The Transavia PL-12 Airtruk is a single-engine agricultural aircraft designed and built by the Transavia Corporation in Australia. The Airtruk is a shoulder-wing strut braced sesquiplane of all-metal construction, with the cockpit mounted above a tractor-location opposed-cylinder air-cooled engine and short pod fuselage with rear door. The engine cowling, rear fuselage and top decking are of fibreglass. It has a tricycle undercarriage, the main units of which are carried on the lower sesquiplane wings. It has twin tail booms with two unconnected tails. Its first flight was on 22 April 1965, and was certified on 10 February 1966.[2]
Head on view showing the PL12s deep fuselage and twin fins on trailing booms
It was developed from the Bennett Airtruck designed in New Zealand by Luigi Pellarini. It has a 1 tonne capacity hopper and is able to ferry two passengers as a topdresser. Other versions can be used as cargo, ambulance or aerial survey aircraft, and carry one passenger in the top deck and four in the lower deck.
The Airtruk is also sometimes known as the Airtruck. Because the name "Airtruck" was registered by the New Zealand companies Bennett Aviation Ltd and Waitomo Aircraft Ltd, for their PL-11, Transavia found another name for their PL-12 ("Airtruk").
July 1978 saw the first flight of an improved model, the T-300 Skyfarmer, which was powered by a Textron Lycoming IO-540-engine. This was followed in 1981 by the T-300A with improved aerodynamics.[2] Transavia ceased production of the T-300 in 1985.
In 1982, certification was undertaken to enable sales in the North American market. Assistance was provided by the Aeronautical Research Laboratories (ARL) of the Defence Science and Technology Organisation (DSTO) and extensive tests carried out on the ground and in subsequent flight flutter clearance trials. ref. DSTO Structures Tech. Memo. 341
In 1985, an extended version was produced and released as the T-400. The engine was changed from a 6-cylinder to an 8-cylinder and the tail booms extended by 750 millimetres (30 in). Other minor changes were made to the aerodynamics. Flutter clearance tests were again carried out by ARL and manufacture proceeded.[3]
An isolated flutter incident was reported in 1986 involving violent oscillations of the rudder and tail boom on the T-400 during a delivery flight. Investigations were carried out by ARL, and a split mass balance arm was fitted to each rudder. Prior to this, the aircraft had relied on frictional damping provided by the lengthy control cables. The modified aircraft was tested both on the ground and in flight trials in March 1988 over Port Philip, near Melbourne, Australia. All attempts to induce the oscillations showed that there was no indication of a mode of vibration becoming unstable. The maximum speed achieved was 160 knots (180 mph; 300 km/h) in a steep dive. Oscillations were induced with an air operated tool fitted with an out-of-balance rotating mass. This device had a rotational speed from 18 Hz down to zero for each charge of the compressed air cylinder.[4]
Empty weight: 1,709 lb (775 kg) :: PL-12U 1,830 lb (830 kg)
Max takeoff weight: 4,090 lb (1,855 kg) (agricultural mission)
Fuel capacity: 181.5 L (47.9 US gal; 39.9 imp gal) in two upper wing fuel tanks with optional second tank in each wing for a total of 373 L (99 US gal; 82 imp gal)
^Goldman, A.; Galea, S. (1985). Flutter clearance tests on a Transavia PL-12/T-400 Skyfarmer. Melbourne: Aeronautical Research Laboratories. ISBN9780642097453.
^Taylor, John W.R., ed. (1975). Jane's all the world's aircraft, 1975-76 (66th annual ed.). New York: Franklin Watts Inc. pp. 9–10. ISBN978-0531032503.
Bibliography
Donald, David (editor). The Encyclopedia of World Aircraft. Leicester, UK: Blitz, 1997. ISBN1-85605-375-X.
Taylor, John W R. (editor). Jane's All the Worlds Aircraft 1976-77. London:Jane's Yearbooks, 1976. ISBN0-354-00538-3.
Taylor, John W R. (editor). Jane's All the Worlds Aircraft 1988-89. Coulsdon, Surrey, UK: Jane's Information Group, 1988. ISBN0-7106-0867-5.
