LCA TEJAS MK1 & MK1A: News and Discussion

[Aniruddha Mulay]

If we have a war with china in near future, our airforce is going to get outclassed real bad.


Severely lacking awacs, refuellers, dedicated ew aircrafts and only 36 4.5 gen aircrafts with proper bvr combat capability.

Nice Joke, anything else Exfart

 

[Shuturmurg]

Nice Joke, anything else Exfart

Sorry shaktimaan !! India superpowa !!! India best airforce !!!

 

[MiG-29SMT]

LCA Tejas Arial Display at Singapore Air show...

cool video, I confess I like more the naval version with LEVCONs, but still LCA is a beautiful aircraft

 

[Roland55]

I like seeing pics of the airshow, but..im really waiting for ASTRA..

 

[lcafanboy]

 

[THESIS THORON]

OH, yes they just made a better promotional video than HAL.

HAL's videos have cringe voiceover

 

[vidhwanshak]

 

[Bleh]

 

[FalconSlayers]

 

[Pazhassiraja]

As there was a recent conversation in DFI regarding wing area and drag, I have a doubt regarding the role of Tejas. It is known that Tejas was conceived as a point interceptor replacing Mig-21 and later it was modified for multirole operations. If it were a point interceptor, why had the designers selected a large wing area unlike the Mig-21 which has a smaller wing area and is famous for its agility & acceleration?

 

[SwordOfDarkness]

As there was a recent conversation in DFI regarding wing area and drag, I have a doubt regarding the role of Tejas. It is known that Tejas was conceived as a point interceptor replacing Mig-21 and later it was modified for multirole operations. If it were a point interceptor, why had the designers selected a large wing area unlike the Mig-21 which has a smaller wing area and is famous for its agility & acceleration?

Other members will give long explanation, but Ill give you the short one.

The design consultant for Tejas was Dassault. Dassault has great experience in Delta wing designs (Mirage, rafale, etc). And there is no definite "better" design between delta vs traditional. So, they utilised the experience of consultant to have a design which they were comfortable with. And delta wings do have a definite advantage in dogfights, so as a point interceptor it helps.

 

[Bleh]

If it were a point interceptor, why had the designers selected a large wing area unlike the Mig-21 which has a smaller wing area and is famous for its agility & acceleration?

The (not so)long answer now...

Because BVR & SAM become better. There no need for a jet to rush at bandits at Mach2 to get close enough. LCA is a point defence interceptor. Its job it to ensure safety of a local area, like say Dhillion's action above Srinagar Air Base.
Mig-25 are not needed. Mig-31 is a keepsake.

Also you're concept is wrong. Jf-17 will have much higher drag than Tejas (you can tell with its long level flight & short turns in displays), just like F-18 is famously draggy, compare Rafale's much high energy displays with its very very slow speed ones. There's more to it than just wing area.

View attachment 138763

Note that they now prefer twin-800lt tanks with the central 725lt tank, instead of the older practice of twin-1200lt... I suspect this combo results in more overall drag efficiency.

 

[ersakthivel]

As there was a recent conversation in DFI regarding wing area and drag, I have a doubt regarding the role of Tejas. It is known that Tejas was conceived as a point interceptor replacing Mig-21 and later it was modified for multirole operations. If it were a point interceptor, why had the designers selected a large wing area unlike the Mig-21 which has a smaller wing area and is famous for its agility & acceleration?

no one designs a point defence interceptor

with the world's lowest wing loading of 255.2 kg/m2,

painstaking fly by wire
all digital 4 channel software
negative stability flight profile
which requires decades of flight testing to perfect,

if they wanted a point defence interceptor
that just goes in fast and fires off its missiles
at the enemy

they would hv simply copied the
N number of aerodynamically obsolete,
high wing loading
positive stability
crucifix designs like jf17 etc,
throwing in A leading-edge root extension (LREX)

and would hv got it off the rails atleast a decade earlier
as they dont require that much testing.


this "point defence fighter tag" fr tejas is from tech illiterates,


within its range it can do almost everything that a 4.5 th gen modern european fighter (swing role or omni role ) can do


Its low wing loading enables sharper turns on vertical plane , crucial in skies above Himalayas, and higher takeoff loads from high altitude airfields like Leh,

regarding drag
where does it hides in tejas,

1.When it achieves the same sea level top speed as that of SU30 MKI in sea level hot temp conditions of Goa,
2.while doing a red eye turns
3.while doing couple of hundred meter minimum radius turns where it's nose direction changes 180 degree within 7 seconds
4.while completing a vertical loop in 19 seconds(it did half vertical loops in singapore within 10 seconds , so many times,
5. while flying a ferry range of 3200 plus km with three drop tanks to singapore
6. lifting close to 3 tons from Leh(60plus percent of normal MTOW),
7.breathtaking vertical charlies and while rolling on top of vertical loops with so much energy to spare

I just hope somebody answers these questions,

 

[ersakthivel]

only fools talk about plain drag,

whats crucial is the lift to drag ratio,

other than fuselage and vertical tail, which only produce drag, remaining large cranked delta wing area of tejas produces enormous lift, besides drag,

At high AOA when the drag becomes high ,
tejas cranked delta wing transitions to vortex based lift
that attaches to the upper wing area
due to lower sweep angle of inner cranked delta wing
fr tighter Instantaneous Turn Rate (ITR) and sharper nose pointing ability,

with the advent of high offbore HMDS cued WVR missile ( which are very hard to defeat in close combat when cued visually by pilot)

the spitfire era cartwheeling in the sky
to get into the turn of bogey
fr a gunfire tactic,
which is the forte of the "low drag" high Sustained Turn Rate (STR) crucifix plan form
has got lower precedence in close combat,
because the High ITR delta wd hv already finished off these high STR crucifix with sharper turn enabling them to fire their high off bore HMDS cued CCMs first


ANd indian atmospheric condition saps a substantial amount of wing lift and engine thrust , so tejas wing area was choose n with all these factors in mind

This wing form has been proved in tens of thousands of hours of software simulations and flight testing over decades, that I read in the net, ADA is applying the same tejas wing loading spec to Tejas Mk2 and stealth AMCA as well

 

[Pazhassiraja]

no one designs a point defence interceptor

with the world's lowest wing loading of 255.2 kg/m2,

painstaking fly by wire
all digital 4 channel software
negative stability flight profile
which requires decades of flight testing to perfect,

if they wanted a point defence interceptor
that just goes in fast and fires off its missiles
at the enemy

they would hv simply copied the
N number of aerodynamically obsolete,
high wing loading
positive stability
crucifix designs like jf17 etc,
throwing in A leading-edge root extension (LREX)

and would hv got it off the rails atleast a decade earlier
as they dont require that much testing.


this "point defence fighter tag" fr tejas is from tech illiterates,


within its range it can do almost everything that a 4.5 th gen modern european fighter (swing role or omni role ) can do


Its low wing loading enables sharper turns on vertical plane , crucial in skies above Himalayas, and higher takeoff loads from high altitude airfields like Leh,

regarding drag
where does it hides in tejas,

1.When it achieves the same sea level top speed as that of SU30 MKI in sea level hot temp conditions of Goa,
2.while doing a red eye turns
3.while doing couple of hundred meter minimum radius turns where it's nose direction changes 180 degree within 7 seconds
4.while completing a vertical loop in 19 seconds(it did half vertical loops in singapore within 10 seconds , so many times,
5. while flying a ferry range of 3200 plus km with three drop tanks to singapore
6. lifting close to 3 tons from Leh(60plus percent of normal MTOW),
7.breathtaking vertical charlies and while rolling on top of vertical loops with so much energy to spare

I just hope somebody answers these questions,

Thanks Shri. Sakthivel. I have already mentioned that Tejas is currently multi-role. But my doubt was regarding the motivation towards the choice of the current wing design at the time of its conceptualization when Tejas was envisaged to perform the role of Mig-21. And this has been well explained by Bleh & SwordofDarkness

 

[ersakthivel]

Thanks Shri. Sakthivel. I have already mentioned that Tejas is currently multi-role. But my doubt was regarding the motivation towards the choice of the current wing design at the time of its conceptualization when Tejas was envisaged to perform the role of Mig-21. And this has been well explained by Bleh & SwordofDarkness

Tejas was never envisaged to "perfom the roll" of Mig21,
If that was so they would hv chosen a 1970s crucifix with LREX design,

Tejas was to "replace" Mig 21 in IAF

just like rafale is "replacing" the jags and mirages in strike rolls in future, DOes that mean rafale has to adhere to the aerodynamics of jags and mirages?

same logic goes fr Tejas too . replacing an obsolete fighter doesnt mean that it has to "exactly" fit in the aerodynamic philosophy of the older fighter,

while replacing the Mig 21, Tejas was expected to bring so much more to the table, besides the "point defence" or "interceptor" role of Mig21, just like rafale is bringing so much more to the table ,

so its aerodynamics was built on Relaxed Static Stability all digital , flybywire software based computer controlled flight like the Euro canards,

and Tejas is not just multi role, It is "swing role" or "omni role" like rafale,

no other fighter in IAF has this capability,

for some fun , try googling to know the difference between two,

 

[ersakthivel]

Thanks Shri. Sakthivel. I have already mentioned that Tejas is currently multi-role. But my doubt was regarding the motivation towards the choice of the current wing design at the time of its conceptualization when Tejas was envisaged to perform the role of Mig-21. And this has been well explained by Bleh & SwordofDarkness

if you want to know more about comparison and technical aspects of tejas ,

some blat from the past.

its heavy reading . and heated arguments,

DOnt say I didnt warn you

Combat Aircraft technology and Evolution

And MAKS videos as well: www.youtube.com/watch?v=KpLTrNoNVOM

defenceforumindia.com

And this,,,,,

Combat Aircraft technology and Evolution

Re: ADA LCA Tejas - IV This is best for you level .. It is better you keep off bumping upon the unknown .. Yes, Tejas is a great tribute to the planes of the sixties like Mirage III or Mig-21. It is the aviation equivalent of Mini or Fiat 500. Great thinking from Indians to use nostalgy...

defenceforumindia.com

 

[ersakthivel]

for folks who complain about drag in tejas,

this F16 Vs F16 XL article is a good read,

which explains the all crucial high G onset rate of double deltas (cranked delta in tejas) , which holds the key in modern close combat specs

The Revolutionary Evolution of the F-16XL | Air & Space Forces Magazine

This dual role fighter candidate has one foot in the present ad one foot in the future.

www.airforcemag.com

from the article above

"
Importance of High Turn Rate

For a decade and a half, many fighter tacticians have stressed the paramount importance of being able to sustain a high turn rate at high Gs.

The rationale was that with such a capability, enemy aircraft that cannot equal or better the sustained turn rate at high Gs could not get off a killing shot with guns or missiles.

With developments in missiles that can engage at all aspects, and as a result of having evaluated Israeli successes in combat, the tacticians are now leaning toward the driving need for quick, high-G turns to get a “first-shot, quick-kill” capability before the adversary is able to launch his missiles.

This the F-16XL can do. Harry Hillaker says it can attain five Gs in 0.8 seconds, on the way to nine Gs in just a bit more time. That’s half the time required for the F-16A, which in turn is less than half the time required for the F-4. The speed loss to achieve five Gs is likewise half that of the F-16A.

All of these apparent miracles seem to violate the laws of aerodynamics by achieving greater range, payload, maneuverability, and survivability. Instead, they are achieved by inspired design, much wind-tunnel testing of shapes, exploitation of advanced technologies, and freedom from the normal contract constraints.

The inspired design mates a “cranked-arrow” wing to a fifty-six inch longer fuselage.

The cranked-arrow design retains the advantages of delta wings for high-speed flight, but overcomes all of the disadvantages by having its aft portion less highly swept than the forward section. It thus retains excellent low-speed characteristics and minimizes the trim drag penalties of a tailless delta.

Although the wing area is more than double that of the standard F-16 (633square feet vs. 300 square feet), the drag is actually reduced.

The skin friction drag that is a function of the increased wetted (skin surface) area is increased,

but the other components of drag (wave, interference, and trim) that are a function of the configuration shape and arrangement are lower so that the “clean airplane” drag is slightly lower during level flight

, and forty percent lower when bombs and missiles are added.

And although the thrust-to-weight (T/W) ratio is lower due to the increased weight, the excess thrust is greater because the drag is lower – and excess thrust is what counts.

The larger yet more efficient wing provides a larger area for external stores carriage. At the same time, the wing’s internal volume and the lengthened fuselage enable the XL to carry more than eighty percent more fuel internally. That permits an advantageous trade off between weapons carried and external fuel tanks."

F-16 Designer Harry Hillaker | Code One Magazine

Interview with Harry Hillaker, chief designer of the F-16.

www.codeonemagazine.com

 

[Raj Malhotra]

I wrote a 20 page article one year back and posted on DFI. Using studies from F-16XL the aerodynamic drag for Delta wing is lesser compared to conventional swept back wing even though area of Delta is larger. Hence LCA has very good acceleration and range. It’s payload range matrix is better than Jaguar and almost near Mirage 2000

 

[Pazhassiraja]

if you want to know more about comparison and technical aspects of tejas ,

some blat from the past.

its heavy reading . and heated arguments,

DOnt say I didnt warn you

Combat Aircraft technology and Evolution

And MAKS videos as well: www.youtube.com/watch?v=KpLTrNoNVOM

defenceforumindia.com

And this,,,,,

Combat Aircraft technology and Evolution

Re: ADA LCA Tejas - IV This is best for you level .. It is better you keep off bumping upon the unknown .. Yes, Tejas is a great tribute to the planes of the sixties like Mirage III or Mig-21. It is the aviation equivalent of Mini or Fiat 500. Great thinking from Indians to use nostalgy...

defenceforumindia.com

Thank you..