New Aircraft From Old

Press, Volume CIV, Issue 30937, 18 December 1965, Page 10

New Aircraft From Old

fßv J. r.f TOURING 1965 the Austoaton end New Zeeland agricultural aviation industry has been able to select new aircraft from the many and varied American agricultural aircraft and also from the newly-developed Australian and New Zealand agricultural aircraft. Obviously, aircraft buUt specifically for the conditions most likely to be encountered locally are of more value than those mass produced for a world-wide range of duties and localities. Until recently Australia and New Zealand had very Utile

in the way of RMNf* developed agricultural Orcraft. But in both toe utiMtary and civil spheral more and more aircraft an being displaced as new aircraft appear on the market. Then surplus .aircraft are moatiy training and transport aircraft such as Harvards, Wtaraways. and in small numbera DC-3's. They are being purchased mainly with a view to modification for solely agricultural purposes. To develop an aircraft of a speciaiieed nature to production line atatus is extremely costly and time consuming, whereas these aircraft of proven quality are leas costly and are more readily obtained. The modifications include strengthening of the airframe, the addition of a hopper, a reliable engine, and the adoption of built-in safety features. To date there have been two conversions of this type in New Zealand. They are, the Bennett Aviation Airtruck from ex-R.N.Z.A.F. North American Harvards, and the other is a creation of a heavyweight aerial topdresser from DC-3 airliners. Australian efforts in this field have been the Yeoman Oropmaster and the C.A.C. Ceres, both multipurpose agricultural aircraft developed from the CA.C. Wirraway (an Australian version of the Harvard) which ia ex-RA.A.F. A further addition is the SA-29 Spraymaster derived from the DHC-1 Canada Chipmunk basic trainer. This aircraft has been in wide use throughout the world. The Spray master has just recently been put on the market in Australia and New Zealand. An all-metal low-wing single-engined agricultural aircraft, the Spraymaster is manufactured by Aerostructures of Bankstown airport, Sydney. The low-wing and location of the 50-gallon hopper on

the centre of gravity are two favoured features of a sprayinc aircraft. Tbe engine is an M>atiM Continental with an option of metal or wooden propellerA salient feature of modern agricultural aircraft is pilot and aircraft safety and in the Spraymaster the pilot has an energy absorption seat and a safety harness produced to stand a 28G strain located within the roll-over truss protected cockpit Tbe aircraft also has a low stalling speed, stable flight characteristics and offers good visibility. Wire cutters on the undercarriage legs and in front of the windscreen will sever average gauge wires and a wire deflection cable from tbe top of tbe canopy to tbe top of the tail will deflect high tension wires without losing the tall unit

A large •‘undercarriage" track and wheel base reduces chances of ground looping, crabbing or nosing over during landing, taxi-tag and takeoff. The airframe has also been “beefed up” to endure tbe rigours of sustained structural stresses with the minimum amount of maintenance in the field. The spray booms are located in the trailing edge of the mainplane and cover the full wing span providing a swath of high or low density according to the number of nozzles used—24 to 52. The spray is distributed through the booms’ on the trailing edge to use the downwash of the wing to give good penetration. The spray is pumped from the hopper to the spray booms by a wind driven pump located directly beneath the fuselage. The Spraymaster is capable of operating with its loaded weight of 23001 b from a plat-eau-type airstrip 700 feet long as it has a landing roll of 400 feet and a take-off run of 650 feet The basic price of the Spraymaster in Australia is £4OOO