LCA TEJAS MK1 & MK1A: News and Discussion

[Assassin 2.0]

yes I'll stop.

yes I'll just stop....

Yeah bc Chinese puri duniya m virus bhej k chill kr rhe h porki bc jihad krke ki bc maje le rhe h unhe ghanta farak nhi padh ta kon kya keh rha or hum yeha p bina kisi k kand k dusro k chutiyap opinions p apna demag khrab kr rhe h.

 

[vishnugupt]

The max gee occurs at 15 deg AOA or so if going fast enuf, then the gee decreases to approx 1 gee at 25 deg AOA, regardless of how much you are pulling on the pole.


The 25 deg AOA limiter was intended to allow a super turn rate without bleeding off a lot of energy. Further, the pilot did not have to worry about pulling too hard at slow speed, as the jet would give you its best, and you could concentrate on tactics, looking around, etc.

The most important thing to remember about AOA is that the amount of lift the aircraft is producing is roughly proportional to the angle of attack times the square of your airspeed. What this means is simple - if you are flying slow, you will need to maintain a higher angle of attack in order to keep the airplane in level flight. If you maintain a constant angle of attack while slowing down, the aircraft will begin to descend. Likewise, if you maintain an angle of attack while speeding up, the aircraft will begin to climb.

All wings have what is known as a "critical angle of attack". If the critical AOA is exceeded, the aircraft will "stall" - the airflow will separate from the wing and become turbulent, preventing the wing from producing lift, and the aircraft will begin to fall (as in "fall like a rock", not "descend like an airplane"). The ONLY way to recover from a stall is to reduce the angle of attack by increasing power and pushing the aircraft's nose down. If you pull back on the stick or allow the stall to continue, the angle of attack will continue to increase, deepening the stall and making it more difficult to recover. Eventually, you will end up in a "deep stall" where the aircraft is essentially falling straight down. These are extremely difficult to recover from.

The flow visualization of Sukhoi Su-30MKI like-model using GAMA water tunnel has been conducted to investigate the vortex dynamics on canard and main wing. This work aimed to observe the aerodynamic force and the vortex-dynamic phenomenon. The water tunnel is an effective visualization method to determine the vortex-dynamic phenomenon which was used in this research. The usage of water tunnel would make it easier to reveal the phenomenon that occurred. The results of GAMA water tunnel experiment showed the aerodynamic force and vortex dynamics phenomenon on the model of Su-30MKI aircraft. The increasing of lift force was started from a small angle of attack (AoA) to a maximum value at an angle of 45 degrees. The maximum lift value on the test using GAMA water tunnel was about 1.38. The vortex dynamics have been particularized using observation of vortex core formation and vortex breakdown location. The higher of AoA caused unstable vortex core flow so that the vortex breakdown location would lead to leading edge.

Source :

file:///C:/Users/panda/Downloads/Vortex_Dynamics_Study_of_the_Canard_Deflection_Ang.pdf

Thanks for explanation
So 25 degree AOA is a limiter for most of the aircraft, including Tejas. Could you please explain the manoeuvrability aspect of AOA like Su30MKI can achieve/sustain very high AOA, How much Tejas can achieve ??

 

[fire starter]

Thanks for explanation
So 25 degree AOA is a limiter for most of the aircraft, including Tejas. Could you please explain the manoeuvrability aspect of AOA like Su30MKI can achieve/sustain very high AOA, How much Tejas can achieve ??

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[vishnugupt]

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Actually I was asking in a different aspect, manoeuvres like these in videos
I witnessed this very Su30MKI manoeuver on Republic day. it took barely a few meters to SU-30mki to turn 90 degrees. Does Tejas have the same capability ??

 

[Indx TechStyle]

It was quite painful because deep down i know whatever they said about us indians is true.

Not most of time. They even use incorrect pictures, deliberately misinterpret press released information and move to even name calling.

I left because I don't want to waste time. Not because I couldn't fill pages with arguments.

forget about china we can't even deter pakis,

We have came close to wiping them out of map at multiple points of history. Most recently just one year ago.

and last years incident completely destroyed our image world over.

It didn't. If you even have an iota of knowledge of military equipment, doctrines etc. it didn't.

Engagement with a full squadron of 21 planes against 8 grounded planes and even then ending up getting chased on LoC in an F-16 by a MiG-21 and that this is "retaliation" against a full deep strike? My foot.

It is same as that Pakis with 3 reactors compare with nuclear program of India (27 reactors, and of different kinds), much higher R&D or missile tech (39/94 of defined missile techs by Pakistan, 85/94 from India).

I can't help selected foolish journos and fanboys who are just used to get thrilled with India vs Pak drama and compare the two countries.

Yes but it's painful.to see china making all the right decisions and our foolish decision makers making all the wrong choices be it mmrca p75i...chinis didn't even have single aircrfat carrier couple of years ago...and today they have 2 and 3rd in making and then we have our vikrant sitting at the same place for more than 10 years....ideally we should just cancel mmrca contract and build up our force multipliers AEWCS, jammer aircrafts,ELINT in very large quantities....

Not actually very right decisions but luck. They had luxury of US support (heard of Laurel satellite scam) which is basis of their entire aerospace industry what wasn't enjoyed by India.

 

[WARREN SS]

Could you please explain the manoeuvrability aspect of AOA like Su30MKI can achieve/sustain very high AOA, How much Tejas can achieve

Report By

AN APPROACH TO HIGH AoA TESTING OF THE TEJAS LCA
Wg Cdr VIKRAM SINGH
National Flight Test Centre, ADA
https://www.scribd.com/doc/78345390...g-of-Light-Combat-Aircraft-LCA-Tejas#download


LCA Tejas Testing has traditionally progressed from approach to stall maneuvers through full stall series to spins and stalls with aggravated inputs.
This approach to testing has evolved significantly with the introduction of highly
augmented flight control systems in increasingly maneuverable aircraft through
decreased stability. Advances in control system technology and to a lesser extent,
aerodynamic design, have led to a shift of emphasis from investigating post stall
behavior and recovery to prevention of departure in modern combat ac. The fly-by-wire
flight control laws resident in the Tejas LCA, in addition to providing the basic command
and stability augmentation functions, will also include departure prevention through
boundary limiting / carefree maneuvering features to enable the pilots to fully exploit the
capabilities of the airframe. The departure resistance features in the control laws also
maximizes the useful angle of attack range of the aircraft while maintaining adequate
levels of stability. Provision of a boundary limiting function in the control laws in the
initial phase of flight testing does not guarantee that the aircraft will not depart during
large amplitude maneuvering since the aerodynamic data used for control laws design
are based on wind tunnel data which can exhibit different characteristics in flight
especially at higher angles of attack where the data is highly nonlinear.

LCA has been designed to be aerodynamically
unstable in the longitudinal axis to obtain improved maneuverability and agility over the
entire flight envelope and hence, has to be stabilized artificially by the use of active
control technology. The flight control system is a digital, quadruplex redundant full
authority system exercising control through two sets of paired elevons and a single
rudder. The stability and control cycle is updated every 12.5 milli secs through high
fidelity, rate and acceleration sensors and high rate control actuators. Tejas instability is
defined by ‘time to double amplitude’ and is one of the lowest amongst contemporary ac
in the world. Graph at Fig-2 depicts this value across a Mach vs altitude scale. The
region from 0.5M to 0.7M and from 3Km to 8 Km is the zone of the highest instability
with time to double amplitude dropping to 200 milli secs. This implies that any
disturbance in pitch would cause an increase in amplitude by 32 times in a sec.

CL Max And Usable Aoa Considerations. Wind tunnel experiments have
indicated that CL max continues to improve till approx 35 AoA as shown at fig-3.

However, directional characteristics indicated the proverbial ‘cliff’ with a sudden drop in Cn
, CRM (Coefficient of Rolling Moment) and CYM (Coefficient of Yawing Moment) atapprox 25
AoA as shown at fig-4 and 5. These phenomena require the High AoA trialsto be limited to 24

(as shown in dotted line) until directional stability is bolstered andaugmented by rudder control up to an expected 26. Currently the Tejas is flying to AoAlimits of 20 and 22
never exceed. Fortunately as shown in fig-6, the LCA hassignificant rudder authority (CYM-Del R) even up to 30
AoA that will allow artificial stabilization in yaw at high AoA


Read Full Report to End you query

 

[IndianHawk]

It was quite painful because deep down i know whatever they said about us indians is true. We fucked up big time, all those precious years of 90s, all those opportunities wasted and theres no way we can catch up with china now.

Lmao. China is screwed dude. Those idiots at ccp have destroyed Chinese birth rate . Now chinese future is old men in diaper's. Lol.

Yes but it's painful.to see china making all the right decisions

What right decision china made? Those morons copied failed su33 for naval aircraft and now j15 is a dud so china effectively has no carrier air wig. Lol.

4 have crashed out of 20+ builds worst plane ever. LMAO . And that what is in open God knows how many crashed in secret.

Stop believing bullshit of sinodefece . Those are brainwashed ccp trolls. None of them have even an iota of intellect that many members here project.

And there are no American or German on sinodef. They are all chini flase flagers. Lol.

Read the forum and learn the truth of Chinese greatness.

You should have visited sinodef at the time of doklam oh the howling. A lot of them were going to commit suside out of the embarrassment of how India treated china. Lol.

 

[IndianHawk]

I registered already...............

Ask them when they are taking Taiwan back ! And tell them to shut up till then .lol

 

[IndianHawk]

I used to post there but they always used to make an issue out of non issue and always used to try to me shut me up showing up their numbers. This insecurity doesn't make any difference to me.

2 years ago, I left it forever for better.

Those braindead indiots can't even accept that ccp is the same ccp which killed millions of their own . No point debating them . Just treat them like braindead slaves that's the recommended way to treat Chinese by ccp. Lol. I support ccp.

 

[Aniruddha Mulay]

It was quite painful because deep down i know whatever they said about us indians is true. We fucked up big time, all those precious years of 90s, all those opportunities wasted and theres no way we can catch up with china now....forget about china we can't even deter pakis, and last years incident completely destroyed our image world over.

This guy seems to be from the Pravin Sawhney camp

 

[Aniruddha Mulay]

This guy seems to be from the Pravin Sawhney camp

Deep throating chinese micro dicks whenever and wherever possible.

 

[scatterStorm]

F-16 Max. angle of attack is 25AOA,

Correction at 9G at 26 degrees.

 

[Saichand K]

No. It is 9G at 25.5 degrees AoA.

Correction at 9G at 26 degrees.

 

[scatterStorm]

We got a few clarifications from video
1) No OBOGS
2) Gun is there but not operationalised. Firing will take place later on from SP21
3) Air refuelling time: 5 minutes 30 seconds without drop tanks
4) maximum AOA is 24 degree ( Any genuine opinion is welcome ?)
5) If the production of LCA increased from present rate ( 8 per year ) there will be a gape b/w Mk1 and Mk1A
6) Faulty quality production was a beggest lie perpetuated against HAL. In fact, production quality is A class
7) Quick turn around time after each shorty which means low maintenance. there were rumours that it take LCA 1-week maintenance after each shorty ( Before Gaganshakti )

Max G limit of 8G but can go more, however its onboard flight controller would only allow it go that. I don't know if it can be manually shut like F16 or F18 does. If it can, you can go 26 too if at 9G, as also mentioned by @WARREN SS that it can go up to 30 degrees but that would be suicide.

JF17 at max 8G has 26 degress of AoA. You can confirm this it even in DCS combat flight simulator too.

 

[scatterStorm]

No. It is 9G at 25.5 degrees AoA.

At 9G you are basically disallowing its flight computers to control its STR. You can go 26 too, that is confirmed by F16 and F18 hornet pilot C.W Lemoine, when the PakF16D mishap happened.

 

[scatterStorm]

So its true than ...

 

[Karthi]

Fan art of Naval LCA

 

[Karthi]

Aviation Cockpit Display Validation Platform - ACDVP. Old picture

 

[Karthi]

Boresighting System designed for LCA Air Force. Old picture

 

[Narasimh]

Tejas Titans: Tarmak Talking with superheroes of HAL's LCA Division

Can somebody clarify what did the good Air Cmde mean by "we are carrying the mid-board pylon for the first time" (spot at 10:22)? Midboard pylon was there before isn't it?