LCA news and discussion

Kartik · Post by **Kartik** » 09 Dec 2009 04:15

RKumar wrote: more then 2 flights a day (since 26-Nov)
Keep it up HAL, ADA, IAF
Did anyone noticed LSP2 is making a flight daily??

It might have simply been a chase aircraft. Its happened in the past as well- a Tejas TD or PV being used as chase aircraft for another Tejas TD or PV. That would imply that they'd be monitoring the telemetry on either one, not both. so they may not be validating more parameters just by flying 2 aircraft.

SaiK · Post by **SaiK** » 09 Dec 2009 04:29

it just can't be mph since 1350mph would be around 2172kmph [i am just word swapping here, not mach calculation].

if may guess, it could be 1.35 mach! [~1012.5mph]

srai · Post by **srai** » 09 Dec 2009 04:31

Kartik wrote:I wish someone with a wee bit more attention to detail had written that report on the Tejas clocking its highest speed to date. he's either mixed up between kmph and mph or he's simply made a big error in writing down what was said. Another typo - its Air Commodore Rohit Varma, not Commander. He is ex-IAF, not IN.

It is probably mph because when you do the conversion 1,350 mph is close to LCA's designed top speed of 1.8.

1,350 mile/hour (mph) = 1.773 499 074 3 Mach

Otherwise, if it is kph, then it must be LCA's top speed at sea level at around Mach 1.1.

1,350 kilometer/hour (kph) = 1.102 001 234 3 Mach

http://www.onlineconversion.com/speed_common.htm

http://www.unitarium.com/speed

Craig Alpert · Post by **Craig Alpert** » 09 Dec 2009 04:39

Kartik wrote:
Craig Alpert wrote: o and by the way it ALWAYS MATTERS if the aircraft was flying that speed in a clean config or if it was fully loaded, because if god forbid it had to ever go on a mission with full load, and required to achieve that speed, well let's just say the rest will be history..
you can safely assume that it was at least for sure carrying two wing tip pylon R-73 dummies at least, which simulate its weight and drag characteristics. so its not in "clean" config as such. maybe it was also carrying drop tanks..who knows ?

Flying fast with empty weight is a no big deal, if you can't tap on the speed when you really need it during combat with combat load, but then again you probably were only thinking about DIVING..
since no data is available on whether or not the Tejas has any issues with high speed with stores, please desist from speculation. you don't know if it flew with stores, or with only 2 dummy R-73s. in that event, please don't talk as if the Tejas is speed-compromised.

Boss,
1) I didn't speculate, I was replying to the previous thread.
2) Like you, I wished for clear data and that's all I said in my post - never said anything about Tejas's speed being comprised. Thought out loud whether or not it was in that scenario. You took my quote and misrepresented it as something else (which as I stated, was in reply to the previous post)
3) I'm all up for the positivity, sure hope that it had a drop tanks and 2 dummies - no better way to kick start this BRfite jingo's wet dreams.
4) Since no data is available, I'll leave each to it's own. I'll cease and desist.

Kartik · Post by **Kartik** » 09 Dec 2009 04:51

ankit-s wrote:When the aircraft is diving, its known as negative-G force, far from cobra manuvour of positive G Force of 9+..........With G-suit on you would be okey, other than that you have to face the music.

nope. its positive g force when you basically are in a dive and then especially so when you pull up- that’s when the maximum g-force would've been experienced. negative g-force is experienced when the pilot is basically pushing the control column in a direction that pushes the aircraft away and against the radius of the turn its performing.

However negative g will never cause a black out, because it pushes blood into your head. You could cause high negative g by pushing on the stick. Most fighter airplanes are only built to take about 3 negative g.

high negative g's can cause what is called a red-out. basically the pilots's eyes can be damaged, with blood vessels exploding.

abhiti · Post by **abhiti** » 09 Dec 2009 04:52

Check out pg 5 below for the flutter test planned for LCA.

http://www.aero.iisc.ernet.in/kartik/INCAST_sudha5.pdf

Cain Marko · Post by **Cain Marko** » 09 Dec 2009 07:05

It is unlikely that the Tejas was heavlily loaded (if at all) for the 1300+kmph speed, which btw is indeed a SOLID achievement esp. considering the interim engines, altitude and the location. Kudos to all, speaks volumes about the design.

Many a/c can't achieve that kind of speed at low level flight. Even the fabled fulcrum only has a stated top speed of 1500kmph at low level. I doubt the shornet can even go supersonic at low altitude with a solid A2G loadout.

Once again, this is v.promising; can expect some stellar stuff by all accounts when the new engines are chosen.

CM.

Kartik · Post by **Kartik** » 09 Dec 2009 07:14

abhiti wrote:Check out pg 5 below for the flutter test planned for LCA.

http://www.aero.iisc.ernet.in/kartik/INCAST_sudha5.pdf

thanks ! excellent material ! I think that it may well give an explanation of what the Air Commodore was hinting at..the lowest corner point of the flutter testing envelope at 7 km altitude is around 1370 kmph..maybe he was referring to successful completion of that proposed testing point with stores, which may be a big step towards IOC.

SanjibGhosh · Post by **SanjibGhosh** » 09 Dec 2009 07:20

Tejas aircraft trials end successfully
http://timesofindia.indiatimes.com/city ... 316448.cms

The LCA is the first supersonic fighter being manufactured indigenously by Hindustan Aeronautics Limited. When 20 such LCA will be manufactured it will be given to the Air force and the other 20 to the Navy, it is a package of 40 LCA

20 for navy ..... ??? !!!

karan_mc · Post by **karan_mc** » 09 Dec 2009 07:58

The HAL has manufactured four aircraft which are being put under rigorous testing by fighter pilots.

which four aircraft's are they talking about only LSP1 and LSP-2 have taken to air are they referring to LSP-3 and LSP-4 which are already conducting Ground Trials ?

SaiK · Post by **SaiK** » 09 Dec 2009 08:13

CM, where did in the news it said those speeds were at sea or low level?

--
What is Operational Clean configruation? without weapons load? that is the slide with flutter test for pv2.

From the graph, the flutter tests are done so far for Tejas are:-

1. At mach 1.2, max 12,500 meters (41010 ft) - highest flutter test height reached by LCA.
2. At mach 0.9, min 3,900 meters (12795 ft) - Lowest level flutter test level.

So, if we are refering the flutter test then we are not hopefully talking about max speed attained by LCA. These test results were separate correct?

The proposed, and not completed tests include min 1000 meters (3280 ft) at Mach 0.85 and mach 1.1.
There is also proposed flutter test at mach 1.6 @ 7000 meters (22,965 ft).

Of course, these data is per June 2008. However, the proposed is what would have happened in the test envelope.

Excellent tech matterial there, for many of those LCA geeks.

suraj p · Post by **suraj p** » 09 Dec 2009 08:32

## am now desperately waiting for some good news on the front of radar integration. ###

Why?.. is there any news of new development in CABS/MMR? I thought ELTA's EL/M was mated and was successful.

Kartik · Post by **Kartik** » 09 Dec 2009 08:50

SaiK wrote:CM, where did in the news it said those speeds were at sea or low level?

this article states that the trials were done at sea level.

Light combat aircraft (LCA) Tejas notched a speed of over 1,350 km per hour -- the fastest by an indigenously-made fighter aircraft -- during its sea level flight trials off Goa Tuesday, a senior Indian Air Force official said.

Tejas which is undergoing rigorous testing in saline, humid marine conditions in and off the coast of Goa, had performed admirably in the two-week long trials in Goa, Air Commodore Rohit Varma who is also the commanding officer of the Bangalore-based National Flight Testing Centre (NFTC) told reporters at the INS Hansa naval base Tuesday.

"The trials which lasted for two weeks comprised of flutter clearances, weapons firing, performance, stability and avionics validation. The LCA is the first supersonic fighter being manufactured indigenously by Hindustan Aeronautics Limited (HAL)," Varma, an elite pilot himself, said.

As part of the initial operational clearance, the Aeronautics Development Agency (ADA) had inducted three aircraft to Goa for conducting various sea-level flight tests, he said.

Singha · Post by **Singha** » 09 Dec 2009 09:00

mashallah I see visions of "michael gant" flying his firefox low over the barents sea, the wingtip vortices leaving a splash in the water and making a supersonic run directly over BCGN Riga...firing off a anab missile at a ka28 just taking off from the stern deck...

Jayram · Post by **Jayram** » 09 Dec 2009 09:24

This is interesting. The document at http://www.aero.iisc.ernet.in/kartik/INCAST_sudha5.pdf at page 5 is very close to the actual parameters that we can discern from the flight tests in Goa. Note the graph on Page 5 corresponds to the gradual opening up of the flight envelope upto the point when this IAF decided to go public with the mach numbers and sea level testing.. The 900 feet elevation corresponds nicely to one of the test points identified there.
It does look like
a) LCA is behaving very closely or exceeding the design numbers and
b) we might be reaching end of one milestone wrt fluttter testing..
Caveat I am just a regular jingo..
Some uber qualified jingos will be able to discern more.

vina · Post by **vina** » 09 Dec 2009 10:34

Jayram wrote:This is interesting. The document at http://www.aero.iisc.ernet.in/kartik/INCAST_sudha5.pdf at page 5 is very close to the actual parameters that we can discern from the flight tests in Goa.

Thanks. Yes. That is an interesting graph. So basically what Sudha PV's paper is saying is that the LCA is designed for a max Calibrated Air Speed (CAS) of 1354 km/h and that has been tested. If you you follow the CAS line at sea level it is Mach 1.1 and it reaches Mach 1.6 at 6500m or so and after that it is Mach limited .

DDM wont be able to make out the difference between CAS and TAS even if someone hit them on their heads with a monkey wrench and told them. But hey who cares. Yeah at close to sea level the CAS will be equal to ground speed at ISA conditions , since Goa will have temperatures greater than ISA (ISA +20 or so) , applying density correction, the actual ground speed was probably a fair bit higher than 1354km/h.

But anyways, it is heartening to note that the Tejas has been tested for it's highest designed dynamic pressure conditions successfully.

That brings me to the point. Why this mach 1.6 limit at high altitude ? That sort of seems a bit artificial. If the 1350 KMHR CAS line is allowed a secular rise with altitude beyond 6500m, it should be able to go to Mach 1.8 to Mac 2.0 or so at 10000m or so. What is limiting that I wonder. The inlet design ?.

Maybe that speed beyond Mach 1.6 is tactically important and hence wasn't bothered with. But the airframe certainly has the potential to get there without too much of a stretch at altitude. Hmm.. Mach 2 would have been a nice point to make in a "pissing contest".. DDM can always beat you up . Expect blaring headlines on the lines of " Mirage 2000 from 1979 or Mig 21 from 1961 can do Mach 2.2 while LCA from 2011 can do only Mach 1.6" and hence LCA bad etc. One can always turn around and point at Rafale and Eurofighter and say that they are not Mach 2 either I guess.

nachiket · Post by **nachiket** » 09 Dec 2009 11:13

vina wrote: Maybe that speed beyond Mach 1.6 is tactically important and hence wasn't bothered with. But the airframe certainly has the potential to get there without too much of a stretch at altitude. Hmm.. Mach 2 would have been a nice point to make in a "pissing contest".. DDM can always beat you up . Expect blaring headlines on the lines of " Mirage 2000 from 1979 or Mig 21 from 1961 can do Mach 2.2 while LCA from 2011 can do only Mach 1.6" and hence LCA bad etc. One can always turn around and point at Rafale and Eurofighter and say that they are not Mach 2 either I guess.

Well who cares what the DDM says. The IAF guys won't fall for that crap since they know the lack of importance of a Mach 2+ max speed that can only be achieved for a few seconds. But you could be right about the max speed being limited by the inlet design. If that is the case I'm wondering if we might see a Mk III version with modified inlets after the immediate needs of the IAF are met by the Mk I and II versions.

What I'm interested in the max sustained speed achieved without using afterburners, but I guess there is little chance of that being declared.

vina · Post by **vina** » 09 Dec 2009 11:16

That brings me to the point. Why this mach 1.6 limit at high altitude ? That sort of seems a bit artificial. If the 1350 KMHR CAS line is allowed a secular rise with altitude beyond 6500m, it should be able to go to Mach 1.8 to Mac 2.0 or so at 10000m or so. What is limiting that I wonder. The inlet design

Hmm. The YellCeeYea has a fully shielded inlet, which as long as the wing is below the Mach angle cone will see no shock effects and see only subsonic airflow.

Can some young Mujahid with good Kompooter skills quickly do a favor ?. In a plan form picture of the LCA, can someone calculate the sweep back angle of the part forward of the crank in the wing ? If the sweep is 51.3 degrees or so, that is the angle equivalent to Mach 1.6.

A wing sweep of 60 will give you a Mach 2 wing .

Cain Marko · Post by **Cain Marko** » 09 Dec 2009 11:27

Maybe that speed beyond Mach 1.6 is tactically important and hence wasn't bothered with.

Vinaji,

I presume You mean unimportant ? Btw, what will the higher thrust engines (414s or EJ200s) mean to such parameters? More importantly, can we expect zabardast (ahem supersonic) speeds without ABs? The dry thrust on the EJ200s is certainly impressive; more than the GE-414s I read somewhere.

CM.

pralay · Post by **pralay** » 09 Dec 2009 11:49

here are speeds of fighters at sea-levels

JAS-39 A/B Gripen ( reference )
Maximum Speed at Sea Level - 1,225 km/h

EuroFighter Typhoon ( reference )
# At sea level: Mach 1.2[173] (1470 km/h / 913.2 mph) [174]

Su30MKI ( reference )
(a 1350 km/h ground-level speed)

F-22( reference )
at sea level: 920 mph (1,480 km/h), Mach 1.2

Rafale ( reference )
at sea level: 864 mph (1,390 km/h), Mach 1.135

Mig29K ( reference )
at sea level: 670 knots (771 mph; 1240 km/h) - sea level.

F-18SH ( reference )
at sea level: 835 mph (1,350 km/h), Mach 1.1

J-10 ( reference )
915 mph (1,470 km.h), Mach 1.2

Mig-21 ( reference )
at sea level: 800 mph (1,275 km/h), Mach 1.05

If we consider the references reliable, we can conclude our bird is performing quiet well with GE404.
I hope Tejas MKII with new engines will outperform most of the above!

krishnan · Post by **krishnan** » 09 Dec 2009 12:02

30 test flights in about 10 days

sumshyam · Post by **sumshyam** » 09 Dec 2009 13:11

vina wrote:If the sweep is 51.3 degrees or so, that is the angle equivalent to Mach 1.6.

A wing sweep of 60 will give you a Mach 2 wing .

Vina...how does it work....i don't get it...can you elaborate concerned concept...I would be happy to learn.....you can also mail me...!

RKumar · Post by **RKumar** » 09 Dec 2009 14:48

‘India can manufacture only 8 Light Combat Aircraft a year’

Armed with air to air, air to ground missiles and a bomb carrying a 1,000 pound payload, the LCA, which clocked in excess of 1,350 kmph during a trial off Goa Tuesday, is expected to cost Rs.150 crore per aircraft.

manjgu · Post by **manjgu** » 09 Dec 2009 17:41

curious to know how is set of 'test cases' developed to validate LCA ?

shravan · Post by **shravan** » 09 Dec 2009 17:52

Successful flight flutter test for Tejas

INS Hansa Base (Goa), Dec 9 (PTI) The aircraft dived towards the sea as the pilot lifted his hands off the control stick for five seconds. In such a short duration, it had plummeted from four kilometres above sea level to just 900 metres before the pilot hit to the throttle again to take to the skies.

Vivs · Post by **Vivs** » 09 Dec 2009 19:54

Here is an article which says Naval LCA tests too have begun

http://www.thaindian.com/newsportal/ind ... 86493.html

Gagan · Post by **Gagan** » 09 Dec 2009 21:51

That's incorrect isn't it?
What it should say is that the LCA testing is going on at a Naval airbase.
The Naval version will have an inclined cockpit and ?ailerons, and this prototype is in development.

ankit-s · Post by **ankit-s** » 09 Dec 2009 22:34

I Assumed that in this case he had the liberty of deciding how he wanted to test the negative G's.

A test pilot flies new aircraft in specific (given) maneuvers, allowing the results to be measured and the design to be evaluated.

The cardinal rule here, akin to Aerodynamical (Bible) commandment for the test pilot:

Thou shall not deviate from the chosen path!

The test pilot has to follow text book type maneuvers.

There was no room for assumption (in your case), if you were cognizant of the above!

Bye 4 now.....and have a good one.

SaiK · Post by **SaiK** » 09 Dec 2009 23:43

RKumar wrote:‘India can manufacture only 8 Light Combat Aircraft a year’

Armed with air to air, air to ground missiles and a bomb carrying a 1,000 pound payload, the LCA, which clocked in excess of 1,350 kmph during a trial off Goa Tuesday, is expected to cost Rs.150 crore per aircraft.

approx $32~33M per LCA!

shetty · Post by **shetty** » 09 Dec 2009 23:53

SaiK wrote:
RKumar wrote:‘India can manufacture only 8 Light Combat Aircraft a year’

Armed with air to air, air to ground missiles and a bomb carrying a 1,000 pound payload, the LCA, which clocked in excess of 1,350 kmph during a trial off Goa Tuesday, is expected to cost Rs.150 crore per aircraft.
approx $32~33M per LCA!

Wow!!!

Raveen · Post by **Raveen** » 09 Dec 2009 23:56

SaiK wrote:
approx $32~33M per LCA!

Less than the cost of a M2k upgrade...I say build till your hands hurt and then build some more. We shouldn't stop at 220, heck there is beauty in sheer numbers as well.

SaiK · Post by **SaiK** » 10 Dec 2009 00:18

Raveen wrote:
SaiK wrote:
approx $32~33M per LCA!
Less than the cost of a M2k upgrade...I say build till your hands hurt and then build some more. We shouldn't stop at 220, heck there is beauty in sheer numbers as well.

yes.. by public-private partnership, we can boost this at a faster rate..

Kartik · Post by **Kartik** » 10 Dec 2009 00:43

Vivs wrote:Here is an article which says Naval LCA tests too have begun

http://www.thaindian.com/newsportal/ind ... 86493.html

that’s an incorrect report. the N-LCA prototype hasn't even been rolled out yet, not to speak of all the various ground tests that need to be done, taxi tests and then only anything like flight tests. but now that the PV-5 has flown, some of its flight test data will help in giving an idea on how the N-LCA will fare since its based on the twin-seater.

Kartik · Post by **Kartik** » 10 Dec 2009 00:46

SaiK wrote: approx $32~33M per LCA!

that includes ground support equipment, simulators and training. that’s cheap if you ask me, considering what you're getting for it. a Gripen C/D of nearly same size, engine and overall capabilities will cost at least $50-55 million if not more for a similar package.

Craig Alpert · Post by **Craig Alpert** » 10 Dec 2009 01:06

Kartik wrote:
SaiK wrote: approx $32~33M per LCA!
that includes ground support equipment, simulators and training. that’s cheap if you ask me, considering what you're getting for it. a Gripen C/D of nearly same size, engine and overall capabilities will cost at least $50-55 million if not more for a similar package.

Is that number for Exports or for the Home country?? A couple of posts, earlier, someone made a comment on the French jet costing ~ $ 41-2 Mil a pop, well that's the price for export/upgrade. The price the Frenchies paid for Mirages were $23 Mil (source wiki) and even if one were to assume this did NOT include grnd support, sims and training, add all that and the price is EQUAL to that of the LCA.. However, the numbers order by French and that of LCA are MILES apart and hence, when more numbers are ordered by the IAF/IN the prices should come down significantly to say about ~ $28 MIL a pop!
Economies of Scale, tend to tilt the favour in home countries, as manufacturers make higher (insane at times) amount of profits when exporting as oppose to selling it at home.. Case in point (f-16s @ home cost $20 mil a Pop, Kashmiri Shawls, Wheat, etc..)

SaiK · Post by **SaiK** » 10 Dec 2009 02:05

SEE YAY!

--

So that ddm report of 1350kmph was for that 1000 mtr altitute/mach 1.1 proposed flutter test, that was done. (1350kmph->mach 1.27 @900 meters) correct?.

abhiti · Post by **abhiti** » 10 Dec 2009 02:54

vina wrote:Hmm. The YellCeeYea has a fully shielded inlet, which as long as the wing is below the Mach angle cone will see no shock effects and see only subsonic airflow.

Can some young Mujahid with good Kompooter skills quickly do a favor ?. In a plan form picture of the LCA, can someone calculate the sweep back angle of the part forward of the crank in the wing ? If the sweep is 51.3 degrees or so, that is the angle equivalent to Mach 1.6.

A wing sweep of 60 will give you a Mach 2 wing .

I have tried finding the angle but unsuccessful so far. There was an old study "an approach to high angle of attack testing for lca" which had exact angles. I cannot download it no more.

SaiK · Post by **SaiK** » 10 Dec 2009 05:29

1 The flutter margin method is successfully applied for Tejas
analysis data(both Subsonic and Supersonic) and the
prediction capability has been demonstrated.
2 Even though the flutter prediction equation is satisfactory in
the subsonic and supersonic region,it is inadequate for
configurations which may flutter in the transonic region.

We can expect more test at transonic speeds!

Jayram · Post by **Jayram** » 10 Dec 2009 06:09

Ok Vina - I will bite - downloaded some freeware and this the result. The red line and the angle therein is the one we are after.
The angle seems to be around 142 deg measured from the horizontal plane and therefore around 52 deg +/- sweptback from vertical. Not sure if I am measuring it exactly since there is some eyeballing required...
Any and all errors are mine and mine only..

Rahul M · Post by **Rahul M** » 10 Dec 2009 06:49

yes, leading edge sweep back angle is ~ 52 deg.

what vina ji mentions is the theoretical sweep for 2 mach, but as we can see from the graph, in practice (historical trend line) 52 deg sweep is used for >1.8 mach flight. there are other factors involved which determine this along with the mach cone considerations.
I'm however not sure how the double crank affects all this.