By Anantha Krishnan M
Express News Service
Bangalore: India's self-reliance capabilities in taking up naval aircraft projects in future is sure to get a fillip with the Aeronautical Development Agency (ADA) and Hindustan Aeronautics Limited (HAL) beginning the 'countdown of sort' for the first flight of Light Combat Aircraft (LCA) Naval Prototype (NP-1). The inspiring bit of this project is probably the maturing of a military industrial complex and the technological leap of Indian defence units – both government-owned and private sector.
The unique requirement of naval aircraft is the complex amalgamation of saline and humid environment of operation, restricted availability of deck run for launch or recovery and high operating load conditions. Such intricate needs call for basic design change to suit the carrier operations leading to strengthening of aircraft structure and landing gear, inclusion of leading edge vortex control (LEVCON) and arrester hook, improved engine, enhanced aerodynamic performance and incorporation of special material.
The LEVCON surface is fitted at the front tip of the aircraft wing to ensure low landing speed, good controllability and better vision for the pilot. Such a surface is used on state-of-the-art US marine aircraft F-18. Usually, in leading and trailing edges linear actuators are used, however, the LEVCON was a biggest challenge to the designer as it has to be operated by a concealed rotary actuator with aerodynamic profiling of the connecting surface. The rotary actuator was designed in collaboration with foreign vendor.
“It threw related challenging requirement of testing and certification at a safety factor of 150 percent of maximum working load. The LEVCON test rig was designed in-house along with a dummy test specimen rotary actuator with similar specifications to avoid loss of usable item, thus saving few crores of rupees to the exchequer,” sources told Express.
The feature of launch and recovery onboard carrier was another herculean assignment to be managed. The flare-less landing with high sink rate of 7.1 m/sec and heavy thumping with engine to full throttle till arrested by deck cable, is akin to a controlled crash of the aircraft on the ship every time it operates. This yields five times of loading on main landing gear as compared to Tejas. Sources say that in horizontal direction, the arrested shock recovery produces axial loads on aircraft structure of the tune of 4.5 g, calling for re-certification of all line replacement units (LRUs), components and associated systems of naval version to ensure fail safe operation repeatedly.
“The ramp takeoff switch ensures that the aircraft is prepared with pre-defined functionality of each system in ship-borne operational mode. This ensures safe launch at max capable all-up weight with full fuel and weapon stores from a ship ski jump of 14 deg ramp profile, when released from deck hydraulic stopper. Such a dramatic launch imposes harsh loading of nose-landing gear during take-off ski-jump run amounting to five times of the IAF Tejas values. All of a sudden the landing gear is un-loaded at the point of exit of the ramp and allowed to extend to its fullest stroke in a wink of a second,” say sources.
The take-off and landing logics are integrated in its quadruplex digital redundant flight control system and open architecture computer for efficient interface between the pilot and the aircraft with the aim of easing work-load during launch and recovery phase and fail safe operation.
The LCA Navy is designed for strict operating conditions and emergency recovery, in that it can bring back weight to landing limits, quickly by jettisoning 1000 kg fuel in three minutes with the help of specially-designed fuel dump system. The testing and certification of unique design features for LCA Navy called for systematic plan of action to create new test facilities and deep study of certification philosophy.
The ADA has designed and fabricated various types of simulators, including engineer-in-loop, real-time software development and maintenance. The shore-based test facility (SBTF) at Goa with ski-jump launch and arrested recovery similar to aircraft carrier is ready. The arrester hook test facility, LEVCON test rig and landing gear drop test rig are also developed in-house.
There are more than 100 agencies involved with the LCA-Navy project. They include DRDO, HAL, CSIR, PSUs, private sector and academia, spread all over India, ranging from NAL, CARE, DARE, CVRDE, , DEBEL, LRDE, Midhani, CSIO, TCS, IITs, IISc and Naval Aviation at NHQ.
Copyright@The New Indian Express.
BLOGGER'S NOTE: A trimmed version of the above report appeared in today’s Express. Additional inputs are added to the above report on the blog for the benefit of Tarmak007’s registered members, regular visitors, guests and ‘advisors.’ Please note that these information are collated from different sources in ADA, HAL, Navy and DRDO and stitched together in layman’s language. While I can vouch for the authenticity of inputs, you may please buzz me if I go wrong. It is tough to penetrate at times, especially to pocket photos from multiple sources. The watermarks on the photos are just reminders that these are not supplied to the blogger through some 'annual contract', but sourced by the blogger after constant-chase and follow-ups. Tarmak007 salutes all sources & friends in DRDO, Navy, IAF, HAL and ADA, who often go out of their way to fetch authentic information on LCA. It has been a huge learning process for Tarmak007 every time a new project/technology is taken on the write path. I am delighted that all of you are also part of this inspiring journey!