|The prototype Fieldmaster at the 1984 Farnborough airshow, 9 September 1984|
|National origin||United Kingdom|
|First flight||17 December 1981|
The NAC Fieldmaster was a British agricultural aircraft of the 1980s. A turboprop powered single-engined monoplane, it was built in small numbers and used both as a cropsprayer and a firefighting aircraft.
Development and design
NDN Aircraft, which was set up in 1976 by Desmond Norman, one of the founders of Britten-Norman, the manufacturers of the Islander, to build the Firecracker trainer, designed a new agricultural aircraft. The resulting aircraft, the NDN-6 Fieldmaster was a large single-engined low-winged monoplane with a fixed tricycle undercarriage, powered by a Pratt & Whitney Canada PT6 turboprop engine, the first western-built agricultural aircraft to be designed for turboprop power. Novel features included an integral hopper made of Titanium to carry its chemical payload, which was dispersed via spray nozzles built into the flaps under the aircraft's wings.
The first prototype flew on 17 December 1981 at NDN's airfield at Sandown, Isle of Wight. TNDN moved the premises to Cardiff, Wales in 1985, renaming itself the Norman Aeroplane Company (NAC). Production finally started in 1987. It was intended that parts would be produced by UTVA in Pančevo, Yugoslavia (now in Serbia) to be assembled in Cardiff.
NAC went into receivership in 1988, after the production of six Fieldmasters, including the prototype. Brooklands Aerospace attempted to continue production, rebuilding one of the Fieldmasters with a more powerful engine as a specialised firefighting aircraft as the Firemaster 65, but these attempts were stopped by the outbreak of civil war in Yugoslavia.
A final attempt at production was made by the Turkish Aeronautical Association (Türk Hava Kurumu - THK) who started licensed production in 1997. This ended in 1999 after completion of two complete aircraft and a further two airframes lacking engines.
- NDN-6 Fieldmaster
- The initial designation for the prototype; one built.
- NAC Fieldmaster
- Designation of production aircraft after the formation opf the Norman Aeroplane Company (NAC); five built.
- Brooklands Aerospace Firemaster 65
- A rebuilt Fieldmaster with more powerful engine and firefighting equipment; one conversion.
- THK Fieldmaster
- Production in Tukey by Türk Hava Kurumu (THK); four built
Specifications (NAC 6)
Data from Jane's All the World's Aircraft 1988-89 
- Crew: one
- Capacity: one passenger or 2,032 kg (4,480 lb) dry chemicals or 2,366 litres (625 US Gallons) liquid
- Length: 11.02 m (36 ft 2 in)
- Wingspan: 16.23 m (53 ft 3 in)
- Height: 4.12 m (13 ft 6 in)
- Wing area: 33.25 m² (358 ft²)
- Airfoil: NACA 23012
- Empty weight: 2,266 kg (4,995 lb)
- Max. takeoff weight: 4,535 kg (10,000 lb)
- Powerplant: 1 × Pratt & Whitney Canada PT6A-34AG turboprop, 559 kW (750 shp)
- Never exceed speed: 318 km/h (172 knots, 198 mph)
- Maximum speed: 265 km/h (143 knots, 165 mph) at sea level
- Cruise speed: km/h (knots, mph)
- Stall speed: 111 km/h (60 knots, 69 mph)
- Range: 1,853 km (1,000 nm, 1,150 mi)
- Service ceiling: 5,547 m (18,200 ft)
- Rate of climb: 4.88 m/s (960 ft/min)
- Wing loading: kg/m² (lb/ft²)
- Power/mass: W/kg (hp/lb)
- Aircraft of comparable role, configuration and era
- Barnett 1980, p.800.
- Barnett 1981, p.649-652.
- Taylor 1988, p.299.
- Flight International, 19 March 1988, p.12
- Flight International 6 August 1988, p.11.
- Flight International 6–12 December 1989
- Donald 1997, p.673.
- Deniz, Tuncay. "THK" Turkish Aircraft Production. Retrieved 5 September 2008.
- Taylor 1988, pp.299-300.
- "Fieldmaster fighter proves its worth". Flight International, 31 October 1987, p. 15.
- "Jugoslavs will build Fieldmaster". Flight International, 19 March 1988, p. 12.
- "Uprated Fieldmaster makes first flight". Flight International, 6–12 December 1989, p. 21.
- "Norman calls in receiver". Flight International, 6 August 1988, p. 11.
- Barnett, Cliff. "Enter the Fieldmaster". Flight International, 30 August 1980, p. 800.
- Barnett, Cliff. "NDN Fieldmaster". Flight International, 29 August 1981, pp649–652.
- Blech, Robin. "Norman's mighty Fieldmaster". Flight International, 6 February 1988, pp. 22–26.
- Donald, David. (editor). The Encyclopedia of World Aircraft Leicester:Blitz, 1997. ISBN 185605375X.
- Taylor, J.W.R.(editor) Jane's All the World's Aircraft 1988-1989. Coulsdon, Surrey, UK: Jane's Information Group, 1988. ISBN 0-7106-0867-5.
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