HAL Tejas | Updates, News & Discussions

[Neo]

F-16XL - AFTI

 

[joey]

Thanks neo for the information Neo, the linkage with voice-controls and VTAS is interesting indeed.

Here is another very interesting algorithm, I wonder if it will be integrated in LCA,

iirc LCA will have carefree handling along its 3 axis and 6 degrees of freedom, I wonder if this algorithm will help it to achieve better results

One can do two simple things to prevent deep stall,

1> Prevent your ac from being stalled using sensors/carefree handling along all its three axis and 6 degrees of freedom.
2> Recover it from stall.

Recovering Aircraft Safety after Loss of Pilot Control: An Innovative Algorithm
N Ananthkrishnan, Department of Aerospace Engineering


Over the recent years we have witnessed frequent media reports on crashes of military aircrafts in our country. Such incidents do keep recurring globally in peacetime. Crashes could be due to various causes: bird hits, mechanical defects, bad weather, etc. However, recent statistics have shown that a large number of crashes are due to a specific problem faced by pilots called spatial disorientation (SD).

When flying difficult sorties and under poor weather conditions, pilots can be confused (disoriented) about which way they are heading (up or down), and whether the ground is below their feet or above their head! For example, military pilots are known to suffer from visual illusions during night flying such as mistaking discrete ground lights for the stars and consequently flying inverted (upside down).

A recent study has shown that almost 90-100% of aircrew have reported at least one incidence of SD during their flying career. Pilots either fail to recognize an SD condition and hence take no corrective action or, even when they recognize the problem, are too disoriented to be able to recover the aircraft to safe flight. In most cases, the aircraft ends up in what is called a spin or a spiral dive with the pilot having no control of the aircraft – the airplane nose drops, it starts going around in circles while losing height rapidly.

Spatial disorientation is a problem that can confront any pilot, no matter how highly experienced and well trained. During the years 1980-89, the US Navy reported 112 major accidents, and the US Air Force reported 270 major accidents, involving SD and loss of pilot control. Pilots of general aviation (light) aircraft are equally vulnerable to SD - one of the more high profile crashes was that of the Piper Saratoga being flown by John F Kennedy, Jr. on July 16, 1999. Unfortunately, many accidents caused by spatial disorientation are wrongly labeled as due to pilot error.

To avoid loss of costly airplanes and to save precious human lives, a two-pronged strategy has been suggested in the literature:

Pilots should be trained in flight simulators to recognize SD situations and hit a Panic Button provided in the **** pit
The aircraft's automatic flight control system should have a Panic Button Algorithm that takes control of the air plane from the pilot and recovers the airplane to a nor- mal flying condition.
However, developing an effective Panic Button Algorithm has been a challenge because of the tight constraints involved: pilots will usually hit the button only when they are in a hopeless situation with the plane already hurtling to the ground, and the algorithm must respond in a very short time before an imminent crash.

The New Algorithm
In a major breakthrough, researchers at the Department of Aerospace Engineering, IIT Bombay, working over the last 3 years (2002-04), have come up with a novel Panic Button Algorithm that seems to meet the challenges pointed out above. The research team consisted of students (P K Raghavendra and Tuhin Sahai, P Ashwani Kumar), a research assistant (Manan Chauhan), and the author. The work was partly funded by the Aeronautical Development Agency (ADA), Bangalore.

Using a combination of two sophisticated new methods called Nonlinear Dynamic Inversion (NDI) and Extended Bifurcation Analysis (EBA), the team from IIT Bombay has devised a unique Panic Button Algorithm that successfully recovers an airplane from even the most adverse flight conditions. The crux of the present work lies in recognizing that a successful algorithm must use a two-step approach where it is necessary for the airplane to pass through an intermediate (waypoint) state before it can be properly recovered to a safe flight condition.

The research team has carried out extensive computer simulations using high-fidelity aerodata obtained from NASA for a specially modified F-18 airplane called the High Angle-of-Attack Research Vehicle HARV (see illustration) to establish the effectiveness of their algorithm. In the future, the Panic Button Algorithm could be built into sophisticated Flight Control Systems being developed for advanced combat aircraft such as 'Tejas' the Indian Light Combat Aircraft (LCA). Interestingly, their work also shows that aircraft equipped with thrust vectoring (TV) engines, such as the Sukhoi SU-30, have a 60 per cent better chance at successful recovery as compared to aircraft without TV capability. Translated in terms of height from the ground, airplanes with TV can be recovered after loss of control at much lower altitudes, which is important since nearly 100 per cent of loss of control cases at low altitudes presently end up as crashes.

Presented at the Aerospace Sciences Meeting organized by the American Institute of Aeronautics and Astronautics (AIAA) at Reno, NV, USA (Jan 2004), the work has been appreciated internationally for its thoroughness and novelty. It is expected to be of high value to the international aircraft design community.
http://www.ircc.iitb.ac.in/~webadm/update/Issue1_2005/algorithm.html

Aeronautics
In aerospace labs from Bangalore to the US, an Indian idea to save combat aircraft is making experts sit up and take notice.

Prof. N. Ananthkrishnan doesn’t panic every time his office building at the Indian Institute of Technology (IIT), Bombay, shakes violently and the steel almirahs rattle. It’s only a colleague at the lab next door flying toy-size aero-planes and spares—like a Concorde wing replica—in a wind tunnel where air blazes in at thrice the speed of sound. But the bespectacled Ananthkrishnan, 1989 batch, IIT Bombay, prefers F-18s, avoids cellphones and is not scared of plane crashes—at least not on his computer, where he’s at the controls. After digging into math and software codes from 2002, Ananthkrishnan, his three students, all about 22, and a research assistant have proven—in computer simulation on F-18 data sent from NASA—a Panic Button Algorithm to recover combat aircraft that may be spinning to a crash.

This is a piece of work that aviation’s top guns, the American Institute of Aeronautics and Astronautics (AIAA), and Bangalore’s Aeronautical Development Agency (ADA) have followed keenly and are now taking very seriously. The IIT algorithm has the intelligence to recover military aircraft from a loss-of-control spiral or spin to safe mode—theoretically, even if the pilot hits the panic button about 20 seconds before an imminent crash.

“Five years ago when a top Indian Air Force officer suggested this topic to me, nobody in India was working on this,” says Ananthkrishnan, associate pro-fessor, aerospace engineering. “We expect that our algorithm can be built into automatic flight control systems being developed for present-generation combat aircraft like the Light Combat Aircraft (LCA) Tejas.”

This November, the research, partly ADA-funded, was published as a paper in the AIAA’s Journal of Aircraft. The reviews spoke of going beyond the lab: “Both the methodology and the findings... are relevant and of value to the aircraft design community,” said an expert review. At the ADA, they have kept a keen eye on the idea. “As higher computational speeds will be available in future, we could use the IIT algorithm in the next LCA version, directly,” says P.S. Subramanyan, ADA director and also programme director (combat aircraft). “For now, their research has given us clues for our experimental LCA stage, to recover it from spin at high angle of attack.”

Agrees K.V.L. Rao, ADA’s technical advisor: “This new technology will be very beneficial to fourth-generation aircraft like the LCA (Tejas) currently under flight testing at ADA.” Such aircraft, Rao explains, are designed to be unstable for better agility and combat effectiveness. “At high angles of attack beyond stall, the aircraft can lose control and get into a spin,” says Rao, adding: “LCA has a flight control system to prevent such departure leading to spin. However, aircraft has to be tested for recovery from spin during flight test phase. The panic button concept would enable aircraft to recover to safe flying mode.”

A falling aircraft can plunge 300 feet per second. “There are barely 20 sec-onds to act before a crash,” says Ananthkrishnan. So the team first computed all possible conditions for loss of control and also to recover the aircraft. They used two codes or tools: one called the Extended Bifurcation Analysis made in-house by a PhD student four years ago, and a non-linear dynamic inversion software. The algorithm aims at the spatial disorientation (SD) pilots suffer during military sorties: for example, visual illusions during night flying or adverse weath-er conditions when pilots can get too disoriented to recover the aircraft in time.

SD was blamed for John F. Kennedy Jr’s Piper Saratoga crash in 1999. “Now that we’ve tested the algorithm to work in the lab on realistic aircraft data, the next step would be to test it on real flight control systems,” says Ananthkrishnan. “That could be years away.” P.S. Meanwhile, Ananthkrishnan’s young engineers who also worked on the flight plan have flown away to Cornell, Princeton, Michigan and Chicago.


—Reshma Patil
http://www.aero.iitb.ac.in/~akn/panic.php.html

 

[joey]

Finally I know something you don't know...yay!

lol ,

"I'm just picking up the pebbles in the beach, there is whole sea left ".

anyways I knew about F16XL not the AFTI programme, didnt took much interested in the FBW which we had to re-design anyway and it proved to be better as per chief scientist who designed it.

 

[con]

LCA to fly in Paris Air show.

http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=8775

Check out the entry which says:
HAL LCA Tejas


I say Coool

 

[Bull]

Rafael has been selected to supply its Litening targeting pod to equip the Indian air force's Aeronautical Development Agency-built Tejas light combat aircraft.

The order - of undisclosed value - covers the production of Litening systems for the service's initial batch of 20 production aircraft.

Defense Update:
LITENING incorporates in a single pod all the targeting features required by a modern strike fighter. The LITENING program, launched by Israel's Research and Development authority RAFAEL in 1992, combines multiple sensors for maximum flexibility in a single pod at low cost.

The original pod included a 1st Generation FLIR, a TV camera, a flash-lamp powered laser designator, laser spot tracker for tracking target designated by other aircraft or from the ground, and an electro-optical point and inertial tracker, which enabled continuous engagement of the target even when the target is partly obscured by clouds or countermeasures.

The HAL Tejas is an advanced, lightweight, supersonic multirole fighter aircraft being developed by India. It is a tailless,[1] compound delta wing design powered by a single engine. Until the aircraft was formally named (by then Prime Minister Atal Bihari Vajpayee) as Tejas on 4 May 2003, the project was known as the Light Combat Aircraft (LCA), which continues in popular usage.

Limited series production of the Tejas has commenced in 2007; it is currently projected to achieve limited initial operational clearance (IOC) with the Indian Air Force (IAF) by 2008, followed by full operational clearance (FOC) by the end of 2010.[4] A naval variant capable of operating from the Indian Navy's aircraft carriers is also in development.

As of 26 May 2007, the LCA had completed 672 successful test flights in all (TD1:207, TD2:258,PV1:135,PV2:28,PV3:38,LSP1:6).

 

[Bull]

joey, Neo throw some light on this.

 

[joey]

On what bul, oh that Litening pod on LCA? it means only one thing, LCA is going to be used as potential a2g from start

Mig 27/MKI/Mirages and i think jaguar as well is equipped with these pods, If i remember carefully LCA has one hardpoint extra just for using pods.

 

[Samudra]

LCA to fly in Paris Air show.

http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=8775

Check out the entry which says:
HAL LCA Tejas


I say Coool

If things go according to the plan I will be in Paris to see the Tejas fly.

EDIT : Nopes. Not possible this time.

 

[Neo]

LCA to fly in Paris Air show.

http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=8775

Check out the entry which says:
HAL LCA Tejas


I say Coool

Tejas and Dhurv both will fly at Le Bourget.
I'll try to take a few nice pics for you guys.

 

[Neo]

If things go according to the plan I will be in Paris to see the Tejas fly.

EDIT : Nopes. Not possible this time.

Why not...?
Munir, I and a few other friends will be there aswell.

 

[joey]

Neo get your best SLR or whatever camera (we poor chaps here in india cannot even afford a decent SLr ) and do get some good pics, I wonder if the PV-3 will fly or the LSP-1.

Is that only airshow or airshow cum aerospace exhibition like that happened in AERO India?

 

[EagleEyes]

F/A-22 and JF-17 will be missing. Darn it.

 

[Samudra]

Why not...?
Munir, I and a few other friends will be there aswell.

Wish I could...lets see how things go.
I'll make the decision a week before - around 15/16th of this month.

 

[Neo]

The event will take place between June 18-24, we'll be there on 22 and 23rd.

 

[Neo]

If you don't make it to Paris Le Bourget there's another big one in Farnborough in UK, the next on my list depending if Munir is going.