LCA Tejas Mk1 & Mk1A - News and discussions

[suryakiran]

I think you are underestimating the Indian aerospace industry quite a bit. And I don't believe the J-10C will have any real advantage in both BVR and WVR against LCA Mk1A. PLAAF needs a J-10D.

He is assuming that numbers make up any air battle. The regime it functions and what is supposed to do is neatly ignored. The LCA needs to get off the ground quickly, take the shot and come back as far as Mk1 goes. Not to mention keeping it flying during high tempo ops.

 

[randomradio]

He is assuming that numbers make up any air battle. The regime it functions and what is supposed to do is neatly ignored. The LCA needs to get off the ground quickly, take the shot and come back as far as Mk1 goes. Not to mention keeping it flying during high tempo ops.

Yep, that's what's it made for.

It's specifically been made to operate in the mountains and at higher altitudes, that wing loading gives it away. Better climb rate and cruise performance is a given from 4000m altitude when compared to the J-10's sea level figures.

But the real advantage lies in serviceability and turnaround time. We may see a 30-40% boost in just general availability because of that, which means given equal numbers, the Chinese will have to take out 30-40% of our LCAs with no losses on their side just to match our numbers. But the minute we bring in our shorter distance to the frontline versus their longer distances and lower op tempo, our sortie generation rate can become 2-3 times theirs, which means adding to the 30-40% advantage, they will need at least 3-4 times more J-10s to compete.

Gripen E (LCA Mk2) with the F414 will see even bigger advantages, hence all the praise from the Chinese.

 

[Saaho]

It seems that most Indians do not understand what I mean, the Tejas is a tailless delta-wing aircraFt, this aircraFt itselF has poor subsonic perFormance, Its main advantage is supersonic, so the Mirage 2000 has a maximum speed oF Mach 2.2, The F 106 has a maximum oF Mach 2.3, why is the Tejas only Mach 1.6, I think it was a sharp drop in the eFFiciency oF his inlet at supersonic speeds, a sharp drop in the thrust oF his engine, The decrease in engine thrust directly leads to a decrease in maneuverability at supersonic speeds

Now I am not that much of aeronautical engineer, my main focus has always been electronics and sensors. I believe @vstol Jockey can address, this much better.

That being said, thurst to weight ratio of Mirage-2000 for all of its variants has never been more than 0.9. Tejas has 1.07. Neither have DSI intake. So, how come Tejas has less manuverability as compared to Mirage-2000 on account of non-DSI intake while Tejas has more thrust in relation to its size?

That does not make sense at all. I highly doubt that Indian designers could not design an intake for the supersonic flight regime that is required for F404-IN6.

I think the folly of @lx111 here is to assume that DSI is the only solution for supersonic intake. Fighter jets have been flying (with Delta wings no less) with non DSI intakes for decades. In engineering, there are many solutions for same problem.

 

[vstol Jockey]

@lx111, the speed restriction for Tejas is on account of fixed air intakes. It does not have movable cone in the inlet like Mirage-2000 and so its speed is restricted to 1.6Mach. Check your own J-20 and tell me why it is restricted to Mach 1.8 only?

 

[LX1111]

@lx111, the speed restriction for Tejas is on account of fixed air intakes. It does not have movable cone in the inlet like Mirage-2000 and so its speed is restricted to 1.6Mach. Check your own J-20 and tell me why it is restricted to Mach 1.8 only?

That does not make sense at all. I highly doubt that Indian designers could not design an intake for the supersonic flight regime that is required for F404-IN6.

I think the folly of @lx111 here is to assume that DSI is the only solution for supersonic intake. Fighter jets have been flying (with Delta wings no less) with non DSI intakes for decades. In engineering, there are many solutions for same problem.

I never said the only solution for dsi itself to mentor a modern fighter, Any fighter that focuses on supersonic flight not uses a fixed inlet, which reduces its efficiency dramatically at supersonic speeds. Of course you can use other inlet, the best inlet is of course the f 15 inlet,Four-wave supersonic inlet with adjustable external pressure，

Or you can use the CARET Inlet like the FA-18E/F

The FA-18 used the same stationary inlet as the Indians
But let's not forget that the FA18 is a fighter that focuses on subsonic performance over supersonic performance

 

[LX1111]

@lx111, the speed restriction for Tejas is on account of fixed air intakes. It does not have movable cone in the inlet like Mirage-2000 and so its speed is restricted to 1.6Mach. Check your own J-20 and tell me why it is restricted to Mach 1.8 only?

I've never heard of the J-20 flying at a top speed of Mach 1.8, and even the most conservative estimate is Mach 2.0. Its actual flight speed may be higher
Even if we don't look at fourth-generation aircraft, second-generation aircraft like the MiG-21, they use a fixed inlet, But this intake cone is still suitable for the supersonic phase, so you see that the MIG21 is a good supersonic performance and subsonic performance is not good

 

[LX1111]

Now I am not that much of aeronautical engineer, my main focus has always been electronics and sensors. I believe @vstol Jockey can address, this much better.

That being said, thurst to weight ratio of Mirage-2000 for all of its variants has never been more than 0.9. Tejas has 1.07. Neither have DSI intake. So, how come Tejas has less manuverability as compared to Mirage-2000 on account of non-DSI intake while Tejas has more thrust in relation to its size?

That does not make sense at all. I highly doubt that Indian designers could not design an intake for the supersonic flight regime that is required for F404-IN6.

I think the folly of @lx111 here is to assume that DSI is the only solution for supersonic intake. Fighter jets have been flying (with Delta wings no less) with non DSI intakes for decades. In engineering, there are many solutions for same problem.

@lx111, the speed restriction for Tejas is on account of fixed air intakes. It does not have movable cone in the inlet like Mirage-2000 and so its speed is restricted to 1.6Mach. Check your own J-20 and tell me why it is restricted to Mach 1.8 only?

So you know so little about aviation, I'll simply give the Indians a piece of advice so that they don't get caught up in the excitement of useless nationalism

In supersonic inlet design, there are four stages, one of which is the intake cone

This stage is represented by the MiG 21 and the F104

So you know so little about aviation, I'll simply give the Indians a piece of advice so that they don't get caught up in the excitement of useless nationalism

In supersonic inlet design, there are four stages, one of which is the intake cone

This stage is represented by the MiG 21 and the F104

The second stage is the adjustable baffle inlet, which is used in most third-generation fighters, represented by the MiG 23 and f 4

From the inlet to further development, it becomes CARET
The inlet uses the high-speed WaveRider theory, which creates an oblique shock wave from the leading edge under the wedge-shaped wing at high speed. After passing through this oblique shock wave, the air will form a high pressure region with uniform pressure. Based on the WaveRider theory, an inclined plate is arranged on the upper Wall and the inner Wall of the inlet to generate two oblique shock waves. Allows the high - speed air flow to be uniform after deceleration and pressurization through the wave surface,

The DSI inlet is based on the CARET for further structural simplification. Using a supercomputer to simulate complex hydrodynamics, a smooth curved bulge shape is obtained. By adding the bulge to the air inlet, This drum must be with the intake lip, play the role of boundary layer partition. The forward swept intake lip forms a high pressure area in the center, a low pressure area on both sides, and the lowest pressure at the junction with the fuselage. The bulge changes the flow direction and flows in the direction away from the inlet. When it approaches the inlet, it is squeezed by the central high-pressure air flow and completely squeezed out of the inlet. In this way, the intake port does not have to leave a certain distance from the fuselage, and the intake efficiency is increased. In addition, the bulge also acts as a pre-compression, similar to the oblique shock generated by the partition, but without the action cylinder mechanism of the partition. The weight and cost of the structure are greatly reduced. However, the total pressure recovery coefficient of this inlet is slightly lower than that of the CARET inlet.

Next I answer the simplest question, which I guess most Indians here don't know, Why is a supersonic inlet different from a subsonic inlet? We all know that the higher the air velocity, the lower the pressure,
Overflow to the engine air speed is too high, then the air pressure will be too low, will lead to engine blade stall, leading to engine failure shutdown
So all the various inlets that we see are designed to compress and decelerate supersonic gas, the pressure increases, which capability determines the efficiency of the inlet

 

[vstol Jockey]

I've never heard of the J-20 flying at a top speed of Mach 1.8, and even the most conservative estimate is Mach 2.0. Its actual flight speed may be higher
Even if we don't look at fourth-generation aircraft, second-generation aircraft like the MiG-21, they use a fixed inlet, But this intake cone is still suitable for the supersonic phase, so you see that the MIG21 is a good supersonic performance and subsonic performance is not good
View attachment 32930

Are you trying to fool an Indian who has flown fighters including Sea Harriers and fully ops from Deck of a carrier by day and night? Think again?

 

[Rajput Lion]

So you know so little about aviation, I'll simply give the Indians a piece of advice so that they don't get caught up in the excitement of useless nationalism

Yeah @vstol Jockey, a former Indian Navy Sea Harrier fighter pilot knows so little about aviation while you are whole aviation encyclopedia

I told you not to go ahead and make a fool of yourself but didn't pay heed, did you and now you look like one

 

[Valhalla]

Here's an explanation posted to I D R W, which has since been removed..


Wayback link -> https://web.archive.org/web/20210625004304/https://id rw.org/test-pilots-explains-why-pilots-are-not-cleared-to-fly-above-1-6mach-on-lca-tejas/. (Remove whitespace between id rw)

Thakur explains that simple pitot type intake design used on LCA-Tejas is what prevents LCA-Tejas to have engineered speed of 2.0M while to achieve this speeds, LCA air intakes could have to re-done and also employ intakes cones as seen in Mirage-2000 and Mig-21 which moves move in or out of the intakes to maintain the shockwave in its the proper position, ahead of the first stage of the engine and need to be adjusted by the pilot.

Lack of intakes cones in LCA-Tejas means a hassle-free operation for the Pitot but this new phenomenon is not limited to LCA-Tejas alone but many are countries are now limiting Mach speed on many modern fighter jets after intense study and data collected over the years of the max speed at different attitudes as pointed by Thakur, who gives an example how below 22000 feet altitude Mach speed over 1.6 is not possible and a plane flying at Mach 1.8 has the advantage of only 60knot when it is above 28000 feet altitude.

 

[randomradio]

So you know so little about aviation, I'll simply give the Indians a piece of advice so that they don't get caught up in the excitement of useless nationalism

You are talking to a guy who designs fighter jets.

In supersonic inlet design, there are four stages, one of which is the intake cone
View attachment 32931

View attachment 32932

View attachment 32933
This stage is represented by the MiG 21 and the F104


The second stage is the adjustable baffle inlet, which is used in most third-generation fighters, represented by the MiG 23 and f 4
View attachment 32934

View attachment 32935

From the inlet to further development, it becomes CARET
The inlet uses the high-speed WaveRider theory, which creates an oblique shock wave from the leading edge under the wedge-shaped wing at high speed. After passing through this oblique shock wave, the air will form a high pressure region with uniform pressure. Based on the WaveRider theory, an inclined plate is arranged on the upper Wall and the inner Wall of the inlet to generate two oblique shock waves. Allows the high - speed air flow to be uniform after deceleration and pressurization through the wave surface,

View attachment 32936
View attachment 32937

The DSI inlet is based on the CARET for further structural simplification. Using a supercomputer to simulate complex hydrodynamics, a smooth curved bulge shape is obtained. By adding the bulge to the air inlet, This drum must be with the intake lip, play the role of boundary layer partition. The forward swept intake lip forms a high pressure area in the center, a low pressure area on both sides, and the lowest pressure at the junction with the fuselage. The bulge changes the flow direction and flows in the direction away from the inlet. When it approaches the inlet, it is squeezed by the central high-pressure air flow and completely squeezed out of the inlet. In this way, the intake port does not have to leave a certain distance from the fuselage, and the intake efficiency is increased. In addition, the bulge also acts as a pre-compression, similar to the oblique shock generated by the partition, but without the action cylinder mechanism of the partition. The weight and cost of the structure are greatly reduced. However, the total pressure recovery coefficient of this inlet is slightly lower than that of the CARET inlet.

Next I answer the simplest question, which I guess most Indians here don't know, Why is a supersonic inlet different from a subsonic inlet? We all know that the higher the air velocity, the lower the pressure,
Overflow to the engine air speed is too high, then the air pressure will be too low, will lead to engine blade stall, leading to engine failure shutdown
So all the various inlets that we see are designed to compress and decelerate supersonic gas, the pressure increases, which capability determines the efficiency of the inlet

All that's great, but it was judged that speed above mach 1.6 is practically useless unless you can manage higher speeds via supercruise. In the IAF, even the MKI has been operationally restricted to mach 1.8-1.9.

It will be impressive if you can do mach 2 and beyond via supercruise though.

 

[Saaho]

I never said the only solution for dsi itself to mentor a modern fighter, Any fighter that focuses on supersonic flight not uses a fixed inlet, which reduces its efficiency dramatically at supersonic speeds. Of course you can use other inlet, the best inlet is of course the f 15 inlet,Four-wave supersonic inlet with adjustable external pressure，

All designs are compromises meaning you choose one character and you loose others.

Tejas chose a simple low weight pitot intake design with lower chance of mechanical failure and ease of manufacturing. It chose a good quality engine with good SCBs. It also chose airframe life. It also chose tail-less delta wings for great supersonic lift to drag ratio and higher lift at higher angle of attack. This gives is excellent manuverability at supersonic speeds. All these are excellent for high speed combat in WVR regime. BVR regime is more determined by sensors and network than anything else.

Now mach 2.0+ regimes are no longer in favour for reason that I am sure you know. Its not the cold war era anymore, right?

So we have a 1.5-1.6 mach max speed plane with excellent supersonic lift to drag ratio. In actual combat load, the fight will be much close to mach 1.2 than mach 1.5. This is a reality of modern day fighter jets.

So how does a pitot intake perform in 1.0-1.5 mach numbers?

A 1 shock pitot design like tejas will have > 0.9 intake pressure recovery ratio. Thats pretty good for the purpose it serves. Can DSI be better? well if we were aiming for higher machs, certainly. For upto mach 1.5-1.6 pitot is good enough.

 

[screambowl]

Enough of your CCP propaganda. Tejas is far better than your Junk Fighter-17 in every single aspect. In fact, MK1A would prove a worthy foe to even J-10C. Your propaganda posts have no semblance of reality in them. So just stop it before you make a fool out of yourself.

Most probably tasked to gain osnit on what Indians know about plaf.

 

[vstol Jockey]

@lx111, Mig-21 has biconic movable supersonic Intake which is good for speeds above Mach 2.5. In the initial testing of Mig-21 as a prototype, the aicraft had hit even Mach 2.6. So please educate yourself about intake designs. Calling Mig-21 intake a fixed intake shows how little you know about intakes.

 

[Bon Plan]

It's a problem if the Rafale's only advantages become hardware and software maturity while leaving next gen to the Indian industry.

RBE2 XG is already on the drawing board.
So is probably a MLU engine.
So is Spectra
etc....

 

[randomradio]

RBE2 XG is already on the drawing board.
So is probably a MLU engine.
So is Spectra
etc....

All the new tech is for 2035. In India, we could see a GaN radar service entry before 2028 on the MKI. We already know the EW suites on LCA Mk1A and MKI MLU will be GaN. And LCA Mk2 will also have GaN by 2031 or so.

So Indian jets will be half a generation ahead in terms of hardware before 2030. And by the time XG is introduced, we could also be in the next phase of avionics with the final phase of MKI MLU and LCA Mk2 alongside AMCA with similar grade of avionics as XG.

The Indian industry is set to overtake the French industry at a rapid pace. So the only thing the French have right now is a 5-10 year maturity advantage over India.

MRFA as well would see Rafale participating with GaAs while a few competitors like the Typhoon can enter with GaN.

 

[Saaho]

@vstol Jockey . I have a question sir. What is a supercruise fighter? One that never has to use its after burners to achieve supersonic flight? Or one that uses after burners to achieve necessary altitude and velocity and then sustains cruise without afterburner from there on?

 

[Rajput Lion]

As per USAF, supercruise is to reach supersonic speeds of Mach 1.5 or over "without the use of afterburners".

 

[vstol Jockey]

@vstol Jockey . I have a question sir. What is a supercruise fighter? One that never has to use its after burners to achieve supersonic flight? Or one that uses after burners to achieve necessary altitude and velocity and then sustains cruise without afterburner from there on?

supercruise is the ability of an aircraft to go to supersonic speeds from subsonic speed without the use of afterburner and sustain that supersonic speed on dry thrust only. However due to sudden very high increase in drag in transonic speed regime, some aircraft need afterburner thrust to breach the transonic regime and then sustain supersonic speed on dry thrust alone. This too is called supercruise. Once the aicraft settles in supersonic speed, the requirment of thrust reduces because the drag reduces.

 

[screambowl]

However due to sudden very high increase in drag in transonic speed regime, some aircraft need afterburner thrust to breach the transonic regime and then sustain supersonic speed on dry thrust alone.

Can't this drag be reduced by the application of supercritical airfoil so that there is no need of afterburner at all or even then little bit of afterburner is required?