Engineering:PAC Fletcher

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Fletcher FU-24
PAC Fletcher Fu24 Aerial Topdresser.JPG
Fletcher FU-24 in Wanganui Aero Work (now Ravensdown) colours
Role agricultural aircraft
Manufacturer Fletcher Aviation
Designer John Thorp
First flight 14 June 1954
Introduction 1954
Status Production ceased, in active service
Number built 297
Variants PAC Cresco

The Fletcher FU-24 is an agricultural aircraft made in New Zealand. One of the first aircraft designed for aerial topdressing, the Fletcher has also been used for other aerial applications as a utility aircraft, and for sky diving.

Design and development

The FU-24 was loosely based on the Fletcher FD-25 Defender, designed by US aeronautical engineer and light aircraft enthusiast John W. Thorp, and originally conceived in 1951 as an STOL light attack aircraft. The prototype Defender was built by Fletcher Aviation in California and first flew in 1953. A few Defenders were later built in Japan .

At the time New Zealand top dressing operators were in the U.S. seeking a replacement for war surplus De Havilland Tiger Moths which formed the backbone of the industry. Thorp and Wendell Fletcher incorporated many elements of the Defender into a new design, the FU-24. A group of New Zealand top dressing operators gathered a hundred options for the design off the drawing board, and founded a company, Air Parts, to assemble the type in New Zealand, while a New Zealand farming company, Cable Price Corporation, funded the construction of two prototypes in the U.S. with the New Zealand Meat Producers Board acting as financial guarantor.

The first prototype FU-24 flew on 14 June 1954 in the United States , then was disassembled for shipment to New Zealand, together with the (unflown) second prototype. The original prototype had a 225 hp (168 kW) engine and open cockpit. Prior to production commencing, this design was altered to add an enclosed cockpit and more powerful 260 to 310 hp (230 kW) Continental engines.

The next 70 aircraft were delivered to New Zealand in kit form and assembled at Hamilton airport. From 1961 full production was undertaken locally, by Air Parts, which later became part of AESL and detail improvements and the option of dual controls were added, becoming the Mark II.

The Fletcher is a conventional low-wing monoplane with tricycle undercarriage, side-by-side seating in front of the wing and hopper and pronounced dihedral on the outer wing panels. A door aft of the wing's trailing edge on the port side allows access to a cargo compartment. The Fletcher's airframe is constructed entirely of aluminium, heavily treated to prevent corrosion.

Fletcher FU-24-950M of Fieldair at Thames airfield New Zealand in 1992

After the 257th aircraft the engine was changed to a 400 hp (300 kW) Lycoming IO-720 horizontally-opposed eight-cylinder engine (over a hundred earlier aircraft were re-built and re-engined by the factory). Some Fletchers have also flown with V-8 truck engines. In 1967 a PT6 turboprop version was built by James Aviation as ZK-CTZ, a 530 hp (400 kW) Garrett TPE 331-powered version followed in 1968 and a 665 hp (496 kW) Garrett-powered version in 1971, both for Robertson Air Service. Several others were converted aftermarket with these or Walter turbines, (including the first prototype, which flew until recently with a Walter). Two aircraft were also converted to Garrett TPE 331-10 engines by the Scone (NSW Australia) operator Airpasture. These aircraft have since flown many thousands of hours without incident.

In the mid 1970s, Pacific Aerospace decided the Fletcher design was reaching the limits of redevelopment and introduced the larger and stronger PAC Cresco. Despite the similar appearance this is a new aircraft, though sharing a few components. For several years production of the two continued side by side, but the type is now effectively out of production, (new Fletchers remain nominally available from the manufacturer, but no new aircraft have been built since a batch of five for Syria was completed in 1992).

Although Fletcher was the name of the manufacturer in the U.S. and the aircraft was called the FU-24, over time the type has become colloquially known as the Fletcher. Fletchers have been sold to most parts of the world, although they are rare in Europe and the US. Government orders came from many developing countries including Thailand, Syria, Iraq and Sudan.

Variants

  • FU-24 : Single-seat agricultural top dressing aircraft.
  • FU-24A Utility : Six-seat utility transport aircraft. One prototype built in the United States .
  • FU-24-950 : Two-seat agricultural top dressing aircraft. Also known as the Task Master in the United States.
  • FU-24-954 : Improved version.
  • Pegasus 1 : Military version developed by Frontier Aerospace, of Long Beach, California.

Operators

 Australia
  • Air Culture Pty
  • Pays Air Service
  • Superair
 New Zealand
  • Wareham Air Spray
  • Barr Brothers
  • Fieldair
  • James Aviation - peak of 36 aircraft
  • Mount Cook Airline - six aircraft
  • Ravensdown Aerowork (previously Wanganui Aero Work) - now three, peak of 12 aircraft
  • Robertson Air Service
  • Super Air
 Pakistan
  • Lahore flying club

Specifications (FU-24-954)

Data from Jane's All The World's Aircraft 1993–94 [1]

General characteristics

  • Crew: two
  • Capacity:
    • Six passengers or
    • 320 US gal (1,200 L) liquid or 2,350 lb (1,070 kg) powder hopper
  • Length: 31 ft 10 in (9.70 m)
  • Wingspan: 42 ft 0 in (12.80 m)
  • Height: 9 ft 4 in (2.84 m)
  • Wing area: 294.0 sq ft (27.31 m2)
  • Airfoil: NACA 4415
  • Empty weight: 2,620 lb (1,188 kg)
  • Gross weight: 4,860 lb (2,204 kg) normal maximum
  • Max takeoff weight: 5,430 lb (2,463 kg) agricultural
  • Fuel capacity: 67 US Gallons, 254 L (normal)
  • Powerplant: 1 × Textron Lycoming IO-720-A1A air-cooled flat-eight engine, 400 hp (300 kW)

Performance

  • Maximum speed: 145 mph (233 km/h, 126 kn) at sea level
  • Cruise speed: 130 mph (210 km/h, 110 kn) 75% power
  • Stall speed: 57 mph (92 km/h, 50 kn) flaps down
  • Never exceed speed: 165 mph (266 km/h, 143 kn)
  • Range: 441 mi (710 km, 383 nmi)
  • Service ceiling: 16,000 ft (4,900 m)
  • Rate of climb: 805 ft/min (4.09 m/s)

See also

Related development

Aircraft of comparable role, configuration and era

Notes

  1. Lambert 1993, p. 221.

References

  • Alexander, G. & J. S. Tullett, The Super Men. A.H. & A.W. Reed, Wellington, 1967
  • Ewing, Ross and MacPherson, Ross. The History of New Zealand Aviation, Heinemann, 1986
  • Geelen, Janic. The Topdressers NZ Aviation Press. Te Awamutu, 1983
  • Knowles, Alan. New Zealand Aircraft, IPL Books, Wellington, 1990
  • Lambert, Mark. Jane's All The World's Aircraft 1993–94. Coulsdon, UK:Jane's Data Division, 1993. ISBN:0-7106-1066-1.
  • Taylor, John W. R. Jane's All The World's Aircraft 1965–66. London:Sampson Low, Marston & Company, 1965.
  • Wood, Dereck, Janes World Aircraft Recognition Handbook, Jane's Publishing Company, London, 1982

External links