Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby JTull » 15 Nov 2018 14:56

ArjunPandit wrote:Is there any plan for it to upscale Uttam for su 30... I'm salivating on the details


Apologies for going OT.

Chinese now have a 3-aerial AESA offering better coverage.
Image
Su-30MKI have a large radome and considerable power. Perhaps next iteration of UTTAM will incorporate something like this.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 15 Nov 2018 16:05

SaiK wrote:
nam wrote:
Now TFTA Israeli 2052 has 1100+ TRM. The longest row having 34 TRM. If 2052 works for LCA, I would expect IAF asking for 1000+ Uttam.

But, it would (likely) be staged - TFTA 2052 -> Uttam GaAs -> SDRE Uttam AlGaN. We have to go or going for more powerful engine. We need 10 times more power for future Uttams.


The thing is IAF will not like to downgrade from what it will already have. Once 2052 goes in, it will be only be mid-life upgrade LCA and may be MK2 versions. However LRDE needs to keep working on it and bring out better versions, may be like GaN version.

SU30 might be a better candidate, given it is going in for mid life upgrade and there are no option other than Russian for the size of radar that will be required.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 15 Nov 2018 16:10

JTull wrote:
Apologies for going OT.

Chinese now have a 3-aerial AESA offering better coverage.

Su-30MKI have a large radome and considerable power. Perhaps next iteration of UTTAM will incorporate something like this.


It doesn't require to be iteration of Uttam. We have GaS AESA TRM which can be placed using distributed aperture on SU30 to provide large scanning angles, if IAF wants to. The TRM will not have the power of a regular radar and probably is not required.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby brar_w » 15 Nov 2018 17:44

nam wrote:It doesn't require to be iteration of Uttam. We have GaS AESA TRM which can be placed using distributed aperture on SU30 to provide large scanning angles, if IAF wants to. The TRM will not have the power of a regular radar and probably is not required.


I don't think it is as straightforward like you put it. There is a reason why this hasn't been done anywhere in the world. To increase the FOV of RF sensors you can either rotate the AESAs (Gripen E), or have side arrays and utilize the same radar processors (The ATF/PAKFA/Chinese solution). Having distributed RF arrays is a much tougher solution to adopt particularly on the processor side when you are trying to process or fire control with fusion. Not to say it isn't doable but the reason why it hasn't be adopted is precisely because it is going to be processor heavy especially with some of the solutions that look the most attractive ( conformal antennas).

A compromise can be seen on the F-35, where instead of side arrays they put Ku Band AESA T/R antennas and the ICPs handle four ship fusion cooperatively by exchanging raw data (instead of just SA and overlay) from dispersed fighters. This too wasn't an easy nut to crack but on the whole a lot cheaper than provisioning space weight and power for larger RF antennas and then trying to stay within the LPI constraints.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 15 Nov 2018 19:27

brar_w wrote:I don't think it is as straightforward like you put it. There is a reason why this hasn't been done anywhere in the world. To increase the FOV of RF sensors you can either rotate the AESAs (Gripen E), or have side arrays and utilize the same radar processors (The ATF/PAKFA/Chinese solution). Having distributed RF arrays is a much tougher solution to adopt particularly on the processor side when you are trying to process or fire control with fusion. Not to say it isn't doable but the reason why it hasn't be adopted is precisely because it is going to be processor heavy especially with some of the solutions that look the most attractive ( conformal antennas).

A compromise can be seen on the F-35, where instead of side arrays they put Ku Band AESA T/R antennas and the ICPs handle four ship fusion cooperatively by exchanging raw data (instead of just SA and overlay) from dispersed fighters. This too wasn't an easy nut to crack but on the whole a lot cheaper than provisioning space weight and power for larger RF antennas and then trying to stay within the LPI constraints.


No disagreement here, my comments were related to being dependent on growth of Uttam radar to implement such a feature.Just saying that a solution could be independently researched.It would of course be dependent on the requirement from IAF. Will also be dependent on if IAF would want all jets to be able to have large field of view. My thoughts were something similar to what is found in AESA AWACS, where there are 3-4 anntenas and data is fused. It is probably closer to con-formal antenna, that you have mentioned.

May be something similar to ECM/recon pod could used, with the required processing requirement in built, linked to the avionics to provide required data. They could be attached when required on some of the jets. The search image could be share between a group. There are drawbacks in terms of loosing hardpoints, however it would be quite flexible.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby JTull » 15 Nov 2018 20:23

Compared to conformal arrays on the chin I like the 3-aerial approach integrated into the primary radar.
- Duplicating processor, power management and cooling hardware is an avoidable penalty.
- Simpler to retrofit existing aircraft without significant structural changes
- Easier to test the fused picture on static or flying testbeds (because of above point)
- Distributed structure introduces additional LRUs that has it's own maintenance overheads

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby JayS » 16 Nov 2018 20:45

Folks please take the radar specific discussion to Radar thread.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Rakesh » 18 Nov 2018 10:52

nits wrote:We can use Google drive for it with limited shared permission or Google docs also

SBajwa wrote:Google docs

I have completed the spreadsheet in Google docs. Just awaiting a response from BR Webmaster on how to proceed.

Will keep you guys updated.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Gyan » 22 Nov 2018 09:18

Order for Radars and Engines for LCAMK1A must be placed by March 2019 otherwise a gap will appear in the production schedule when the assembly lines would be idle.
It takes around four years for a fighter aircraft to roll out after long lead items are ordered. If I remember correctly the tender for radar and jammers of LCA mark 1 required first delivery of sample pieces after 2 years of the contract and mass delivery after 3 years, therefore fitst LCA MK1A will roll out after 3 years and mass roll out of LCA mark 1a will begin after 4 years of the order being placed.
Setting up of the second production line for augmenting the assembly to 16 aircraft per annum has not started. Therefore the second production line also has to be funded and completed as soon as possible preferably within next 3 years.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Indranil » 28 Nov 2018 02:36

Mk1 is now cleared for 100 knots and 8.5Gs

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Kartik » 28 Nov 2018 02:50

Indranil wrote:Mk1 is now cleared for 100 knots and 8.5Gs


Great news! Hope to see official confirmation of this, at AI-2019. Will they update the FCS software to allow regular line pilots to reach 8.5Gs for the FOC standard software build?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby ramana » 28 Nov 2018 02:51

Kartik, Whats significance of 100 knots? Isn't it too low a an airspeed?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 28 Nov 2018 03:00

Any updates on Uttam testing on the LSP on which it was integrated?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Indranil » 28 Nov 2018 03:13

Kartik wrote:
Indranil wrote:Mk1 is now cleared for 100 knots and 8.5Gs


Great news! Hope to see official confirmation of this, at AI-2019. Will they update the FCS software to allow regular line pilots to reach 8.5Gs for the FOC standard software build?

FCS will be updated for line pilots. I wish that the brochure is updated. That brochure is older than the IOC-1 capable aircraft.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby PratikDas » 28 Nov 2018 03:36

ramana wrote:Kartik, Whats significance of 100 knots? Isn't it too low a an airspeed?

Apologies in advance for speculating but I'd think a low 100 knot airpseed would allow:
  • greater stall avoidance when dogfighting
  • more time for air-to-ground targeting

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Lalmohan » 28 Nov 2018 15:28

100kts would be too low for even take-off, what is it in specific reference to?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Aditya_V » 28 Nov 2018 17:36

I guess in a turning dogfight where airplane is bleeding energy this might be useful

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Lalmohan » 28 Nov 2018 18:25

as in I am sure that 100kts is well below stalling speed in any flight regime for this type of airframe configuration... there must be some other explanation for what it applies to

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby ashishvikas » 28 Nov 2018 18:37

Sp12 made its first flight today.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Rakesh » 28 Nov 2018 18:52

Yes!!!

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 28 Nov 2018 18:58

I don't know what 100kts will be used for, however it tells me the great intake design and FCS we have. The engine is not starved of air and FCS is able to keep the jet in air.

I can do a wild guess, one of the things this will help in reduced landing speed? Helping in a way to NLCA?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby SaiK » 28 Nov 2018 20:24

recovery after stall threshold?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby ramana » 28 Nov 2018 20:39

Can some aero guru tell us what is this 100 knots speed buy for the Tejas?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Lalmohan » 28 Nov 2018 20:40

indranil - what is your source for the 100kts?

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby ramana » 28 Nov 2018 20:54

Chaiwala. What will you do with the source?
Write a paper?
IDRW will do that anyway!

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Rakesh » 28 Nov 2018 21:19

:lol: (laughing at the IDRW bit!!!)

Lalmohan Saar, just take the tidbits that IR gives and do a lungi dance. IR is not one to embellish.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby suryag » 28 Nov 2018 21:36

SP12 completes first flight

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby SaiK » 28 Nov 2018 21:37

may be:

Load Factor. Load factor is the ratio of the lifting force produced by the wings to the
actual weight of the airplane and its contents. Load factors are usually expressed in terms of “G.”
The aircraft’s stall speed increases in proportion to the square root of the load factor. For
example, an airplane that has a normal unaccelerated stall speed of 45 knots can be stalled at
90 knots when subjected to a load factor of 4 G’s. The possibility of inadvertently stalling the
airplane by increasing the load factor (i.e., by putting the airplane in a steep turn or spiral) is
much greater than in normal cruise flight. When an airplane stalls at a higher indicated air speed
due to excessive maneuvering loads, it is called an accelerated maneuver stall. A stall entered
from straight and level flight or from an unaccelerated straight climb will not produce additional
load factors. In a constant rate turn, increased load factors will cause an airplane's stall speed to
increase as the angle of bank increases. Excessively steep banks should be avoided because the
airplane will stall at a much higher speed. If the aircraft exceeds maneuvering speed, structural
damage to the aircraft may result before it stalls. If the nose falls during a steep turn, the pilot
might attempt to raise it to the level flight attitude without shallowing the bank. This situation
tightens the turn and can lead to a diving spiral. A feeling of weightlessness will result if a stall
recovery is performed by abruptly pushing the elevator control forward, which will reduce the up
load on the wings. Recoveries from stalls and spins involve a tradeoff between loss of altitude
(and an increase in airspeed) and an increase in load factor in the pullup. However, recovery
from the dive following spin recovery generally causes higher airspeeds and consequently higher
load factors than stall recoveries due to the much lower position of the nose. Significant load
factor increases are sometimes induced during pullup after recovery from a stall or spin. It should
be noted that structural damage can result from the high load factors that could be imposed on
the aircraft by intentional stalls practiced above the airplane’s design maneuvering speed. Large,
aggressive control reversals can also lead to loads that can exceed the structural design limits,
even at speeds below the airplane’s design maneuvering speed.
h. Center of Gravity (CG). The CG location has a direct effect on

https://www.faa.gov/documentLibrary/med ... _Chg_2.pdf

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Indranil » 28 Nov 2018 21:52

Lalmohan wrote:as in I am sure that 100kts is well below stalling speed in any flight regime for this type of airframe configuration... there must be some other explanation for what it applies to

Lal Mullah, 100 knots is above the stall speed. FCS of LCA doesn't allow for the aircraft to stall as recovery is very tricky for such an unstable platform (Pretty much on the lines of other modern fighters).

100 knots is limit set for the automatic low speed recovery system. This was one of the outstanding FOC aspects for carefree handling. At 100 knots, the FCS takes over, recovers the aircraft and hands it back to the pilot. They started testing this last year. They initially wanted to set the limit at 120 knots. When they went into testing, they found that they can go much lower. So they went back to fine tune the FCS. Now, they have set it to 100 knots. This is a testament to the FCS and the simple airframe design. This is the limit set for the Mirage 2000, and Gripen C/D. But Gripen floats its canards at this point (making it a stable platform). The lowest that I have read (on forums) is 85 knots for the Rafale. But 100 knots is very very very respectable.

What it does for the envelop is stretch it. As you know the envelop is like a sheet, if you pull one corner a lot of new area gets inside the envelop. It is not about what is the use of flying 100 knots. This basically allows the FCS to the lower bottom speed of every aspect of flying the LCA.

SaiK wrote:recovery after stall threshold?

No sir, no stall involved. The ALTS basically allows the pilot to now go closer to stall speed in a carefree manner.

nam wrote:I don't know what 100kts will be used for, however it tells me the great intake design and FCS we have. The engine is not starved of air and FCS is able to keep the jet in air.

We can't infer anything about the intake design here. Intakes work at 0 kts. 0 kts or 100kts are definitely some ways away from the "design point", which is typically about 350-400 knots. The question is what is the drop the efficiency at 100 knots. That, we don't know.

nam wrote:I can do a wild guess, one of the things this will help in reduced landing speed? Helping in a way to NLCA?

Yes, it will help there. Although, they are not trying to do that. They have achieved the landing speed they desired. They want to increase the sink rate from what they just concluded testing. Currently, they do not see a reason to change anything. They are testing in a progressive manner. At the next Goa outing, they will test at the desired sink rate. Once they have done that, they will try a live trap at INS Hansa. Once these are cleared, LCA will be cleared to land on VikAd.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Haridas » 28 Nov 2018 22:10

ramana wrote:Kartik, Whats significance of 100 knots? Isn't it too low a an airspeed?

Imho essentially would allow lower permitted landing speed that is safer for pilots & less stressful on airframe, not to mention abelity to land on runway with heavier all up weight ( without requiring jettisoning all unused weapon & fuel / tank).

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Karan M » 28 Nov 2018 22:22

Rakesh wrote::lol: (laughing at the IDRW bit!!!)

Lalmohan Saar, just take the tidbits that IR gives and do a lungi dance. IR is not one to embellish.


Exactly. He goes to incredible lengths to get the info and gives the developers their day in the sun. Let's just be happy, the information is appearing from someone credible and smart enough to parse the details, for us folks and sharing it!

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Lalmohan » 28 Nov 2018 22:32

thank you gentlemen - I mis-spoke, when I said source, I meant the explanation that indranil has provided
I don't want to know the chai bagan where it came from

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Kartik » 28 Nov 2018 23:47

ramana wrote:Kartik, Whats significance of 100 knots? Isn't it too low a an airspeed?


It allows for significantly reduced landing speed for one and also means that the Tejas Mk1 will be controllable even at the low speeds during a dogfight..when energy is lost due to maneuvering.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby nam » 29 Nov 2018 00:00

With HMCS and today's CCM, I don't think there will be too much scope of old fashion dog fight, specially energy bleeding manoeuvres.

However given LCA's size, I always wonder if LCA can be easily spotted by HMCS. It is difficult to spot with naked eyes even at a airshow.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby ramana » 29 Nov 2018 00:18

thanks all for the learning we get here.

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Karan M » 29 Nov 2018 00:26

nam wrote:With HMCS and today's CCM, I don't think there will be too much scope of old fashion dog fight, specially energy bleeding manoeuvres.

However given LCA's size, I always wonder if LCA can be easily spotted by HMCS. It is difficult to spot with naked eyes even at a airshow.


HMS + CCM are particularly useful for nose pointing fighters, i.e. those with high ITR. The classic STR kind of dogfighters are inconvenienced by the "one look one kill" basis as the entire logic behind a constantly turning fight is lost.

LCA by virtue of its delta planform is exactly the high ITR kind of fighter which benefits most from the HMS + CCM combination. Unlike the Su-30 it has a fullblown HMS. The pilot need not look down at his instruments while making the shot.

Similarly, the Su-30 MKIs are able to achieve phenomenal ITR via TVC, and that coupled with HMCS and CCM makes them deadly. And the Su-30 MKI has two sets of eyes and two HMCS helmets!

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Indranil » 29 Nov 2018 00:30

nam wrote:With HMCS and today's CCM, I don't think there will be too much scope of old fashion dog fight, specially energy bleeding manoeuvres.

People have been saying that for the last 40 years. It is a cat and mouse game. :wink:

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby Karan M » 29 Nov 2018 00:42

When you are out of missiles, then the dogfight game comes back into full play!

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby SaiK » 29 Nov 2018 01:12

better to return for reload.., and of course dogfight only to get a laser boresighter to go gatling !

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Re: Tejas Mk.1 & Mk.1A News & Discussions: 09 February 2018

Postby souravB » 29 Nov 2018 01:17

Saw this in Twitter. This is according to HAL CMD on his latest interview. This comes in as $84M per unit by my sabjiwalla math. Hope it also include lifelong support package from HAL otherwise the price is unjustifiable if we are also looking for export.

https://twitter.com/__not_a_bot_/status ... 5581064193 ---> 50000cr 83lca mk1a order likely to be done finalised by mid next year: HAL


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