IIRC I asked you to stop posting until you get me a source saying LCA's initial payload was 2 tons as you earlier claimed.
I have been correctly referring to the initial weapon load as 4 tons as per original ASR as stated by air marshal WOOLEN at least 5 times in this forum. But you are asking for a source for the supposed 2 ton claim ,which I said once very early in my debate with you, when comparing tejas as a mig-21 replacement without checking.After googling I have posted the correct figure and no need for your raking up source issue here.Just discuss the issues that are relevant here.
But what about the other details in his article like
1.top speed of mach 1.5 at tropopause,
2.8G,
3.MTOW of 12 tons,
4.17 deg turn rate,
which were all revised further ,
as usual you wont talk about it.
Ever heard about air density? How much air do you think is available at flight ceiling of LCA for it to cross such high mach speeds without variable inlets?
I know bloody damn well what air density is/ That's the reason why fighters that scream past mach 2 in service ceiling are limited to mach 1.2 at sea level.So there is no need for you to teach anything about it.
Damn based on the same principle I am repeating here that tejas with airframe capability of
mach 1plus at sea leve
and
mach 1.6 at 7 km altitude
can go past mk-1.8 in service ceiling w
with redesigned air intake.
All the time you are arguing against it and now you are asking what is air density?
You have two major choices to get past high mach speeds. One is the inlet design, which needs to be variable so it is able to reduce the effect of shock waves that decrease air pressure before entering the fan. In a fixed inlet design like the LCA, there is a only one particular maximum mach number where the inlet is able to prevent air spillage and that's somewhere between Mach 1.4 and Mach 1.5 currently. So, this is the best LCA can do once a certain altitude is reached. After that it remains constant and actually reduces in LCA's case because LCA's inlets are too small and the LCA is too heavy. There is decrease in power. Aux intakes have helped a bit, but only a bit. With variable inlets the inlets angle can be made bigger or smaller based on flight profile in order to absorb shocks and hence adjust the mach speed accordingly because more air can be pushed into the inlets.
Altitude plays a very important part. The best speeds for LCA type aircraft are at medium altitudes. As an example, power reduces by 500Kg simply because the aircraft is flying over Bangalore which is around 600-800m above sea level. It's not like LCA is pumping out huge amounts of power. It is quite modest if you compare F-16A came with a 11 tonne engine while it weighed 6.5 tonnes.
WHAT KIND OF INTAKE GIVES A TOPSPEED OF MACH 2 to MIG-21?
a) diverter less supersonic intake
b)same type as LCA TEJAS
c)variable air intake
d)none of the above
please click the correct answer for the above question.
You will see a similar drop in air speed if you compare Su-35 and Su-34. Su-35 comes with variable inlets which allow the aircraft to go beyond Mach 2.2 whereas the fixed inlet design restricts the Su-34s speed to Mach 1.6.
We can either use intake ramps like on F-15 or cones on Mirage-2000 and Mig-21. But, LCA isn't designed with any speed above Mach 1.6.
ADA explicitly says that tejas has been designed for a top speed of mach 1.8 at service ceiling in mk-I and mach 2 plus for MK-2.It is silly stuff to say otherwise.And it says it has achieved mach 1.6 within the 85 percent opened flight envelope.Any kind of measures can be used to optimize the air intake for these speeds provided the engine gives enough thrust..
The second option to increase speed even with fixed inlet is with new generation engines that are able to burn nearly* all the air that enters the combustion chambers. The so called 5th gen engines like the F-119, F-135 and Type 30. This is merely a combination of very high efficiency engines combined with very high power output along with increased T/W ratio. That's the reason why the F-22 is so unique that it is able to achieve speeds far greater than Mach 2 regardless of its fixed inlet design. Even F-16 can achieve slightly higher speeds up to mach 2 because of greater power along with a good inlet design.
What kind of new generation engines that are able to burn nearly* all the air that enters the combustion chambers are used in MIG-21 achieve mach 2.05 top speed?
So, there is a chance we may see greater mach speeds with a 100-120KN engine on LCA (if there are no major weight gains on the aircraft), but that again depends on the inlet design which can handle accepting a greater volume of air. As a small fighter there is a limit to space on the aircraft and hence is not a primary requirement for any modern air force. It is better to use the lighter and cheaper fixed inlet and have greater volume for fuel and electronics. Fixed inlet also allows greater ability to shape it, like S shape on F-22 for stealth characteristics. Today's air force is less about top speed and more about endurance + electronics.
What kind of space limits are there on the outside of small fighters where a major portion of air intake is situated?
Then how ADA says it an intake size just 5 percent higher than the one in mk-1 will be sufficient to reach mach 2 plus speeds in MK-2?
So are you saying there is no space indie and outside tejas for this less than 5 percent enhancement in air intake? that will be enough for mk-1.
You are still hung up on that small difference of 0.2 mach as though it is supposed to prove something for the LCA.
Max STR for LCA is still 17 deg/s. G requirement was always 8 - 9.
This 8-9 is a patently wrong way of defining ASR which you are using very liberally in this forum.Please specify whether it is 8 or 9?
Structural limit was always 12G. And what's that nonsense about 40Km BVR? BVR wasn't even a requirement for LCA. We received our first BVR missiles only with Mig-29s, well after the ASR was made.BVR requirements on LCA came much later and IAF chose Derby for it. This happened post 2000. LCA's short range requirement was based on R-60 and that changed to R-73 before first flight happened.
p2prada ↑
That's what I am exactly saying much later. There is an article by former SA to PM PARTHASARATHY on this.Are you saying his article is wrong?He explicitly says that due to the change in requirement by the user IAF wings were further strengthened to carry longer range more heavier BVThis was the reason for higher weight of tejas.The GTRE chief Mohan RAO also said the same ,go to KAVERI ENGINE thread and read his press statement.How can you gloss over such a factual statement as nonsense?
The following article by Mr. Parthasarathy, former scientific advisor to the Prime Minister, and Vice Admiral (retd) Raman Puri not only describe the case for the continuation, but also the enhancement of the Tejas and most importantly, its case as an MRCA contender.
The authors were the apex authorities on defence procurement of the 3 services upto 2006. This article is very important in that regard :
The case to support the indigenous LCA programme
Ashok Parthasarathi and Raman Puri
The facts with regard to perceived cost and time overruns and performance shortfalls in perspective
There have been several articles in the press critical of projects of the Defence Research and Development Organisation (DRDO) in general, and specifically the programme relating to the Light Combat Aircraft (LCA), now named Tejas, and the Integrated Guided Missile Development Programme. Indeed, whenever a significant event that involves indigenous R&D, particularly defence-related, occurs, or a crucial decision is set to be taken, articles originating from within the defence "system," or from vendors who see their business prospects threatened, appear. The real facts relating to the programme need to be put in context.
The two issues on which the LCA project is criticised are cost and time overruns, and performance shortfalls. As regards the so-called time overruns, when the zero/go date for the project is taken as 1983, the critics fail to mention that what was sanctioned in 1983 was an ad hoc 560 crore, pending full preparation of the Project Definition Document (PDD) — which is a fundamental step even to start the design and development process. The costs were to be finalised based on the PDD. This required the setting up of infrastructure in a hundred academic institutions and R&D laboratories and building up expertise to undertake the fundamental and application-oriented R&D required, and harnessing the design and engineering effort available largely in the public sector units for such a complex, state-of-the-art aircraft. The Aeronautical Development Agency (ADA) discussed with Air Headquarters the Air Staff Requirement (ASR). Air Headquarters had requirements added to what was originally to be a replacement for the MiG-21. As a result, the ASR that was finalised was practically that for a Mirage 2000. But in the public perception the LCA remained as a replacement for MiG 21.
It look seven years, till 1990, to formulate the PDD. Based on this the ADA, in a report to the Ministry of Defence in 1990, gave a time-frame of seven years to develop the LCA and projected a financial requirement of 4,000 crore. This included the building of four prototypes also. There had been a 25-year gap since the only fighter aircraft ever indigenously designed, developed and manufactured, namely the HF-24 Marut, had entered squadron service. So the period of seven years to set up a more advanced R&D infrastructure and build up even the core personnel needed to develop the technologies that the LCA's ASR and PDD called for, was modest.
After consideration, including by special committees, the Indian Air Force and the government gave the real operational go-ahead only in late-1993. Even that "go-ahead" covered the development of only two Technology Demonstrator Aircraft (TDA) without weaponisation. The funding approved was only of 2,000 crore — half the amount requested for full-scale development. The first TDA flew in 2001, eight years from the real operational 'go' date, despite much additional R&D work that had to be undertaken due to the U.S. sanctions imposed in 1998.
Comments appeared in the media in 2001 quoting IAF sources to the effect that what the ADA had achieved was just a flying machine that was yet to be weaponised. Considering the nature and scope of the approval accorded in 1993, what else was to be expected? Using the money sanctioned for two TDAs, the ADA built four. Full-scale development, for which another 2,000-plus crore was finally sanctioned, thus started only in late-2001. Some 1,200 hours of flight testing was to be undertaken to secure Initial Operational Clearance (IOC) from the IAF.
At that point, apart from the weaponisation requirements the project had to undergo extensive redesign to accommodate an air-to-air missile chosen by the IAF, which was considerably heavier and longer than what had been specified till 2000. The IAF had again changed its mind. This necessitated the complete redesign of the wing structure, using only composite materials in order to keep the weight within limits. The period of this redesign was also utilised to upgrade the avionics, to a completely open architecture.
Consequently, in "generational terms" the LCA is a fourth generation-plus aircraft with full networking capabilities. This made it more than comparable to anything the IAF had, and possibly would have, even after it acquires the 126 Multi-Role Combat Aircraft (MRCA) now on tender, with first deliveries due eight years hence.
On the engine
Further discussions on these issues must be shifted to TEJAS IV thread here as it is no longer relevant to discuss the issue in GE finally gets the engine order for mk-2 in the following link
http://defenceforumindia.com/forum/...nally-gets-lca-engine-order-4.html#post645950
as these issues are not relevant to a discussion there and members may miss a chance to contribute to issues regarding tejas and correct any mistakes if there is one.
