India's first indigenously designed and developed civilian aircraft
Operating Procedure ground runs yet to be completedWeight problem of PT2 being tackled
Bangalore: The second prototype (PT2) of India's first indigenously designed and developed civilian aircraft Saras is on the verge of making its maiden flight this week. Designed and built by the Bangalore headquartered National Aerospace Laboratories (NAL), a constituent of the Council of Scientific and Industrial Research, the eight to 14-seater Light Transport Aircraft Saras will follow in the footsteps of prototype one (PT1) which flew in May 2004.
While NAL have long completed the PT2's low speed taxi trials (where the aircraft is taxied to a speed of up to 60 knots) and high speed taxi trials (where the aircraft is pushed between 60 and 90 knots and the nose wheel just lifts off the ground), the three Standard Operating Procedure (SOP) ground runs a statutory requirement under the Directorate-General of Civil Aviation (DGCA) are yet to be completed.
During the SOP ground runs the aircraft will be checked for safety related snags while it is identically configured to the parameters (such as the weight of aircraft, centre of gravity, amount of fuel) that will be present during its first flight. While two SOP ground runs have been successfully competed, the third is due any day now.
The aircraft's maiden flight with pilots from the Aircraft and Systems Testing Establishment at the controls will then follow.
Envisaged to play multiple roles, including that of a feeder line aircraft, air taxi, ambulance, executive aircraft, aerial survey and reconnaissance, PT1 had suffered from serious weight problems. Against an empty aircraft design value of 4,125 kg, it weighed 5,118 kg, a near 25 per cent increase, affecting its range, fuel carrying capacity, fuel economy, and its design payload capacity of 1,232 kg.
Though PT2 has not particularly addressed the knotty weight issue, it will nevertheless have a higher powered (1,200 pounds) Pratt and Whitney pusher, turboprop (rear facing propellers) configured engines (PT6-67A), new propellers and a brand new subwing that supports the engine to the fuselage.
Commenting on the weight issue, the Head of NAL's Centre for Civil Aircraft Design and Development, K. Yegnanarayan, said that it was not possible to reduce the weight of PT2 since the various parts for the two prototypes had been made together.
However, Dr. Yegnanarayan said that a `weight optimisation' exercise had already been put in place and that the weight would be brought down by around 500 kg in the production standard, or limited series production aircraft. "With parts of the production aircraft especially the wing and tail plane to be made using carbon fibre composites a reduction will not be too difficult."
With this in mind NAL have embarked on a programme to make three composite airframes, which will form the backbone of a lighter Saras.
According to Dr. Yegnanarayan, while one of the airframes will be used for flying, the other two will be used for structural and fatigue testing.
Saras, named after the Indian crane known for its grace and beauty in flight, marks a cornerstone in the Indian aviation industry's quest to design and develop the first commercial civilian aircraft. NAL are hoping for formal DGCA clearance for the Saras by 2009.