India's LCA Tejas in Trouble ?

[White and Green with M/S]

Did you bring this range out of your arse.

Dude JF 17 too runs on jet fuel not Anti matter, 1300kms my foot

Do you have any butthurt I'd you have apply pain killer on your butts this is not I am saying but many respected military sites are saying like Jane's defense weekly/aviation weekly/flight global etc etc

 

[Faceless]

Do you have any butthurt I'd you have apply pain killer on your butts this is not I am saying but many respected military sites are saying like Jane's defense weekly/aviation weekly/flight global etc etc

These websites don't mean jack sh*t to me if they are devoid of basic common sense.

What these so called military sites wrote are technically true but they almost always lack the much needed context.

For example is Tejas case, these websites say it's combat radius is 500km (which is the combat radius of IOC Tejas without drop danks where as JF 17s 1300km is with drop tanks)

 

[White and Green with M/S]

These websites don't mean jack sh*t to me if they are devoid of basic common sense.

What these so called military sites wrote are technically true but they almost always lack the much needed context.

For example is Tejas case, these websites say it's combat radius is 500km (which is the combat radius of IOC Tejas without drop danks where as JF 17s 1300km is with drop tanks)

Lol you don't believe them OK but these sites knows better than both of us technically

 

[VkdIndian]

And a loser like you would always change his goal posts.

Losers always cry when they loose and always claim that they lost because goal posts were shifted.

Keep trying and working hard. Tera time bhi aayega aur tu bhi jeetega kabhi. Abhi tera time nahi aaya hai.

Explain in simple non-technical lay language. What is combat radius?

Being an administrator doesn’t make one knowledgable. Give him some slack here.
He could have definitely brought in some sanity by not get into trolling but doing his job of administering.

 

[indushek]

How many Tejas are flying with IAF currently? And which engines are they flying with?

A total of 40 LCA Tejas have been built and inducted so far (No 45 squadron and No 18 squadron, both based at Sulur in south India. Recently one of these two squadrons i think was moved to Srinagar)

This is in addition about 10 aircraft, that are used for testing weapons and radar and sensors etc. One of these was modified or perhaps built, as a naval version. IT actually landed on the aircraft carrier, and is currently used as testbed for forthcoming TEDBF.

Another 83 are on order, out of which 10 are trainer/dual seat aircraft, and rest single seat/combat aircraft. The first of the trainer aircraft has been handed over as well

The engine F404 IN20 has some enhanced configuration

F404 | GE Aerospace

F404Engine

www.geaerospace.com

75 engines have already been delivered, and a contract for 99 additional engines signed in 2021. Delivery was supposed to start from this year August, which hasn't happened.

 

[indushek]

Please share a link to that discussion

Claims regarding the Tejas's range and combat radius are often based on a 2013 The Hindu interview of Dr. K Tamilmani, the former Chief Executive of CEMILAC. In the interview, Dr. Tamilmani discussed the specifications of the Tejas Mk1 and claimed Tejas has a speed of 1350 km/h (1.25 Mach), G limit of 7G, combat radius of 400-500km and an angle of attack of less than 24 degrees[vi], However The date of publishing of the article makes it quite clear that he was talking about IOC 1 standard Tejas mk1 which had a limited flight envelope.

But now that the Tejas is FOC certified, its flight envelope has expanded. the FOC standard Tejas has an increased max speed of Mach 1.6, a G limit of 8G (can be pushed to 8.5G), and an angle of attack of 28 degrees so to think that the range of Tejas would not have increased too would be foolish.[vii]

But before going any further let’s define some key terminologies, shall we

Range: The maximum distance an aircraft can travel (from point A to B) solely on internal fuel in most economical conditions.

Ferry Range: The maximum distance an aircraft can travel (from point A to point B) using internal fuel and drop tanks in most economical conditions.

Combat Radius: The distance an aircraft can cover (from Point A to B and back to A) on its internal fuel and represents an aircraft's operational capabilities.

Although no official documents provide the updated combat radius, during the Singapore Airshow, the Tejas flew approximately 3200 km from Sulur Airbase to Changi Airport with three drop tanks and no in-flight refueling indicating a ferry range of around 3200km.

Which is comparable to the Saab Gripen C/D, a fighter in the same weight class with the same engine. So, if we extrapolate this and even consider in a 15-20% range reduction due to inefficient air intakes and aerodynamic drag, Tejas's combat radius can be estimated to be between 650 and 700 km (Gripen has a combat radius of 800km) which by no means is small.[viii]

Above is a little clarification on the combat radius of Tejas, and why this 500 Km radius is peddled around often. It was the radius given for aircraft with IOC only. The aircraft inducted will not have flight envelope limitations, and a conservative estimate puts it at 700 Km.

Note that the ferry range is about similar to Gripen or F-16, so its impossible that the combat radius will be just 500 Km. Problem is IAF doesn't often mention such details, so speculations is what we got.

 

[Azadkashmir]

india should buy off me i got these for lca tejas.

 

[Jammer]

Did they say why?

Without getting into the complicated calculus of geo-politics. The US government knows the following: push a technologically advanced nation like South Korea (and others like Turkey, etc.) into a tight position, and then these nations can easily (perhaps grudgingly; read "comparative advantage" in macroeconomics) pivot to producing their own solution and at that point, you have lost a customer forever. With India the US perhaps realizes that they have time, maybe they feel that India is relatively far away from producing its own solution, in other words, India has no option, it will wait and like it.
Also, please do not confuse space launch and moon landing capabilities with the ability to produce fighter engines. Though comparable, these are two different things. What India did to land on the moon is an extremely impressive achievement but the technology and process (rockets, computations, communication, and software knowledge) are more than half a century old. In the world of jet engines, where most nations are challenged is in the area of metallurgy, which can withstand and recover from repeated changes in heat and pressure instead of the one (usually) time associated with a rocket or booster. This is a dark art that is difficult to master and is a closely guarded secret, that is why there are just a few nations on the planet that can do it.

 

[indushek]

Without getting into the complicated calculus of geo-politics. The US government knows the following: push a technologically advanced nation like South Korea (and others like Turkey, etc.) into a tight position, and then these nations can easily (perhaps grudgingly; read "comparative advantage" in macroeconomics) pivot to producing their own solution and at that point, you have lost a customer forever. With India the US perhaps realizes that they have time, maybe they feel that India is relatively far away from producing its own solution, in other words, India has no option, it will wait and like it.
Also, please do not confuse space launch and moon landing capabilities with the ability to produce fighter engines. Though comparable, these are two different things. What India did to land on the moon is an extremely impressive achievement but the technology and process (rockets, computations, communication, and software knowledge) are more than half a century old. In the world of jet engines, where most nations are challenged is in the area of metallurgy, which can withstand and recover from repeated changes in heat and pressure instead of the one (usually) time associated with a rocket or booster. This is a dark art that is difficult to master and is a closely guarded secret, that is why there are just a few nations on the planet that can do it.

Would have been relevant if there was a prolonged delay

Not if its just two months as on date, and there is no official statement given by any invested entity over here.

Its just media writing articles and speculating, with no information whatsoever on what has been discussed between HAL and GE. Only future can tell, if what you say is true.

 

[Jammer]

Would have been relevant if there was a prolonged delay

Not if its just two months as on date, and there is no official statement given by any invested entity over here.

Its just media writing articles and speculating, with no information whatsoever on what has been discussed between HAL and GE. Only future can tell, if what you say is true.

As they say "Party tu abhi shuru hui hai jani", India has signed a pact with the devil, lets see what happens .

 

[ST1976]

Why are you bashing on US. No engine for you.

we're flooding the west and will take over soon

Pajeets have already taken over the UK, we're also crawling all over both the left and the right in the US.

USA entered India with mainly P8i and transport aircrafts type deals. there are typical Soviet era think tank in India who will get more blood because of this type of news. India will now be more willing to think off building its future on this type of news. the Hindu article as below for Mig35s would now move forward...
its something we all know, if Russia has this Mig35s then it might have a good share in its development by Indian engineers also. Mig35s is more a home projects for India.
the space given to US-Nato in Indian politics will be discouraged by this type of news.
India is no Brazil type country. India, China, Russia are true non western countries. with this type of news, Soviet era trained think tank will get encouragement for building Indian future while taking care of US

IAF’s acquisition of 114 fighter jets to be part of a major procurement plan​

February 16, 2023

The delayed process for the procurement of 114 multi-role fighter jets (MRFA) is set to take off soon and along with three different indigenous fighter development programmes, will result in a mega 500-fighter aircraft acquisition process for the armed forces. This would arrest the dwindling fighter strength of the Indian Air Force and enable it reach the sanctioned strength of 42 squadrons.

https://www.thehindu.com/news/national/iafs-114-fighter-tender-to-move-in-3-4-months-part-of-over-500-jet-procurement/article66516620.ece

.

 

[Bilal9]

Without getting into the complicated calculus of geo-politics. The US government knows the following: push a technologically advanced nation like South Korea (and others like Turkey, etc.) into a tight position, and then these nations can easily (perhaps grudgingly; read "comparative advantage" in macroeconomics) pivot to producing their own solution and at that point, you have lost a customer forever. With India the US perhaps realizes that they have time, maybe they feel that India is relatively far away from producing its own solution, in other words, India has no option, it will wait and like it.
Also, please do not confuse space launch and moon landing capabilities with the ability to produce fighter engines. Though comparable, these are two different things. What India did to land on the moon is an extremely impressive achievement but the technology and process (rockets, computations, communication, and software knowledge) are more than half a century old. In the world of jet engines, where most nations are challenged is in the area of metallurgy, which can withstand and recover from repeated changes in heat and pressure instead of the one (usually) time associated with a rocket or booster. This is a dark art that is difficult to master and is a closely guarded secret, that is why there are just a few nations on the planet that can do it.

Well explained, could not have said it better myself brother.

We are talking not only advanced-alloy metallurgy - we are talking how to keep these metal parts smoothly functioning (with lubrication, needle bearings, oil-metal you name it) given the coefficient of rapid heat expansion and contraction like you said.

And then - cut corners on cost and lengthen MTBO on top of that - whew! Not to mention the mechanics of a variable nozzle geometry, but we're not talking about that here....

These factors are only understood after thousands of hours of bench-testing.

I read someplace that the Russians learned early in the seventies how to forge titanium turbine blades using precision forging in one go, unlike thousands of hours of machining them from monolithic metal slabs. At least they reduced the time to machine for sure...

 

[Faceless]

These figures were discussed in detail last year wherein some learned members from both the sides had given worthy comments.

Both the aircraft have similar size, fuel capacity and load carrying capability. The difference in ferry range and combat range is likely to be very small and insignificant.
But not for the trolls. For them, Jeff shuts it’s engines midair and coasts without any power due to it’s superior aerodynamic design.

Note: I am taking a very simplistic view of aircraft range here for academic purposes. In reality, calculating the range is a complex problem because of the large number of variables involved. An aircraft's flight is not conducted at a single ground speed but varies from zero at take-off, to cruise conditions, and back to zero at landing. Extra fuel is expended in climbing to altitude and in maneuvering the aircraft. The weight is constantly changing as fuel is burned, so the lift, drag, and thrust and fuel consumption rate are also continually changing. On real aircraft, just like with our cars, there is usually a fuel reserve and the pilot makes sure to land the plane with fuel still on board, however we are going to neglect all of these effects for keeping our calculations simple


R (Aircraft Range) = V (cruise speed) × T (Maximum time in air)

[ Generally military aircraft cruise at a height of 30k feet with a speed of 0.8 to 0.85 mach, V would be near 275m/s ]

T = M/(SFC × F)

[ M = Fuel Load (the amount of fuel an aircraft is carrying in Kg), in our case M = 2486kg ]
[ SFC = amount of fuel needed to be burned in 1 sec to produce 1kN of thrust, in our case SFC = 23g/(kN.s) ]
[ F = Thrust needed to keep the aircraft cruising at the given parameters ]

[ Note : At cruise speed an aircrafts Lift (L) = aircrafts Weight (W) and Thrust Required (F) = Drag (D) or in other words L/D ratio (lift to drag ratio) = W/F ]

So now F = W ÷ (L/D ratio)

in other words an aircrafts Range R = {V × M} ÷ {SFC × F}

So our Tejas will have a range of {275 × 2486} ÷ {23 × F}

Given that we don't know the required F for keeping the Tejas crusing we would have to look for another aircraft of similar profile and extract the data from there using the above equations.
Gripen C/D seems to be the closest fighter to Tejas with similar empty weight (6800kg), fuel capacity (2340 kg) and same GE 404 engine, so now using the Gripen's data we can calculate the required F

F = {275 × 2340} ÷ {23 × 1500km (Conservative Range)}
F = 18.65 kN

Assuming that Tejas will need similar (or even greater) thrust of let's say 20kN for crusing due to it's aerodynamic design we can now calculate the range of Tejas

Range of Tejas = {275 × 2486} ÷ {23 × 20} = 1486km.

This range however is highly conservative as we don't know the actual L/D ratio or the thrust required for crusing and thus have taken the most conservative values of all the variables, (Eg. Range of Gripen C/D, Fuel Capacity of Tejas etc).

* Both Tejas and Gripen's Range is calculated in clean configuration

sources https://www.grc.nasa.gov/www/k-12/BGP/sumran.html

Saab JAS 39 Gripen - Wikipedia

en.wikipedia.org

General Electric F404 - Wikipedia

en.wikipedia.org

HAL Tejas - Wikipedia

en.wikipedia.org

 

[VkdIndian]

Without getting into the complicated calculus of geo-politics. The US government knows the following: push a technologically advanced nation like South Korea (and others like Turkey, etc.) into a tight position, and then these nations can easily (perhaps grudgingly; read "comparative advantage" in macroeconomics) pivot to producing their own solution and at that point, you have lost a customer forever. With India the US perhaps realizes that they have time, maybe they feel that India is relatively far away from producing its own solution, in other words, India has no option, it will wait and like it.
Also, please do not confuse space launch and moon landing capabilities with the ability to produce fighter engines. Though comparable, these are two different things. What India did to land on the moon is an extremely impressive achievement but the technology and process (rockets, computations, communication, and software knowledge) are more than half a century old. In the world of jet engines, where most nations are challenged is in the area of metallurgy, which can withstand and recover from repeated changes in heat and pressure instead of the one (usually) time associated with a rocket or booster. This is a dark art that is difficult to master and is a closely guarded secret, that is why there are just a few nations on the planet that can do it.

Valid argument to describe the art and science of jet engines.

India is still a little far away from mastering it. If given a shove, it can’t produce 404 class engine for some time to come and any significant delay by GE can cripple Indian domestic fighter programs.

However, India knows the nature of Geo-politics and has’t put all the eggs in one basket. India has been in serious negotiations with French and the British for developing new engines for its future fighter programs. A deal with US has been already signed for GE414. Hence, this is not the end of the road for India.

For GE404, there can’t be an immediate replacement as changing to a new engine midway isn’t an easy solution but a complete redo.

It is also a little speculative that US has completely refused just because there is a news of a delay. Most likely a jumpy Indian media has to analyse each and every issue as if, it is a doomsday, while there may not be anything significant.

You are also right in saying - Abhi party shuru nahi hui hai. But, it is not a time to say cheers yet. Some people on pdf have always started a party a little too early in the hope of mega win and have fallen flat on their faces. Not you, but many others have displayed poor judgement in this regard.

This range however is highly conservative as we don't know the actual L/D ratio or the thrust required for crusing and thus have taken the most conservative values of all the variables, (Eg. Range of Gripen C/D, Fuel Capacity of Tejas etc).

Great effort.

Now @Windjammer, would vanish from this thread. Because you have put more maths and logic in one post than he would have seen in his entire lifetime.

I might be wrong though, because stupid people have strange ways and logic to keep arguing.

 

[indushek]

As they say "Party tu abhi shuru hui hai jani", India has signed a pact with the devil, lets see what happens .

Haha I won't disagree

A country with lesser standing geopolitically/economically and militarily, dealing with another country who is stronger in all these factors, will always seem like deal with the devil. This will hold good for any pairing with this imbalance, and not just for USA.

I however have confidence in our Govt, to at least not sign away ourself to a level where we have no say in matters. No one can predict future exactly, so let's wait and see how the party shapes up.