80 Kn engine Gripen C can achieve supersonic speed at sea level, why couldn't 6.5 ton empty weight 84 kn engine tejas mk-1 achieve supersonic speeds of mach 1.6 and mach 1.1 at sea leve(achieved while pulling out of a powerless(not powered dive) dive from 4 km to sea level altitude during flutter test in hot goan skies )
Also ADA has stated record in their website that tejas was modelled on F-16 XL with a vortex generating compound delta design instead of canard delta design with a view of reducing weight and having far lower wing loading for high altitude operations from himalayan forward bases.
they stated that they chose the compound delta design after it was conclusively proved in wind tunnel tests that canard delta design has not given them any agility advantage considering the weight penalty it imposed.
is it wrong or right?.
For this comment he hasn't replied till date!!!!
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The following is even more interesting exchange,
7.This comment is by Vishwasis Jha,---
Well No offence sir!!!I respect your knowledge and but you need to update yourself with latest happening in LCA. Now you are saying it is supersonic only in dives,that I must say is pure BS. When LCA navy can goes supersonic on hot goan sea with weight 400-500kg more than airforce version then how come you say that? Light Combat Aircraft Navy goes super sonic | Latest News & Updates at Daily News & Analysis
C'mon LCA fired dozens of R73 in trails and even in IRON fist exercise,it shows it swing rolecapbality with droping LGB,fired R73 and shoots chaff and flare,all within 50 secs.
His reply is----"
I am a little sceptical about the ADA's claims on the speeds for reasons given in the article. I also did a fuel burn analysis and certainly the aircraft would be fuel limited if it has to be back over base with enough fuel for a diversion of 70-80 n.m.,overshoot and landing."
For this vishwasis jha once again replied,"
Now you are sceptical Sir. You are ignoring plethora of media reporting and ADA june newsletter where they said that LCA Navy Crossed important milestone for going Supersonic over Goan sea.You are comparing Fuel burn analysis but you ignored simple things that LCA tejas touched transonic in 2013 AERO India in matter of few seconds.While the Engine you are talking about is same as Gripen Engine however its more powerful and efficient then RM 12.".
For the above reply from Vishwasis Jha he hasn't given any reply!!!!
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8.
Basic empty weight of gripen C is given as 6250 Kg in the following link.
http://------------------/threads/saab-gripen-news-and-discussions.18472/page-29.
tejas mk-1 comes in at 6500 Kg. So the difference is just 250 Kg. And Tejas has a significantly larger wing area and more volume for internal fuel.
SO there tejas mk-1 weighs just 250 Kg more than its very successful contemporary (just around 4 percent more), but has an engine that is 5 percent more powerful than gripen C. SO on the whole no reason to call it a heavy obsolete design that wont meet the specs.
For that 250 Ke extra basic empty weight it has a higher wing area giving it an advantageous lower wing loading which will help in Instantaneous turn regime.
Reply.
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9.
The Thrust to weight ratios of gripen C and its contemporary tejas mk-1 in half fuel internal fuel weight and with just two close WVR missiles config are almost the same(both in the 1.07 region, if I am right).
So tejas mk-1 performance wont fall significantly from gripen C performance on the reason of weight alone. Tejas mk-1 has a max take off weight of 13.2 tons where the engine thrust and lift drops close to 12 percent as per your old estimate.
Gripen C whose max take off is given as 14 tons is for cold climate conditions. So it wont lift as much in indian hot climate conditions based on your estimate. So tejas mk-1 doesnot compare unfavourably with its contemporary Gripen C.
The comments 8, 9 above were mine, For these he gave no replies at all,
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10.the comment is mine---"Please give us the operational and basic empty weight of both tejas mk-1 and gripen C. It will clear lot of things,"
His reply was ,"
The basic empty weight of the Gripen C is 5650 kg as per William Green which is pretty near what ADA was trying to achieve for the LCA with 5500 kg. Gordon Swanborough puts the operational empty weight at 6622 kgs. The two figures can be reconciled by the fact that Green was talking about the "LSP" Gripens and some more equipment went on board -say about 200-250 kilos at most- on the definitive Gripen C which would have an empty weight of 5800-5900 kgs. All other sources I have seen just put empty weight at 6622 without specifying what type of empty weight it is.Getting back, The rest was due to all the other stuff that goes to make aircraft operational including the unusable fuel that an aircraft must have when it is coming in to land should it be required to fly to another airfield ,carry out an overshoot and land and taxi back.
But to get back: The basic question is : Is the LCA overweight by 1300 kilos? If so then it cannot meet TO, range , climb, turn rate and acceleration and top speed parameters."
The above reply is simply deflecting the real issue gripen empty weight of 6652 KG is 150 Kg more than tejas mk1 empty weight of 6.5 tons officially given out by ADA. But professor instead of accepting this fact talks about, "
The two figures can be reconciled by the fact that Green was talking about the "LSP" Gripens and some more equipment went on board -say about 200-250 kilos at most- on the definitive Gripen C which would have an empty weight of 5800-5900 kgs." which is mere conjecture.
tejas has far higher wing area than gripen with 150 KG lesser empty weight which is a fact no one can deny. Then why call tejas underpowered while saying gripen is a good? The tejas weight aim of 5 tons was in 1984, But TAmil mani DG Aero of DRDO clearly talks about 1994 ASR by IAF for tejas . So we don't know whether weight additions were due to much higher requirements or origianl weight itself. ANyway tejas weighs less than Gripen in empty weight has more wing area than gripen(lower wing loading which is generally beneficial!!!) and has a few Kn extra engine power which is all the while deflected cleverly by prof Das!!!
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I made another series of comment ,the following 10, 11, 12 ,13,,,,,,,,,,,, Das has not replied till date,,,,,,
10.The empty weight of tejas as mentioned in IOC is 6.8 tons.
It must be operational empty weight.
because internal fuel is close to 2.7 tons. take off clean includes 2 R-73 missiles with pylons, which comes close to 200 Kg. And the ammo and other misc stores can come close to 300 KG. Adding 2.7+0.2+0.3=3.3 tons approx.
Take off clean weight is mentioned as 9.8 tons.
SO 6.5 + 3.3 =9.8 tons.
These are the weight figures for early LCA prototype,
TD-1 ------ 6,780 kg with Flight Test Instrumentation
TD-2 ------ 6,670 kg with Flight Test Instrumentation
PV-1 ------- 6,430kg (reduced 350kg of weight, with with Flight Test Instrumentation)
These figures are for the weight reduction effort carried out by ADA from an earlier article called Radiance of tejas by B. harry.
So by all evidence the 6.8 tons must be operational empty weight.
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11.
Broadsword: The Tejas LCA: improving performance with the current F-404 engine
According to the above interviwe of Ajai Shukla's with HAL people,
this flight test equipment weighs around 300 to 400 Kg. And in the same article it was clearly mentioned that further redesign of avionic mounts can shave off another 300 Kg weight.
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12.
Broadsword: The Tejas LCA: improving performance with the current F-404 engine
The 10.5 tons is the total weight of the Tejas, with full fuel on board; all 7 pylons fitted but not carrying weapons; and two outboard missiles being carried.
SO if we add 3.5 tons of weapon load it will come to 14 tons and exceed the 13.2 ton mtow.
So this 700 Kg weight reduction with removal of telemetry instruments (400 Kg) + redesigning of display subsystems will bring down the weight of tejas(with full fuel on board; all 7 pylons fitted but not carrying weapons; and two outboard missiles being carried) to 9.8 tons,
Which is what mentioned as take of clean by ADA in IOC. SO 9.8-3.3(fuel 2.6 tons+ seven pylons with two R-73 missiles on outboard pylons 400 Kg+misc stores like ammo 300 Kg) gives us an operational empty weight of close to 6.8 tons.
So by all available evidence the excess empty weight must have been rationalized and now the operational empty weight must be around 6.8 tons as declared by ADA.
SO please check with HAL and ADA and clarify. thanks.
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13.
Broadsword: The Tejas LCA: improving performance with the current F-404 engine
Tejas weighs 10.5 tons with all seven pylons fitted, two outboard pylons carrying two R-73 missiles with full internal fuel and ammo loaded in take off clean.
The LCA's designers say that the removal of telemetry instrumentation, which is essential during flight testing, will bring the Tejas' weight down by as much as 300-400 kilos. Re-engineering some of the displays and sub-systems within the cockpit will lop off another 300 kilos; the weight reduction of 600-700 kilos is expected to allow the carriage of more weapons.
SO 10.5 ton-700 Kg= 9.8 tons is what was given by ADA in IOC releases.
Fuel -2.65 tons,
allseven pylons +2 R-73 missiles =400 Kgs(approx)
Ammo+ misc stores=300 Kg. Total= 3.3 tons.
So clean config take off weight 9.8 tons- 3.3 tons = 6.8 tons.It could only be operational empty weight and not basic empty weight.
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SO prof Das doesn't even know whether tejas has lesser or more empty weight than "
it's contemporary(that is the exact word he uses) gripen",
and he does not know,
1. tejas has a spring loaded aux intake,
2.tejas has already validated R-73,
3. Doesn't know what windage was given by ADA to BARC for CFD,
4.Doesn't know the empty weight of any gripen variant or tejas variant correctly enough to make an objective comparison,
5.He doesn't belief that tejas broke sound barrier at sea level during flutter test in Goa, which is now in official ADA spec released by ADA after IOC-2,
Now you can decide which is a waste of time!!!!
LCA?
or,
taking Mr. Das seriously?
