Dr. Shyam Chetty was the Former Director of CSIR - National Aerospace Laboratories, Bangalore, and held additional responsibilities as Director CSIR-4PI, Bangalore, Project Director of the National Control Law team for LCA, and Chairman of the Systems Engineering Cluster of NAL. He has over 40 years of experience in the field of Aircraft Flight Mechanics & Control. His research interests include Flight Control System Design & Development, Aircraft Simulation & Modelling, Handling Qualities & Aircraft Pilot Coupling, Computer Aided Flight Control Design & Rapid Prototyping Techniques.
He also has the distinction of having served as the Chairman / Technical Expert of Review Committees on most of the Major National Aerospace Programmes of ISRO, DRDO and ADA. He has won several awards, prominent among them being the Jawahar Lal Nehru Memorial Award in 1976, Sir C.V. Raman Distinguished Young Scientist Award in 1998, DRDO Award for Path Breaking Research in 2002 and many more.
CSIR-NAL has also provided significant value-added inputs to all the Indian national aerospace programmes. Its contributions over the last five decades have enabled it to create a niche for itself in advanced aerospace research and technology development.
Question 8: The CLAW team led by NAL together with NFTC, ADA evolved safe and robust procedures for Ski jump launch of the LCA Naval variant and successfully demonstrated this during December 2014 from the shore-based test facility at Goa.
How was the development different of the Naval Variant of the Aircraft compared to the Air Force versions?
Takeoff and landing from the ship deck is very different from takeoff and landing of an airforce variant from a normal runway, this is mainly due to the very short deck lengths available on the aircraft carriers. The LCA airforce variant needs a minimum of 600 to 800 metres for normal runway take off and landing, however only about 150 to 200 metres are available for ramp takeoff and about 50 to 100 metres for arrested landing on a ship.
Two approaches are adopted by industry to enable naval aircraft to take off from the ship deck in spite of their shorter lengths.
In the first approach a high pressure steam propelled catapult is used rapidly accelerate the aircraft to speeds required to generate adequate lift for wing borne flight immediately on leaving the shipdeck.
In the second approach a 12 to 14 degree parabolic ramp is added to the trailing portion of the shipdeck to propel the aircraft in an upward ballistic trajectory. To start, the aircraft is held in position using hydraulically operated chocks for the main landing gear wheels, the engine is revved up to the maximum afterburner thrust and then the chocks are lowered allowing the aircraft to accelerate over the ramp.
The curvature of the ramp is designed to propel the aircraft in an upward ballistic trajectory on leaving the ramp edge and then the pilot is required to operate the controls in a manner to increase the angle of attack thereby ensuring that the flight path is always positive and manipulating the energy tradeoff to achieve wing borne flight within a few seconds of leaving the ship deck.
The piloting technique is complex to execute if done manually and the takeoff maneuver is very harsh and highly disorienting to the pilot as very high pitch rates, normal accelerations and pitch attitudes are generated on exiting the ramp. Hence for the LCA Naval variant the CLAW team has automated this phase of flight for handsfree takeoff by the pilot who is only required to guide the aircraft to follow the centre line by steering the nosewheel using the rudder pedals.
Full control is handed to the pilot only after wing borne flight is achieved thereby significantly reducing the pilot workload and reducing the training required for safe takeoff from the ship deck ramp.
Several successful shore based ramp takeoffs have been performed at Goa both under day and night conditions validating the automated ramp based takeoff mode and the initial pilot responses have been very promising.
Question 8: You were the Former Director of CSIR-NAL and have over 40 years of experience in the field of Aircraft Flight Mechanics & Control. Tell us how did you decide to enter the Aviation Industry in India when it was in nascent stages?
My entry into the aeronautical field was purely accidental. If I look back now over the past 40 years of my personal and professional life and some of the disjointed events , I think I was truly fated to join and serve NAL and destined to work on the LCA programme.
I obtained my Bachelors degree in Electronics and Communication Engineering from NIT Tiruchirapalli in 1976, my masters in Instrumentaion and control engineering in 1978 from IIT Kharagpur and then joined NAL in Oct. 1978 after a brief stint at CMTI Bangalore.
I consider myself singularly fortunate as I have always had ideal parents, loving family, qualified teachers, dedicated professors and understanding bosses who have not only encouraged and supported me at every stage of my professional career and personal life but also gave me total freedom to do my work.
I was selected for the German DAAD fellowship in 1985 and deputed to the DLR Institute of flight research in Braunschweig who were then tasked with the development of a new transport aircraft inflight simulator ATTAS based on a VFW 614 platform. This was primarily started to be used for simulation of the FBW flight control laws for the Airbus-320 aircraft – a global and industry first. This was my first practical experience with actual flight hardware and systems. I was again lucky and fortunate to be associated with the design team for the development of the model following flight control laws of ATTAS inflight simulator from day 1 I joined the Institute .
I learnt a lot during the 4 years I was associated with this project in Germany and this practical experience gave me the necessary exposure, confidence and came in very handy when the LCA CLAW team was formed and I was asked to be the technical lead in the control law team for developing the longitudinal axis control laws which included several inflight simulation campaigns.I have been in this exciting field for over 40 years and have absolutely no regrets for having chosen NAL and this niche subject for my career. I was initially reluctant to takeover as Director, NAL in 2011 but then I realized that this would be an excellent way to pay back to the wonderful organisation which had moulded my career and given me so much job satisfaction and happiness in life.