LCA TEJAS MK1 & MK1A: News and Discussion

[patriots]

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[Advaidhya Tiwari]

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Excellent news. It was clear from the outset that F414 with 98kN was over 10% short of required thrust. If he has to say this, the project has already started but not made public yet

 

[patriots]

Excellent news. It was clear from the outset that F414 with 98kN was over 10% short of required thrust. If he has to say this, the project has already started but not made public yet

Not started yet.....I think.........New engine s required for amca....lsp.......

 

[Advaidhya Tiwari]

Not started yet.....I think.........New engine s required for amca....lsp.......

DRDO rarely announces anything without the project beginning. Moreover it already has been decided that AMCA & MWF will be powered by 110kN engine over 2 years back as seen by their finalised design. So, by all means, the engine project has started. It is likely to take 2025-7 for it to be ready.

 

[Enquirer]

Excellent news. It was clear from the outset that F414 with 98kN was over 10% short of required thrust. If he has to say this, the project has already started but not made public yet

Dude! He's talking about AMCA, not Tejas Mk2

 

[Jackd]

Dude! He's talking about AMCA, not Tejas Mk2

For some reason he keeps saying that the new 110kn engine will be for AMCA and MWF whereas it is clear that GE 414 will be the engine for MWF as has been made pretty clear by all the parties involved.

 

[Advaidhya Tiwari]

Dude! He's talking about AMCA, not Tejas Mk2

For some reason he keeps saying that the new 110kn engine will be for AMCA and MWF whereas it is clear that GE 414 will be the engine for MWF as has been made pretty clear by all the parties involved.

I am saying that MWF & AMCA will use same engine. Both will use F414 initially for testing. But eventually, it will be indigenous 110kN engine for both.

 

[HariPrasad-1]

Continued ..

The initial road to the Mk2
However, to meet the IAF’s stringent air staff qualitative requirements (ASQR) for the LCA project, ADA knew that substantial changes to the basic Mk1/Mk1A airframe were required and that is where the genesis of the Tejas Mk2 development program lies. There were two primary concerns: the IAF wanted a fighter that had faster transonic acceleration and a higher STR of about 18 degrees per second. As late as Aero India 2017, ADA displayed scale models that aimed to achieve this by extending the Mk1 with a 0.5 m fuselage plug and fitting a more powerful F414 engine with a maximum rated thrust of 98kN. The plug was to be inserted just behind the canopy where the area curve had the highest discontinuity (see Area curve in Figure 2). In addition to the plug, ADA studied a bulged canopy to improve area ruling even further. The combined effect was 6 percent lower supersonic drag, which in turn led to a 20 percent improvement in transonic acceleration and 2 percent improvement in maximum speed [4]. The fuselage plug and bulged spine would also provide space for more internal fuel and LRUs.

Figure 2: Canopy optimization study shows a bulged canopy improving the area ruling results in 6% reduction in drag, 20% increase in transonic acceleration and 2% increase in max speed[4].

Similarly, it was observed that there was a sudden kink in the aft bottom of the fuselage in Mk1 as shown in Figure 3. By eliminating this kink and identifying an optimized smoothened aft fuselage, an improvement of 4.9 percent was predicted in the supersonic drag on the aft body region.

Figure 3: Assessment of aft body optimization for supersonic drag reduction. Comparison of Surface Cp contours near the aft region for base configuration and that of optimized aft region at M=1.2, AoA= 3 [cite].

Besides clean configurations, studies were also conducted to decrease the drag of loaded configurations. For example, it was realized early that by replacing the current ‘blunt’ pylons on Mk1 with more aerodynamically shaped pylons, significant drag reduction could be affected in supersonic regimes[18]. Figure 4 shows the inboard pylons before and after the reshaping. These new pylons have already been realized and are expected to even become a part of the MK1/1A platforms. One such pylon for the center fuselage has been put on display in Aero India 2019.

Figure 4: wing inboard pylon: before and after reshaping for better supersonic drag [18].

Similarly, computation fluid dynamics (CFD) studies on a variety of drop tanks have yielded fuel tank geometries which could carry more fuel at marginal to no extra cost in drag. For example, Figure 5 shows the modified supersonic drop tank arrived by choosing optimal lengths for the conical nose and tail sections. The final shape allowed the carriage of 58 percent more fuel (710 L against the current 450 L) at only two counts greater supersonic drag. This provided a significant increase of about 11 percent in flight mission time. This tank can also be seen at Aero India 2019.

This is what \i have been advocating for a long time. Improve Aerodynamics first and reduce some weight. You can make even Mk1 a wonder. 20% increase in trans sonic regime is bloody a hell of an improvement. 6% drag and something similar reduction in weight will improve Tejas by a huge margin. In his simulation study of combat between LCA Tejas and F 16, Vivek Ahuja said that any reduction in Tejas Mk1 weight from current level will Improve itd edge over F 16 significantly. Just work on basics. Tejas Mk1 and Mk1 A can be top class fighters in their class much ahead of Bunder and Junk 10.

 

[Bleh]

F414 for mwf........a new engine for amca...........f414 will be used in td2 .and td1 of amca

I am saying that MWF & AMCA will use same engine. Both will use F414 initially for testing. But eventually, it will be indigenous 110kN engine for both.

For some reason he keeps saying that the new 110kn engine will be for AMCA and MWF whereas it is clear that GE 414 will be the engine for MWF as has been made pretty clear by all the parties involved.

Permanent or stop-gap, why was F414 (Weight: 1,110kg Thrust: 57.8kN-97.9kN) even chosen for Tejas Mark 2 over EJ200 (Weight: 990kg Thrust: 72kN-103kN)?

 

[patriots]

F414 for mwf........a new engine for amca...........f414 will be used in td2 .and td1 of amca

 

[Advaidhya Tiwari]

F414 for mwf........a new engine for amca...........f414 will be used in td2 .and td1 of amca

How does it make sense to use F414 in MWF when its MTOW is 17.5 ton? By what logic is 59/98kN enough for such MToW? Minimum dry thrust of 65kN & wet thrust of 105kN is needed even if we take some aerodynamic improvement (5-6%)

Permanent or stop-gap, why was F414 (Weight: 1,110kg Thrust: 57.8kN-97.9kN) even chosen for Tejas Mark 2 over EJ200 (Weight: 990kg Thrust: 72kN-103kN)?

EJ200 has 60/90 kN, not 72/103kN. Always note that the afterburner stage has at least 150% of dry stage. So, 72kN must have minimum of 108kN after burner thrust.

Reality is that EJ200 is still 60/90kN and F414 is 59/98kN. There has been no EPE or any other variant for either engine. There is no engine in the world that has 70/110 kN thrust and India will have to develop it on its own. In the stop gap engine, it is better to get that engine which is closest to 110kN wet thrust for better take off performance which is F414, not EJ200

 

[patriots]

https://www.tribuneindia.com/mobi/n...build-bigger-jets-says-drdo-chief/733937.html

After the final operational clearance (FOC) of Light Combat Aircraft Tejas, India is now looking at a rapid multi-pronged effort to build the next class of fighter jets having more powerful engines and potent weaponry.

Dr G Satheesh Reddy, who is Secretary, Defence Research and Development, and also Chairman of DRDO, said, “The FOC for Tejas is a landmark for the country. From here on, we can produce faster (jets).” The design for the Medium Weight Fighter (MWF) is ready. The prototype will be ready by 2021-end,” the senior defence scientist added.

The Tejas weighs 6.5 tonnes and the MWF is the next class and targeted to weigh around 17 tonnes. The Aeronautical Development Agency and the Indian Air Force (IAF) have designed it as per the requirement of the IAF. It will have an engine of 98 Kilonewton (Kn) thrust.

Also, India is looking to take a technological leap. The DRDO is now in talks with an international partner to make a jet engine of 110 Kn power. So far, no such engine exists anywhere in the world. “We are open to working on this and are in talks with partners for joint development,” said Dr Reddy, adding this engine could be used on future jets.

On being asked about the Kaveri engine, Dr Reddy said it would be used on UAVs. “It is not being shelved.” Notably, Kaveri’s thrust is about 75 Kn and 90 Kn is desired to power a fighter jet.

The Ministry of Defence has already informed Parliament about the technological difficulties of engine-making, including non-availability of raw material/critical components and skilled manpower.

On the much-debated construction timeline for the variants of Tejas, Dr Reddy, who took over as DRDO Chairman in August last year, said the first 20 of the Initial Operational Clearance (IOC) version will be ending very soon. The production of 20 jets under the FOC version would start this year and would be done in two years. We are waiting for the IAF to place an order for 83 jets of the Mark 1A version.

On the engine of the Arjun tank, so far imported from MTU Germany, Dr Reddy said, “A new engine is being developed and will be tested.”

 

[Bleh]

EJ200 has 60/90 kN, not 72/103kN. Always note that the afterburner stage has at least 150% of dry stage. So, 72kN must have minimum of 108kN after burner thrust.

Reality is that EJ200 is still 60/90kN and F414 is 59/98kN. There has been no EPE or any other variant for either engine.

Oh, ok. I just sourced Wiki............

 

[tsunami]

In Mk-2 wing span is increased from 8.2 meter to 8.5 Meter and length of the fighter is also increasing by 1.3 meters. So how is it possible that the wing area will remain same at 38.8 sq meters??

 

[Bleh]

In Mk-2 wing span is increased from 8.2 meter to 8.5 Meter and length of the fighter is also increasing by 1.3 meters. So how is it possible that the wing area will remain same at 38.8 sq meters??

Fuselage widened to make room for more fuel... wings shifted outwards.

 

[Immanuel]

F414 EPE will probably end up powering the AMCA. It's common sense, the GE engines have been ideal for Tejas, reliable and with plenty of growth options.

 

[Advaidhya Tiwari]

F414 EPE will probably end up powering the AMCA. It's common sense, the GE engines have been ideal for Tejas, reliable and with plenty of growth options.

There is no EPE engine. Simply don't invent things out of thin air. EPE engine is as real as BatMobile

 

[ersakthivel]

The problem here is that lift & drag are related. More lift also means more drag. So, there is one disadvantage of lower wing loading that maneuvering is difficult due to higher drag

Tail fins indeed provide lift. In naval variant, the tail fins help in adding lift at the rear and hence helping in lower landing speed without the plane crashing. Delta wings without tail has high landing speeds which is a problem on aircraft carrier.

looking at absolute drag or absolute lift is meaningless ,

Its the lift to drag ratio,

if wing area produces higher lift than the induced drag, then it is mostly beneficial.

canards are now feasible because we have GE 414 available & ASR for empty weight has gone above 7 tons , allowing longer fuselage.

In mk1 with tight 5.5 ton empty weight reducing fuselage length , earlier wind tunnel tests proved canards gave only marginal lift , not wort the FCS complexities & weight penalties.

So they were not included in mk1.

To give lift canard cross section must be in aerofoil form, otherwise its contribution to lift comes from ,"energizing vortex flow over wing"

two little canards dont provide excess lift to increase MTOW to 17 tons, Not possible, Its the higher powered engine that does the job.

 

[proud_indian]

HAL's Supersonic Omni Role Trainer Aircraft (SPORT) Simulator Lead-In Fighter Training (LIFT) is the vital link for fighter pilots between basic flight school and primary weapon system training.

HAL is keen to launch the ndignous development of SPORT with 4++ generation or equivalent capabilities to bridge the gap in pilot training to command front line fighters.

The SPORT aircraft will be utilized for fighter training after Advanced Jet Training stage and before induction into a frontline fighter squadron.

"SPORT" to provide: -
Dedicated large force engagement
Group combat training
-Concepts and training on tactical and operational level Net Centric Warfare )NCW)
-Fire control radar (FCR) concepts and operations training
-Infra-red search and track (IRST) concept & operations training
-Helmet mounted display system (HMDS) concepts & operations training
-Dedicated BVR combat training
-Dedicated EW concepts and training
-Laser environment concepts and training on use of Laser Designator Pods (LDP)
- Air to air missile launch exposure (BVR and CCM)
-ALCM, ASM launch exposure
-PGM launch practice (with and without target designation by mother aircraft)

Must Watch, Don't miss it!

 

[Shashwat]

LSP2 flew- not sure whether this is cause of #AeroIndia2019 or with the new Uttam radar "ON". Check the ada page..