Monday, February 09, 2015

PART 1: Big Surprises In LCA Navy NP1's Ski-Jump Fight

When the first prototype of India's LCA Navy (NP1) roared off the ski-jump at the Shore-based Test Facility (SBTF) for the first time on December 20 last year, no one from the team observing the jet from the flightline and from telemetry stations knew that something unseen had happened. Something that would only become known later in the day when performance data was analysed. And it was good, solid news, much needed for a team that has seen little more than questions, derision and barely veiled bemusement. Importantly, it was the first time the team felt it had an answer to the 'what use is this platform, really?' question.

The NP1, which had flown for the first time in 2012, had remained mostly on ground for the next two years, undergoing an extensive undercarriage re-design. In 2013, it climbed cautiously back into the air before going supersonic last year, and finally getting set for a shot off the simulated shore-based carrier deck in December 2014.

According to sources on Team LCA-N, "For a ski jump launch, the final design intent is to have a zero rate of climb after ramp exit to get the best performance of the aircraft.  This places a great premium on the ability to fly at the maximum possible angles of attack with adequate control and also to have a complete understanding of the thrust available."

And that's where it gets interesting.

Top sources on the team say the NP1 was flown a few times conventially before the ski-jump test to soak up the thick sea-level air in Goa. As expected, engine performance was markedly better. Spirits were high, but as has become the norm on milestone tests in the Tejas programme, there was pervasive nervousness. Surprises can be nasty. And the ski-jump test would leave no recovery time if something went wrong. As the Team says, "The first attempt at any new activity is fraught with uncertainties and potential surprises. Given the 'leap off the edge' nature of the first launch, all the major possibilities of failure were identified and options to handle them were built into the plan."

The test flight team decided to lock 5.7 degrees as the minimum climb angle for the NP1 once it made the leap off the ski-jump. When the aircraft actually did roar into the sky, the actual minimum climb angle was observed to be in excess of 10 degrees. Also, the NP1 achieved an angle of attack after ramp exit of 21.6 degrees, giving the team healthy new margins to work with in terms of performance. Simply put, the aircraft performed better than the team ever thought it could.

Now you can argue that safety margins always allow for bumps in performance, but the number crunch that evening demonstrated that the NP1 had exceeded expectations healthily.

The test team's verdict: "This is certainly a welcome bonus for an aircraft that has been so often derided for lack of thrust, and this excess will be accounted for in future launches. Also the angle of attack after ramp exit reached 21.6 degrees which augers well for utilisation of even greater angles of attack for launch. It should certainly allay fears over the use of such high angles of attack and remove much of the pessimism that has surrounded the utility of the programme."

The NP2 single seat naval fighter prototype that took to the air yesterday will join sea-level flight test next month and quickly demonstrate its own carrier compatibility before long. The LCA-N team, in the meanwhile, has its spirits up. The Indian Navy, which has ordered six of LCA Navy Mk.1 has indicated, albeit unofficially, that the Mk.1 platform is likely never to see actual carrier service. While the performance surprises of December aren't likely to change that, the numbers have changed. And that's something.

Tomorrow: The Four 'Fixes' After LCA Navy's Ski-Jump Flight


Anonymous said...

@singam - Very interesting analysis. Given the nature of doing something like this for the first time, I can understand the apprehensions and nervousness. Ski-jump take-off data inputs from the plane also give ADA a bigger envelope to work with.

Even though these are small steps, but the valve on what is being learnt is immense.

Shiv, very informative article and great insight. Thank you for putting this together and sharing the same.

Anonymous said...

Is the weapons carrying ability of this aircraft comparable to international standards ?

Anonymous said...

Several question:

Are you sure that 21.6 is AoA and not pitch? At ramp exit and following it, the plane has a positive climb. In such a condition pitch ~= AoA + climb/horizontal-speed.

Also I'm not sure that surprise in 1st ski-jump testing is "good thing" because it means that simulations that were performed aren't good.

Anonymous said...

Do you talk the way you empty your bowels

Anonymous said...

With all the twists and turns of the intriguing pot-boiler thriller, it would not be a wild assertion that the Naval version of the LCA may end up being a run away success ! Heck in its MK-II avatar, it might see deployment from a carrier deck before the IAF's version, attributable to the fact that the Indian Navy has always been a more engaged and involved partner in its development.
Contrast that to the knuckle headed, frat-boyish approach of the IAF which never believed nor wanted to be party to an indigenous fighter development program.
It would therefore be befitting for the MoD to whip the IAF frat boys into shape by cancelling the MMRCA RFP and make them swallow humble pie and drag them by their ears to the table and re-engage on the LCA MK-II project like never before !

Anonymous said...

Anon @ 2:11, please don't display your amateur wannabe status to such a ridiculous extent on this forum.
The work on the Tejas is a team effort, and both the IAF and the Navy (the actual services, not the Jingo assumptions of these entities) are both heavily committed to the project.
The IAF has placed an order for 40 aeroplanes, and wants a product that works as advertised in order to meet their responsibilites to the nation. Please do not trivialise the efforts of ADA, HAL, the IAF and the IN by letting fly with ignorant rants about how things work in D&D of major weapon systems.
In conclusion, you of course have the right to be as much of an armchair enthusiast in this and other fora as you wish, but you only display your immaturity with your comments. Unless you put your money where your mouth is, i.e. sign up and put yourself in harms way, you would be well advised not to be so quick to insult those who are actually putting their lives on the line.

Balaji said...

Will try to answer the queries / comments:
1. It certainly has been a tremendous input giving the design teams a wealth of information and confidence for further activity
2. 21.6 is AoA and not Theta. We had done tests up to 23 AoA as part of lead up tests

Anonymous said...

Folks ,

Good news is always welcome . But we already have enough Mig 29's in the navy . What is the LCA's role except that of a supporting actor ? Navy is for the sea - so instead of diverting our attention from lack of submarines and advanced boats the Navy should go all out for submarines with a single minded purpose . Our neighbours realised this long ago and have concentrated on steadily upgrading their fleets . Indian Navy , like the airforce , might soon become more of a coast guard than an effective blue water force . This is not a rant but my two bit in respect of the tragedy unfolding before our eyes.

Anonymous said...

Thanks for the info I wish the stealth and endurance could be increased in MK2 for IAF and Navy and the inlet needs to be redesigned in order to help the F414 and also keep the the aircraft stealthy just like Rafael

Anonymous said...

ANON @ 4:28 PM
Boy did that touch a sensitive nerve just I had hoped it would ! Listen, every pragmatist knows this well enough
as much as you do, that the time has come to rid of the sacred cows in the Indian defence establishment if we are are to move forward and bring about an a measurable improvement in our indigenous capabilities to plan, design, develop and deliver systems. That includes reforming the way ADA, DRDO & HAL operates. In the same breath it also calls for a massive realignment in the way the service arms plan, strategize and operate.
Just because someone chooses to put their life on the line by enrolling in the services does not give that person more say in the matter. There are people in this country that are contributing in equal measure in their respective spheres of expertise. It doesn't make their efforts any better or less significant. You consider yourself an expert, but a blogger does not make an expert.
I have great faith in the new MoD. He is no-nonsense guy who stands ready to strip every sacred cow there is in the current Indian defence establishment, naked, if that's what is needed to drive and deliver systemic and long-lasting change.

Ajai Shukla said...

Very interesting piece, Shiv! Thanks, Ajai Shukla

Shiv Aroor said...

Thank you Ajai!