ADA Tejas (LCA) News and Discussions

[patriots]

https://www.quora.com/Is-the-Indian.../answer/Sree-Raj-127?share=42e5b795&srid=cGlT

Debunking Some False Arguments about the LCA Tejas

 

[ersakthivel]

Radome has been indigenised. The ToT for silica radome has been given to private company already. Weapons like Astra, LGB are developed, design is decent enough but outdated as initial specification was different. UTTAM is almost ready and will most likely be fitted to MK2 or even Mk1A. Kaveri also has been tested already. What is the problem you have exactly?


Do you understand the meaning of flat rating? Flat rated thrust is not full peak thrust. Also, the peak of 81kN, bypass of 0.16 etc are impractical and contradictory to the specification which states that Kaveri is a flat rated variabe cycle engine. Variable cycle means that bypass can change as per requirement and flat rated means that the peak thrust is controlled to a flat rated thrust to ensure stable peak thrust with altitude.

I flat rated engine estimates turbine is designed with a lower TET Temp for sea level.

& designed to achieve its design peak TET & and thrust at operating altitude.

So there is more that that meets the eye on kaveri's 80 KN achieved thrust potential


Since engines that can reach 80KN at high altitude can theoretically achieve more thrust at sea level.

But to unlock that it has to be finished, certified at the current trust level first.

 

[Kshithij]

The engines are not made in 2 stages. EJ200 was not initially made for 80kN and certified before going to 90kN. India already has made engines in the past like R25B of MiG21 Bison, RD33 (except blades) for MiG29 and complete Al31F for Su30. So, India is not just starting to make engines.

Also, I find the flat rating concept as wrong. In sea level, for quick take off, one needs higher thrust whereas in upper altitudes, lower thrust is enough to maintain speed as the air drag is less. This is the reason why no country has made flat rated engines. The decrease in thrust of engines is equal to decrease in air drag over altitude and hence it makes no sense to have flat rating.

One can get the correct specifications of Kaveri only after it is publicly displayed. The recent news that it has been certified for limited envelopes may mean that the full and correct specifications of Kaveri will be released soon. For now, the numbers of 81kN peak thrust and 0.16 bypass ratio is to be considered with a grain of salt

I flat rated engine estimates turbine is designed with a lower TET Temp for sea level.

& designed to achieve its design peak TET & and thrust at operating altitude.

So there is more that that meets the eye on kaveri's 80 KN achieved thrust potential


Since engines that can reach 80KN at high altitude can theoretically achieve more thrust at sea level.

But to unlock that it has to be finished, certified at the current trust level first.

 

[Karthi]

Flat rated engines allows aircrafts to work in various conditions , we know india has a diverse climate and geography across the country , we need to fight in extreme cold in J&K and Himalayas , intense heat, high humidity in South India , so a flat rated engine can guaranty a constant performance across the country. Also a flat rated engine has better engine cooling characteristics .

{
The rating of a jet engine is the thrust performance that is guaranteed by the manufacturer for a new engine under specific operating conditions such as, take off, maximum continuous, climb, cruise.

Some non Prat and Whitney (P&W) engines are rated to a constant compressor speed (RPM). P&W rates there engines to a constant exhaust gas temperature (EGT). This is referred to as the flat rating concept. To get your head around this concept you must understand the following principle.

The temperature and density of the ambient air vary inversely.
Lower temperature = > Higher Density
Higher Temperature = >Lower Density

The amount of airflow (lbs/sec) through the engine is a function of compressor speed and air density. It is greater when the compressor speed and density are high.

The compressor speed is a function of the energy available to the compressors turbine. That energy comes from the combustion or air and fuel, so the turbine turns faster when the fuel flow rate is greater. The compressor speed is also a function of the airflow through the compressor. Higher rates of air flow reduce the speed of the compressor.

The compressors rotational speed and the amount of airflow through the compressor are independent, they affect each other though.

The turbine inlet temperature is proportional to the energy available to turn the turbine. The exhaust temperature is proportional to the turbine inlet temperature. So a higher EGT corresponds to a larger amount of energy to the turbine so it can turn the compressor faster.

When EGT is held constant, or lowered the result is a prolonged hot section life and at the same time provides the thrust to meet the certification requirements.

}

 

[Kshithij]

Flat rated engines allows aircrafts to work in various conditions , we know india has a diverse climate and geography across the country , we need to fight in extreme cold in J&K and Himalayas , intense heat, high humidity in South India , so a flat rated engine can guaranty a constant performance across the country. Also a flat rated engine has better engine cooling characteristics .

{
The rating of a jet engine is the thrust performance that is guaranteed by the manufacturer for a new engine under specific operating conditions such as, take off, maximum continuous, climb, cruise.

Some non Prat and Whitney (P&W) engines are rated to a constant compressor speed (RPM). P&W rates there engines to a constant exhaust gas temperature (EGT). This is referred to as the flat rating concept. To get your head around this concept you must understand the following principle.

The temperature and density of the ambient air vary inversely.
Lower temperature = > Higher Density
Higher Temperature = >Lower Density

The amount of airflow (lbs/sec) through the engine is a function of compressor speed and air density. It is greater when the compressor speed and density are high.

The compressor speed is a function of the energy available to the compressors turbine. That energy comes from the combustion or air and fuel, so the turbine turns faster when the fuel flow rate is greater. The compressor speed is also a function of the airflow through the compressor. Higher rates of air flow reduce the speed of the compressor.

The compressors rotational speed and the amount of airflow through the compressor are independent, they affect each other though.

The turbine inlet temperature is proportional to the energy available to turn the turbine. The exhaust temperature is proportional to the turbine inlet temperature. So a higher EGT corresponds to a larger amount of energy to the turbine so it can turn the compressor faster.

When EGT is held constant, or lowered the result is a prolonged hot section life and at the same time provides the thrust to meet the certification requirements.

}

I know the flat rating concept. The only problem here is the deliberate reduction of thrust which can seriously affect take-off performance and maneuverability. It is best to simply allow the engine to perform to the maximum possible extent rather than controlling or reducing the thrust unnecessarily. There is no advantage of having a stable thrust of 81kN in sea level as well as at 15000feet since the same thrust works differently at different altitudes.

 

[HariPrasad-1]

If we don't have the US engines LCA is indeed in trouble, the only ready alternative would be Russian once and neither Kaveri, nor RD93 offer enough thrust for AMCA. Which then brings back the EJ200 as an option.

https://defenceforumindia.com/forum/threads/eurofighter-ef-2000-typhoon.76395/page-18#post-1442167

EJ 230 is really a top class engine with 72 KN dry thrust and 108 kg wet. It weighs less only 1 ton and has TWC as well.

 

[Kshithij]

EJ230 is a myth. So, it can't be used. Let it first be completed Having such a high TWR is really difficult thing to do and is unlikely to succeed without increase in weight

EJ 230 is really a top class engine with 72 KN dry thrust and 108 kg wet. It weighs less only 1 ton and has TWC as well.

 

[darshan978]

81kN was the development goal for wet thrust, which wasn't achieved and why DRDO asked for Snecmas help for years. But even Snecma only prejected 90kN thrust so far, which IAF considered as not enough either and prefered EJ 200 or GE414 instead and the latter won the competition.
Kaveri/Snecma engine might be able to replace GE 404, in all MK1s someday, but is not enough for a heavier MK2, let alone an AMCA with around 110kN requirements.

In your dream 90kn will not be enough for tejas its your wet dream that tejas will be rejected stop your biased views according to you 78kn gripen c is world class but tejas with 84kn engine is underpowered lol
And ge414 for mk2 is also underpowred but gripen e with same thrust but more(over weight) weight is best ....huh?
Stop hypocrisy...

 

[charlie]

OT but...
...Meteor, Spectra, Arexis, WVR missiles, AASM, Brimstone..., should be obvious examples of superior technology. What Europe lacks is money for projects and common goals, but certainly not know how.

It’s based on requirements, there is more TOT going to Europe rather then other way around.

US gets the best brains in the world, They are better prepared when it’s comes to Human Resources. Don’t even start comparing two, as I said it’s as absurd as comparing Tejas to F35.

Well the know how comes with spending money and time for the project, Chinese will eventually figure out how to mass produce jet engines. Didn’t understand what you are getting at ?

 

[Kshithij]

It’s based on requirements, there is more TOT going to Europe rather then other way around.

US gets the best brains in the world, They are better prepared when it’s comes to Human Resources. Don’t even start comparing two, as I said it’s as absurd as comparing Tejas to F35.

Well the know how comes with spending money and time for the project, Chinese will eventually figure out how to mass produce jet engines. Didn’t understand what you are getting at ?

CHinese already produce their own jet engine. It is only a myth that CHinese don't know mass production of jet engine. Chinese jet engine project started after 2004 and has been completed already.

 

[Enquirer]

All of Chinese aircraft & jet engine technology is STOLEN from US (in fact they've stolen tech ranging from ship building to paint manufacturing to search engine source codes!!!)

I am not even talking about 'reverse engineering'. This is straight forward theft by planting Chinese spies in different US companies & in the recent decades by hacking.

 

[charlie]

it depend.
Meteor is away the best AMRAAM.
ASTER 15/30 has better anti missile capacity than equivalent US product.
Leopard 2 and Leclerc MBT are (slightly) better than Abrams.
HK416 is unrivaled in USA.
...

The main problem of europe is the multiplication of the same kind of weapon : 5 AA frigates, 3 fighters, 4 MBT ... The R&D budget is fragmented.
Once this will be resolved, there is absolutely no reason not to be on par on everything.

.

Well you can say the same about US too there is always competition between design, the F22 vs YF 23 and Boeing design vs Lockheed Martin F35 design to the smallest system.

The one thing Europe isn’t efficient at is attracting best man power in the world, A letter for US Dod does wonders for immigrants.

One thing I notice working for a defence contractor is the number of people going to support the systems in Europe.

I am not trying to belittle European R&D by any means but the way DARPA is going there is just no competition.

 

[tharun]

This thing looks like lca to me

Sent from my Redmi 4 using Tapatalk

 

[Enquirer]

This thing looks like lca to meView attachment 26593

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Dude! That's Mirage-2000 trainer in French Air Force (see the colors!!!)

 

[ersakthivel]

http://www.opindia.com/2018/07/setb...al-allegations/amp/?__twitter_impression=true



If India specific alterations to just 36 IAF Rafales, (which make them more deadly than French airforce raffles) costs 1.7 billion Euros,

i. e close to 40 million dollars per plane,

Why HAL is hauled over the coals for, much deeper upgrades on Tejas MK1A, which cost 20 million dollar per plane.(rest 10 or 15 million will go towards recouping assembly line costs, & other costs is my guess)

The reason for high cost of upgrades I both Rafales & Tejas MK1A is the low order number.

When IAF orders 200 Tejas mk2, it can save money,

because most of the upgrades meant for Tejas mk2(other than engineers e & few more subsystems) are now done in mk1A itself.

In the same way if a couple more squadrons of Rafales are added, IAF or Navy can get savings, because this 1.7 billion Euros cost will now be divided by 72 Rafales.

That's my understanding.

Ordering more Tejas MK1A is another surefire cost saving recipe for IAF & Seeding a viable mil aviation industry.

 

[tharun]

Dude! That's Mirage-2000 trainer in French Air Force (see the colors!!!)

I know it's french plane, I'm talking about design

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[Enquirer]

I know it's french plane, I'm talking about design

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Sure, LCA is based on Mirage-2000, because IAF has always been in love with it. So much so that to keep the old aircraft flying, IAF is spending ~$50 million per Mirage-2000 in the name of upgrade!

 

[lcafanboy]

Dude! That's Mirage-2000 trainer in French Air Force (see the colors!!!)

Guess what 2 French Mirage 2000 are also being given to iaf along with 32 Jaguars... JAI HO. PAPPU will get an egg on his face now...

 

[Kshithij]

The Mirage 2000 will be only 2 in number and jaguars will be 32. But the catch here is that the jaguars are not upgraded to DARIN upgrades as in India but are 2nd hand planes meant as scrap or to cannibalise spares.

The total cost of these is expected to be about 300 million Euros which would still mean that 7.5 billion Euros was spent on Rafale deal excluding these aircrafts.

Guess what 2 French Mirage 2000 are also being given to iaf along with 32 Jaguars... JAI HO. PAPPU will get an egg on his face now...

 

[WolfPack86]

So MMRCA 2.0 is a just smoke screen in disguise to order more Rafales later.