ADA Tejas (LCA) News and Discussions

[sayareakd]

you can see how this has evolved from Tech demo to limited serial production

 

[sayareakd]

mind it

 

[shuvo@y2k10]

how long will it take for hal to manufacture 200 tejas aircrafts?

 

[sayareakd]

how long will it take for hal to manufacture 200 tejas aircrafts?

in war 1 year and in peace time 16 is max per year, So you can figure out.

 

[happy]

Introducing Tejas: India's First Home-Grown Supersonic Fighter Jet - India Real Time - WSJ

India's air force is set to receive the country's first locally-designed and developed supersonic fighter jet, the Tejas, in a significant milestone for its aerospace industry as it tries to phase out the aging and accident-prone MiG-21 jet fleet.

State-run Hindustan Aeronautics Ltd. plans initially to produce eight of the single-engine multi-role fighter jets a year from 2014, and to double production rate at a later stage after consultations with the air force and the defense ministry, R. K. Tyagi, chairman of Hindustan Aeronautics said Thursday.

Conceived in 1983 as the Light Combat Aircraft program, the project to develop the Tejas was delayed for several years because of difficulties related to developing the jet from scratch, which resulted in an escalation in the cost. The aircraft has been designed and developed by the Aeronautical Development Agency among other government agencies with Hindustan Aeronautics as the principal partner. It has a digital fly-by-wire flight control system and composites were used extensively to develop its airframe to provide strength and offer lower radar visibility.

The aircraft—which is powered by a General Electric Co. engine– received the first so-called initial operational clearance from the Indian government in Jan. 2011. The second initial operational clearance –which means the fighter is ready to operate in all conditions–was awarded on Friday, paving the way for its series production by Hindustan Aeronautics and induction into the fleet of the air force, according to the company. The Tejas will not be combat-ready until 2015 when it receives its final operational clearance—which would involve the integration of weapon systems and air-to-air refueling.

 

[makmohan]

Tejas in camo // :thumb:

 

[Shaitan]

 

[ersakthivel]

Must be be the year wise flight testing graph showing 500 plus test flights this year alone.

 

[ersakthivel]

THE so called superiority of canard delta like Grippen over Tejas which we come across quite often in many forums,Recently I came across the same passage in a namesake forum where some researcher explained as below,

Close-coupled canards help lift when turning, which means that aircraft can achieve higher turn rate; they also help controllability by allowing control surfaces to be effective even at very high angles of attack, and improving wing response to any control surface inputs. However, since they cannot be in same plane as wing, they increase drag in level flight, and make it harder to optimize aircraft for RCS reduction (they tend to move during flight, and gap between canard and hull must be covered with something to reduce RCS).

Increased drag means less range; also, without canards, wing can be extended further forward, which does not really help maneuverability (any improvement in lift-to-weight ratio due to lower wing loading is offset by far earlier stall onset and reduced controls surface responsiveness, which is especially a problem since transient performance is actually more important than maximum turn rates; plus larger wing means more drag for any given angle of attack) but lower wing loading can well mean larger payload, and larger wing also has more volume for fuel.

But the explanation in bolded parts suits simple deltas like Mirage-2000, not compound or cranked delta like Tejas,

Why?

In canard deltas the canards create lift inducing vortex that cling on to the wing upper surface to delay boundary separation and avoid early onset of stall, helping canard deltas to maintain a high turning rate and making them controlable at high AOA,

In cranked or compound deltas like Tejas same vortice generation job is done by the lesser swift part of the wing leading edge near the wing root which do the same job-"create lift inducing vortex that cling on to the wing upper surface to delay boundary separation and avoid early onset of stall, helping canard deltas to maintain a high turning rate and making them controlable at high AOA,"

Why testes a canard delta model for tejas vs a cranked delta model in wind tunnel and discarded canard delta as it gave no noticeable improvement for the drag and weigh penalty they imposed for a small fighter like tejas,

So they went for cranked delta like F-16 XL, with LEVCONS for naval versions to assist carrier landing,

http://www.airforcemag.com/MagazineArchive/Pages/1983/November 1983/1183f16xl.aspx

Hillaker said that the objective of the F-16XL program was to achieve a logical evolution from the basic F-16 that would provide significant improvements in all mission performance elements. At the same time, it would retain the fundamental F-16 advantage of low procurement and operating costs.

F-16 is a cropped delta with no canards and its next evolution was a cranked delta F-16XL,

To say that Hillaker's design team achieved its objectives is an understatement. Example: For an air-to-surface mission, the F-16XL can carry twice the payload of the F-16A up to forty-four percent farther, and do it without external fuel tanks while carrying four AMRAAM (Advanced Medium-Range Air-to-Air Missiles) and two Sidewinder AIM-9 infrared missiles.

With equal payload/weapons and external fuel, the mission radius can be nearly doubled. When configured for a pure air-to-air mission, an F-6XL with four AMRAAMs and two AIM-9s can go forty-five percent farther than an F-16A and can do so while conducting a combat action that is equal to thirty percent of its internal fuel.


As for penetration and survivability, the F-16XL can dash supersonically with a load of bombs at either high or low altitude. It can climb at high rates with the bombs aboard. And it has a speed advantage of up to eighty-three knots over the F-16A at sea level at military power setting and 311 knots on afterburner at altitude while carrying a bomb load.


Two additional capabilities of the F-16XL contribute to survivability. First is improved instantaneous maneuver ability coupled with greatly expanded flight operating limits (with bombs), and second is reduced radar signature resulting from the configuration shaping.

All this is the result of cranked delta design, which is followed in Tejas and conveniently omitted by people criticizing it,

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.

The following passage explains the advantage of cranked or compound delta over any other wing form,

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 tradeoff between weapons carried and external fuel tanks.


Through cooperation with NASA, more than 3,600 hours of wind-tunnel testing refined the shapes that Harry Hillaker and his designers conceived. More than 150 shapes were tried, with the optimum design now flying on the two aircraft at Edwards.

So without the tail and canard surfaces F-16 XL wins over F-16 in all parameters even when having a huge wing which people often misunderstand to be drag prone, as explained in the passage below, it is not always the case.

Because as explained in the site itself-"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."

Of particular interest were the control surfaces on the aft edge of the cranked-arrow wing. The F-16XL does not have a horizontal tail.

Thus, the control surfaces for both pitch and roll are on the rear edge of the wing. The inboard surfaces are mainly for pitch control, while the out board surfaces take care of roll control.

However, thanks to the automatic flight control system, when performance requires it, all four surfaces can act in either pitch or roll.

So with just 20 percent increase in cost " the F-16XL has the advantage of double the range or payload of the current impressive F-16 performance."

With the F-16XL, the US Air Force has the option to gain markedly improved range, payload, and survivability performance over current fighters. According to its designers, the F-16XL in production would have a unit flyaway cost of about fifteen to twenty percent more than the F-16C and D.

This I have already posted many times here,So despite having lower TWR than F-16 or Mig-29The tejas won't suffer that much in close combat performance because as mentioned in the article it is excess thrust that counts,

Once full FOC parameters are out a year from now we can know all the details,

 

[ersakthivel]

So despite having lower TWR than F-16 or Mig-29The tejas won't suffer that much in close combat performance because as mentioned in the article it is excess thrust that counts,
The Revolutionary Evolution of the F-16XL

"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."

So posting the above discarded Tejas model with canards and saying the words below is actually far from truth,

Pity they didn't go with that configuration... looks like they decided to screw its air-to-air capabilities for sake of strike.

With no canards SU-35 does far better than canarded SU-30s and no american fighter makers has put a canard in any of their successful designs,

Fighter design is a sum of all parts according to the total design philosophy.

Some chose canard delta as grippen, TYPHOON and RAFALE (all of them have very different implementation of canards between themselves, and it itself is a separate topic of a deep technical discussion!!!!!!. The french say that canards onRAFALE are simply for stability in their website.)

and many others did not choose it,
So taking one aspect apart and continue to spread lies is not going to wash.

 

[ersakthivel]

Delta / Canard fighter layout; why?, page 1
Delta / Canard fighter layout; why?, page 1
Can read more in links above ,

 

[Neil]

 

[happy]

This I have already posted many times here,So despite having lower TWR than F-16 or Mig-29The tejas won't suffer that much in close combat performance because as mentioned in the article it is excess thrust that counts,

Once full FOC parameters are out a year from now we can know all the details,

Can you please explain what is excess thrust ??

 

[ersakthivel]

Can you please explain what is excess thrust ??

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."



Engine produces a fixed amount of thrust,

A part of the thrust is required to overcome the drag,

Remaining part of the thrust ,"effective thrust or excess thrust" is used for flight of the plane,

Due to low overall drag (which is a sum of three component drags ---wave+skin+interferance) much higher thrust is availablle for the plane to turn or roll or fly at a higher speed or fly farther.


Even though surface skin drag is high due to excess wing area of the large low wing loading wing, other components of drag like interferance and wave drag is reduced.

SO total air plane drag which is a sum of these three components of drag(skin, wave, interferance) is lower,

So Engine thrust-thrust required to overcome the air plane drag which is the effective thrust available for flight is higher for large wing loading cranked deltas like F-16XL and tejas,

 

[happy]

Even though surface skin drag is high due to excess wing area of the large low wing loading wing, other components of drag like interferance and wave drag is reduced.

SO total air plane drag which is a sum of these three components of drag(skin, wave, interferance) is lower,

So Engine thrust-thrust required to overcome the air plane drag which is the effective thrust available for flight is higher for large wing loading cranked deltas like F-16XL and tejas,

So, excess thrust is what remains after the required thrust to overcome drag is utilized ?? Am I right ??

 

[ersakthivel]

So, excess thrust is what remains after the required thrust to overcome drag is utilized ?? Am I right ??

Engine produces a fixed amount of thrust,

A part of the thrust is required to overcome the drag,

Remaining part of the thrust ,"effective thrust or excess thrust" is used for flight of the plane,

Due to low overall drag (which is a sum of three component drags ---wave+skin+interferance) much higher thrust is availablle for the plane to turn or roll or fly at a higher speed or fly farther.


Even though surface skin drag is high due to excess wing area of the large low wing loading wing, other components of drag like interferance and wave drag is reduced.

SO total air plane drag which is a sum of these three components of drag(skin, wave, interferance) is lower,

So Engine thrust-thrust required to overcome the air plane drag which is the" excess thrust or effective thrust "available for flight is higher for large wing loading cranked deltas like F-16XL and tejas,

because the cranked delta shaping inferior in wetted area drag or skin surface area drag,

it is superior when it comes the other two components of drag namely , wave and interference drag

So when it comes to the all crucial lift to drag ratio which determines the aerodynamic efficiency of the plane it gets a higher ratio.

Also the vortex generated by the craned delta reduces pressure over the upper wing surface in high AOA flight profile , which further adds to the better handling of cranked deltas in high AOA regimes,

The canards also do the same job , besides doing the job of another control surface, But if you watch the canard delta planes wing attached control surfaces it is very small compared to tejas wing attached control surfaces.

because the canards in canard deltas take over a portion of the load.so they are small

yes as explained in the f-16 xl site,

 

[ersakthivel]

That is incorrect. LCAs strike requirement happened well after LCA started flying. The early specifications never asked for a strike fighter. It was only meant to carry dumb bombs and A2A missiles.

As for why canards were not used, LCA wasn't designed for high maneuverability like Gripen was. I don't believe LCA can turn faster than Mirage-2000 in sustained. It was meant for high ITR, high climb rates and high acceleration and employment of BVR weapons like Mig-21 Bison. So, for the specs that IAF asked for, LCA didn't need canards. Only the twist of the root was enough to achieve requirements.

Meaning LCA can't afford to get into a turning fight like the Eurocanards, that's not any different from Mig-21 Bison either. Mig-21 Bison is used in IAF for spot interception and escort plus a bit of air interdiction. Nothing else. LCA won't do much of anything else apart from that.

Well the same stupid stuff from the namesake forum again. i don't know what these guys smoke to sprout BS like this,

No hope for these guys,

IAF gave an initial STR of 17 deg to tejas which is just a degree less than F-16 A, B.


and a TWR of more than1 (which is ten percent more than TWR of even the upgraded Mirage-2000 of today.) from the start itself,

tejas has a higher wing area than Mirage-2000 compared to the weight they both carry, lower wing loading than Mirage-200, What is the purpose, I just used the F-16 Xl analogy and explained it clearly what a low wing loading crank delta means a true multi role fighter designed to excel in both roles air to air and air to ground,

Why did IAF include HMDS enabled high off bore sight deadly cclose combat missiles which are not even there in RAFALE now and not present in grippen C, D when they were introduced?

IAF gave the second biggest radar range requirement for tejas for what purpose?

in the just concluded IORNFIST tejas dropped PGMs and fired two R-73 close combat WVR missiles with in a hundred seconds and dropped all its external stores in one go to get ready for turning fight, So what else it is supposed to do more?


with AOA opened to 24 deg till today and set to go beyond even the FOC limit of 28 deg,

as per the statement of the most experienced tejas test pilot Suneet krishna who was awarded the best test pilot of the year award in US,

why the heck these guys call it a Mig-21 like interceptor which can't turn and fight like mirage-2000?

tejas was designed as multi role from the start , otherwise why did IAF ask for a 4 ton weapon load with a multi mode radar with precision ground attack mode along with anti ship missiles and a naval version for carrier?

Grow up guys,if you can't digest at least shut up.

or

you can go to the bathroom and cry alone.

 

[CuriousBen]

I was going through the interview of Mr Avinash Chander with Mr Ajai Shukla and its clear the FOC cant happen before end of 2014.
Is there any way that FOC can be speeded up ?
For IOC how many hours of flight testing will be required ? Will FOC also mean that the LCA trainer and LCA navy both will be ready ?



The other news in Ajai Shukla's blog was about SITARA IJT. It was heartening to know that its ioc is also few weeks away !
Now, will HTT 40 be shunted away or HAL take it unto themselves as a challenge to get it flying ?

I am keen to see the LCA navy platform emerging sperbly successful. However there seem to be less test happening . Is there anything wrong ?

 

[arnabmit]

Don't know if posted earlier:

[pdf]https://www.ada.gov.in/images/IOC%20content/ADA-%20Tejas%20Brochure%20Final.pdf[/pdf]

 

[ersakthivel]

Can someone tell what all is included in the take off weight in comparison to empty weight apart from fuel?

Bharat Rakshak "¢ View topic - LCA News and Discussions, 22-Oct-2013

A detailed analysis of weight with photo by Indranilroy in the BR link above.

He concludes the weight of external stores to be 3.5 ton or 4 ton.

And appolyn's post in DFI thread sheds some light on it,

http://defenceforumindia.com/forum/indian-navy/45110-navy-orders-8-tejas-fighter-jets-3.html

Tejas - Specifications - Leading Particulars and Performance

Loaded weight weight = Empty Weight + Internal Fuel + Ammunition = 9500Kg
Max Take-off weight = Loaded Weight + External Stores (Fuel Tank +/or AAM +/or SOM +/or Bombs ~ 3700Kg)

So external stores on Tejas can weigh max 3.7 tons, but the preferred configuration will (?) be one centerline fuel tank + AAM (Derby + Python)

http://defenceforumindia.com/forum/indian-navy/45110-navy-orders-8-tejas-fighter-jets-5.html

The following poster in aeroindia-2013 from ADA says tejas has already reached mach 1.6 at high altitudes.

It clearly mentions the word ,"reached mach 1.6 at ceiling altitude", even though in IOC-2 it is certified for mach 1.4.

It also mentions external store weight of 3.5 tons, excluding the weight of two R-73 WVR missiles along with the weight of 7 pylons,

because as per ADA norms the "the weight of two R-73 WVR missiles along with the weight of 7 pylons" is always included in take off clean weight figure of 9800kgs.It may include the weight of 300 Kg telemetry equipments also.

But HAL says take off clean as 9500 Kg. may be as per HAL take off clean norms---'"the weight of two R-73 WVR missiles along with the weight of 7 pylons," which will come close to 300 Kg is not included.

So with take off clean 9.5 or 9.8 tons and MTOW of 13.2 tons we have somewhere around 3.7 ton external weapon weight on tejas