LCA news and discussion

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Re: LCA news and discussion

Postby karthik » 12 Nov 2009 01:08

sumshyam wrote:
karthik wrote:In India we have the same thing all our engg kids want to join NASA, Boeing not ISRO or DRDO.


Its not always like that...I am an engineering student from an elite engineering college in India ...and I wanna join HAL...and It is not only me...but many other people from my college wanna join PSUs...!!!


Are you still in collage? When i did my engg not a lot of my friends wanted to get into it and those who wanted to get into it where sons or daughter of Government employees who wanted to carry on the family tradition of getting gov jobs, also dont get me wrong, it was the dullest lot the ones with no proper exposure who wanted to such gov jobs, the really creative and intelligent ones(i dont mean the toppers, i mean the ones who had ideas and thought out of the box) are always eyeing to work outside.

No offense but thats what i noticed.

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Re: LCA news and discussion

Postby skganji » 12 Nov 2009 01:14

Why is their so much dependence on Just DRDO for defence needs ?. Why can't DRDO be privitized like Indian Airways. See what happened to Air India and how the private airlines are flourishing in India.
It is Ironical that the trials of LCA are growing at a snail speed when the country desperately needs it . Abviously some thing is wrong here. Either the DRDO is not kept in the loop of the serious requirement of LCA or the Indian Air Force is not pressing the DRDO to deliver it quickly.
Are they going to get the IOC by next year ?. Even this looks like remote now....

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Re: LCA news and discussion

Postby skganji » 12 Nov 2009 01:16

"Its not always like that...I am an engineering student from an elite engineering college in India ...and I wanna join HAL...and It is not only me...but many other people from my college wanna join PSUs..." --- Work for few years in these PSU's then you will be frustrated and will be wanting to leave because of buerocracy and few opportunities to succeed or do some thing spectacular.

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Re: LCA news and discussion

Postby sumshyam » 12 Nov 2009 01:18

karthik wrote:Are you still in collage?

No offense but thats what i noticed.


Yes...I am still in college...You may be right...but one thing you have missed that...PSUs provide best training atleast in India...and bonds are not that binding...so...if you feel like being bored you can leave....and join XYZ...!!!

I am interested in HAL....as I am somewhat fascinated about this aerospace field...and HAL is the only company....[ISRO...don't visits campuses....you must be knowing it.].

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Re: LCA news and discussion

Postby karthik » 12 Nov 2009 01:43

sumshyam wrote:
karthik wrote:Are you still in collage?

No offense but thats what i noticed.


Yes...I am still in college...You may be right...but one thing you have missed that...PSUs provide best training atleast in India...and bonds are not that binding...so...if you feel like being bored you can leave....and join XYZ...!!!

I am interested in HAL....as I am somewhat fascinated about this aerospace field...and HAL is the only company....[ISRO...don't visits campuses....you must be knowing it.].


Well there is a strict policy not to derail the topic in BR. So this is not the right place to discuss anything other than LCA.

But looks like your mind is not made up on what to do in the future, i would tell you this much that your not takeing a bad decision, how many people get the opportunity to serve their country while doing something they like? That in itself is a great incentive, As Swami Vivekananda said "The secret to genius is chastity of thoughts", that is to completely be immersed in one idea or ideal. If the mind is diverted into doubt your energy is lost in confusion and doubt, so make up your mind on what you want to do and completely dedicate yourself to learning everything about this, that way you would be preparing for your interview to. Good Luck, hope you make up your mind.

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 14:59

Things start moving ... hopefully will not stop again ...

4 flights in 2 days
LCA-Tejas completed the 1223 Test Flights. (14-Nov-09)
LCA-Tejas completed the 1221 Test Flights. (13-Nov-09)
LCA-Tejas completed the 1219 Test Flights. (12-Nov-09)

2 flights in 12 day
LCA-Tejas completed the 1219 Test Flights. (12-Nov-09)
LCA-Tejas completed the 1217 Test Flights. (31-Oct-09)

1 flights in 10 day
LCA-Tejas completed the 1217 Test Flights. (31-Oct-09)
LCA-Tejas completed the 1216 Test Flights. (21-Oct-09)

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Re: LCA news and discussion

Postby Arun KS » 16 Nov 2009 16:33

Do we actually need so many test flights or we are waiting for some other test to be carried out?(Astra and AESA)?

username changed to Arun KS.
Rahul.
Last edited by Rahul M on 16 Nov 2009 18:07, edited 1 time in total.
Reason: edit.

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 17:49

sansmerci wrote:Do we actually need so many test flights or we are waiting for some other test to be carried out?(Astra and AESA)?


I think the last most important will be MMR and MMR with weapons testing. As many other tests are already done: slow speed taxi, basic flying, stress, lightening, Supercruise, Hot, cold, high altitude, visual weapons test, etc.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 19:09

RKumar wrote:
sansmerci wrote:Do we actually need so many test flights or we are waiting for some other test to be carried out?(Astra and AESA)?


I think the last most important will be MMR and MMR with weapons testing. As many other tests are already done: slow speed taxi, basic flying, stress, lightening, Supercruise, Hot, cold, high altitude, visual weapons test, etc.


from when tejas can Supercruise ??

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 19:15

karan_mc wrote:from when tejas can Supercruise ??


From wiki ....
its first successful supersonic flight followed on 1 August 2003.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 19:23

RKumar wrote:
karan_mc wrote:from when tejas can Supercruise ??


From wiki ....
its first successful supersonic flight followed on 1 August 2003.


Going supersonic and doing Supercruise are two completely different things all together

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 19:35

karan_mc wrote:Going supersonic and doing Supercruise are two completely different things all together

link
An important milestone of the Tejas aircraft flight test programme was achieved on 1 August 2003 when the TD-1 aircraft,piloted by Wg Cdr Vikram Singh, flew at a speed greater than the speed of sound (Mach 1.0). The aircraft reached 1.08 Mach at an altitude of 11 km. This was the 33rd flight of the Tejas TD-1 aircraft. Five days later, on 5 August 2003, during its 34th flight, the Tejas TD-1 aircraft, this time flown by Gp Capt R K S Bhadauria, again reached 1.15 Mach at 11 km altitude. During supersonic flight, the unstable (at subsonic speeds) aerodynamic configu-ration becomes stable. The air data probes, that sense air pressure and indicate aircraft speed and height, face a significant change in the flow field and pressures at supersonic speeds due to the formation of shocks. The aircraft air-intake also faces a stern test at supersonic speeds: it must give a good performance and ensure that supersonic buzz does not occur. Other challenges are posed by the drag of the aircraft; drag increases sharply at supersonic speeds and the aircraft requires much more thrust to overcome this air resistance. The aircraft structure must also be ‘flutter safe’ at supersonic speeds. After completing 61 safe test flights, the Tejas TD-2 aircraft is an being upgraded to enable it to operate in an expanded flight envelope.

As I am not sure if LCA did with or w/o afterburn and with or w/o weapons....as per wiki
Supercruise is sustained supersonic flight of an aircraft with a useful cargo, passenger, or weapons load performed efficiently and without the use of afterburners.


If I got wrong then kindly explain the difference...

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Re: LCA news and discussion

Postby Rahul M » 16 Nov 2009 19:55

there is no evidence till date that LCA has achieved supersonic speed (with or without external stores) without use of after-burners == no known instance of supercruise.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 20:05

Most Aircraft's use afterburners to achieve supersonic speed , in turn they reduce their combat radius has the fuel burns at the faster rate ,but in supercruise the aircraft does not use afterburners which means less consumption of fuel but it does not mean that aircraft will have same range in supercruise mode and in subsonic mode ,it will be higher fuel consumption but less compared to aircraft's using afterburners

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 20:09

karan_mc wrote:Most Aircraft's use afterburners to achieve supersonic speed , in turn they reduce their combat radius has the fuel burns at the faster rate ,but in supercruise the aircraft does not use afterburners which means less consumption of fuel but it does not mean that aircraft will have same range in supercruise mode and in subsonic mode ,it will be higher fuel consumption but less compared to aircraft's using afterburners

Is that the reason that we are looking for new engines (F414 or EJ200). Or it is independent to this problem.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 20:11

Rahul M wrote:there is no evidence till date that LCA has achieved supersonic speed (with or without external stores) without use of after-burners == no known instance of supercruise.


I agree with rahul here Tejas has not achieved supersonic speed w/o afterburners and it is highly unlikely that it ,we can see if Tejas MK-II can achieve that

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 20:18

RKumar wrote:
karan_mc wrote:Most Aircraft's use afterburners to achieve supersonic speed , in turn they reduce their combat radius has the fuel burns at the faster rate ,but in supercruise the aircraft does not use afterburners which means less consumption of fuel but it does not mean that aircraft will have same range in supercruise mode and in subsonic mode ,it will be higher fuel consumption but less compared to aircraft's using afterburners

Is that the reason that we are looking for new engines (F414 or EJ200). Or it is independent to this problem.


New engines are for more thrust requirements which iaf wants in Tejas ,current F404-GE-IN20 engine generates more than 19,000 pounds (85 kN) while new engines will have to be able to generate thrust of 95-100 Kilo Newton, Eurojet EJ200 has achieved supercruise in Euro fighter

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Re: LCA news and discussion

Postby RKumar » 16 Nov 2009 20:25

Thank you!!! :D

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Re: LCA news and discussion

Postby Rahul M » 16 Nov 2009 20:26

to my knowledge at the moment for all practical purposes(read: with external stores) only the F-22 and EF can supercruise, PAKFA is expected to have this capability. the su-35 and the gripen has bragging rights supercruise ability i.e supercruise in clean configuration.

so all in all, for a 4/4.5 gen aircraft, supercruise is a 'nice to have' capability rather than 'must have' capability.

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Re: LCA news and discussion

Postby SaiK » 16 Nov 2009 21:18

How much of a mission use is there to supercruise without full weapons load? zilch imho., and it should increase that much fuel consumption if not worse than using afterburner. Again, the mission profile changes.., and it should be a BVR engagement mostly, is my thought to use supercruise.. pretty helpful against chinese and beyond, and I don't think pakfa is pakicentric anyways..

BTW, supercruise also reduces the combat radius -correct? and, we need to also study mission profile, altitute etc.. to use supercruise.. If we can't supercruise for 5 minutes [for a raptoriskie role], say mach 1 then we have no use for supercruise is my guess. BTW, on the same lines supercruise for LCA could be scaled down to a minute or two., to finish off few strategic bases in pakibanistan.

Quite a bit of re-engineering is required for LCA to supercruise.. inlets reingerneering for higher thrusts, reduce shock waves, etc.. LCA should start changing its shape to resemble raptor or pakfa.. especially the front. Engine inlets are very important for supercruise is what I read.

..and btw, ot: why did the artists made pakfa look raptoriskie in the models?

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Re: LCA news and discussion

Postby Gaur » 16 Nov 2009 22:37

SaiK wrote:..and btw, ot: why did the artists made pakfa look raptoriskie in the models?

I have answered you in PAK-FA forum.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 22:38

but is supercruise even worth in a single engined and small fighter aircraft like Tejas ??? only other single engine aircraft claiming to have supercruise is Gripen ,how much will it save fuel or how much combat radius will it give to Tejas has to be studied before it can give clear or major advantage to the aircraft ,i mean consider that Tejas has 800km Combat radius and with Afterburner it comes down to 600km and with supercruise it numbers go up to 650km or 675km is it worth ?, it will have huge impact on bigger aircraft's like F-22 or Pak-fa in terms of range.

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Re: LCA news and discussion

Postby Rahul M » 16 Nov 2009 22:40

meaningful SC can only happen in a full internal weapons carrying a/c.

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Re: LCA news and discussion

Postby Gaur » 16 Nov 2009 22:56

karan_mc wrote:but is supercruise even worth in a single engined and small fighter aircraft like Tejas ??? only other single engine aircraft claiming to have supercruise is Gripen ,how much will it save fuel or how much combat radius will it give to Tejas has to be studied before it can give clear or major advantage to the aircraft ,i mean consider that Tejas has 800km Combat radius and with Afterburner it comes down to 600km and with supercruise it numbers go up to 650km or 675km is it worth ?, it will have huge impact on bigger aircraft's like F-22 or Pak-fa in terms of range.

Depends upon the penalty on range, but IMO super cruise will be a nice bonus for any a/c.
Sometimes it is necessary to reach the theater quickly and depending on the closeness of the airbase, range may/may not be an issue.
IMO becomes even more important for tejas as one of its major role would be air defence.
In case of a surprise attack, it would be crucial to reach the theater quickly.

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Re: LCA news and discussion

Postby karan_mc » 16 Nov 2009 23:04

Gaur wrote:
karan_mc wrote:but is supercruise even worth in a single engined and small fighter aircraft like Tejas ??? only other single engine aircraft claiming to have supercruise is Gripen ,how much will it save fuel or how much combat radius will it give to Tejas has to be studied before it can give clear or major advantage to the aircraft ,i mean consider that Tejas has 800km Combat radius and with Afterburner it comes down to 600km and with supercruise it numbers go up to 650km or 675km is it worth ?, it will have huge impact on bigger aircraft's like F-22 or Pak-fa in terms of range.

Depends upon the penalty on range, but IMO super cruise will be a nice bonus for any a/c.
Sometimes it is necessary to reach the theater quickly and depending on the closeness of the airbase, range may/may not be an issue.
IMO becomes even more important for tejas as one of its major role would be air defence.
In case of a surprise attack, it would be crucial to reach the theater quickly.


this is the exact same reason why super cruise was not considered for F-35 ,been a point air defence fighter Tejas is , super cruise should not be a required factor for MK-II

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Re: LCA news and discussion

Postby Picklu » 17 Nov 2009 01:43

Rahul M wrote:to my knowledge at the moment for all practical purposes(read: with external stores) only the F-22 and EF can supercruise, PAKFA is expected to have this capability. the su-35 and the gripen has bragging rights supercruise ability i.e supercruise in clean configuration.

so all in all, for a 4/4.5 gen aircraft, supercruise is a 'nice to have' capability rather than 'must have' capability.


As far as the bragging right is concerned, IIRC LCA went supercruise in the test program ahead of testing afterburner and when the observant jingoes bought that to the notice in the old LCA thread, J-Man confirmd LCA can do "supaah cruize" in level flight in clean config.

That was an improvement over HF-24 Marut which could go supersonic only during diving (we do claim it is Asia's first supersonic combat aircraft :twisted:) and the engine didn't even have afterburner.

So, we can brag about "supaah cruize" alright IMVHO

Whethere thas was/is useful during combat situation is a different question altogether :oops:

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Re: LCA news and discussion

Postby Rahul M » 17 Nov 2009 01:48

are you sure you are not confusing with the HF-24 with the afterburning engine ?

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Re: LCA news and discussion

Postby Picklu » 17 Nov 2009 02:28

Rahul M wrote:are you sure you are not confusing with the HF-24 with the afterburning engine ?


Sorry, did not get your question. Marut did not have an afterburner and still could go supersonic but only during diving.

It never came out in official news media that LCA can supercruise. However a news article came out stating the plan is on to start testing the afterburner by lighting for the firsttime while airborne. By that time, LCA had already gone supersonic as per the milestones maintained by ADA. So jingoes promptly started asking question in the old LCA thread and then Jagan clarified/confirmed. Should be there somewhere in the BRF archieves of LCA thread.

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Re: LCA news and discussion

Postby Rahul M » 17 Nov 2009 06:43

there was a test version of a HF-24 with more powerful engines that could supercruise but IAF was not interested.
I definitely remember jagan confirming this in some old thread. that however is gone now, but I did find this :
viewtopic.php?p=749362#p749362

it sounds very very unlikely that the LCA with its current engine can supercruise.

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Re: LCA news and discussion

Postby Picklu » 17 Nov 2009 08:26

Well, I do not have that post and hence can not verify that anyway unless Jagan himself confirms. However, one pointer is that LCA went supersonic in its 33rd test flight as per the news article quoted above. IIRC, the afterburner was not used for quite some time during the initial phase of the test flight program.

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Re: LCA news and discussion

Postby shiv » 17 Nov 2009 09:10

Picklu wrote:
Rahul M wrote:are you sure you are not confusing with the HF-24 with the afterburning engine ?


Sorry, did not get your question. Marut did not have an afterburner and still could go supersonic but only during diving.



This is what I used to believe - but a recent Vayu article says that the HF could do that in level flight without afterburning. I will try and get the quote/source. As far as I can tell the problem about supercruise is fuel consumption, not ability. Will be glad to know if I am wrong.

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Re: LCA news and discussion

Postby Jagan » 17 Nov 2009 11:15

The Marut can supposedly hit a top speed of Mach 1.04 or so in level flight. almost every other fighter that preceded it - Gnat, Hunter, Mystere could go Supersonic in a dive. So going supersonic in a dive is no big deal.

reg the Tejas,I remember posting that the LCA can go Mach 1 without afterburner. i.e supercruise - as that was what an aDA source told me. did anything change?

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Re: LCA news and discussion

Postby Rahul M » 17 Nov 2009 11:36

well considering that the dry TWR for LCA with the IN20 engine (for full loaded weight) comes to 0.52 it is a bit hard to see how that happens.

for a known supercruising jet, the EF for example, the corresponding dry TWR (again for full loaded weight) comes to 0.79. the decently powered but no supercruise mig-29 comes at 0.61.
and the LCA can manage SC with 0.52 ?
unless I'm making a huge mistake somewhere, it doesn't look right to me.

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Re: LCA news and discussion

Postby Jagan » 17 Nov 2009 11:45

Rahul M wrote:well considering that the dry TWR for LCA with the IN20 engine (for full loaded weight) comes to 0.52 it is a bit hard to see how that happens.

for a known supercruising jet, the EF for example, the corresponding dry TWR (again for full loaded weight) comes to 0.79. the decently powered but no supercruise mig-29 comes at 0.61.
and the LCA can manage SC with 0.52 ?
unless I'm making a huge mistake somewhere, it doesn't look right to me.


there is always a possibililty that guy was pulling my leg (knowing I will post it here) so dont take my word for it.

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Re: LCA news and discussion

Postby geeth » 17 Nov 2009 16:30

>>>for a known supercruising jet, the EF for example, the corresponding dry TWR (again for full loaded weight) comes to 0.79. the decently powered but no supercruise mig-29 comes at 0.61.
and the LCA can manage SC with 0.52 ?
unless I'm making a huge mistake somewhere, it doesn't look right to me.

LCA going supersonic at its max dry thrust may not be wide off mark, particularly when you think even Marut could do it. But this being misconstrued as supercruising in any meaningful way is the problem. The engine should have much more dry thrust power for supercruising, than that just required for reaching sonic speed. Then only it can sustain the speed and have some fuel economy/save time.

After all, what is the need for just reaching the sonic speed and add the additional wave drag, which in turn increases the fuel consumption?. This will affect the performance adversely, than aiding it.

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Re: LCA news and discussion

Postby shiv » 17 Nov 2009 16:56

Rahul M wrote:well considering that the dry TWR for LCA with the IN20 engine (for full loaded weight) comes to 0.52 it is a bit hard to see how that happens.


Rahul the TW ratio as far as I know has more to do with climb rate and loss of thrust while turning than the ability to accelerate in level flight. If you keep accelerating the thing forward it go as fast as is possible until air resistance stops it from going any faster I guess. I am no expert though.

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Re: LCA news and discussion

Postby Rahul M » 17 Nov 2009 17:02

geeth ji, if I understand correctly you mean that may be it reaches transonic region on dry thrust which is not sustainable ?

who knows, may be it supercruises in a dive ! :rotfl: :rotfl:


Rahul the TW ratio as far as I know has more to do with climb rate and loss of thrust while turning than the ability to accelerate in level flight. If you keep accelerating the thing forward it go as fast as is possible until air resistance stops it from going any faster I guess. I am no expert though.

shiv ji, those are all related parameters related to the aircraft's energy. it can trade speed for height and vice versa and all of that comes from the engine thrust.

in level flight with no acceleration, the thrust has to negate the drag in order for the a/c to move.

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Re: LCA news and discussion

Postby shiv » 17 Nov 2009 19:47

Rahul M wrote:shiv ji, those are all related parameters related to the aircraft's energy. it can trade speed for height and vice versa and all of that comes from the engine thrust.

in level flight with no acceleration, the thrust has to negate the drag in order for the a/c to move.


I do accept that but unless you have a figure for drag you cannot relate t/w ratio to final velocity. The only "example" I can give is the theoretical ion rockets in a vacuum which are supposed to give a very low acceleration for weeks to reach tremendous velocities.

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Re: LCA news and discussion

Postby Vivek K » 17 Nov 2009 20:27

Is supercruise of paramount importance to the LCA? Or would getting 4-5 squadrons of it in service armed with a decent array of weapons be critical given the power play with China presently?

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Re: LCA news and discussion

Postby shiv » 17 Nov 2009 21:10

Vivek K wrote:Is supercruise of paramount importance to the LCA? Or would getting 4-5 squadrons of it in service armed with a decent array of weapons be critical given the power play with China presently?
Valid point. The latter of course. But the point is that a lot of aircraft can supercruise in theory, but it is the range and fuel consumption that is the problem. So they can't "cruise" very far.


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