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The Yackey Monoplane was an American three seat parasol monoplane flown in the late 1920s. Two prototypes had some success in the 1927 New York - Spokane National Air Derby and orders were placed but a crash killed its designer and ended production.

Yackey Monoplane
Role	Light three seat passenger or mail carrier Type of aircraft
National origin	United States
Manufacturer	Yackey Aircraft Company
Designer	Wilfred Yackey
First flight	1927
Number built	2

Design and development

The Yackey monoplane had a parasol wing built around two spruce box spars with plywood skinning ahead of the forward spar. It used the popular Clark Y airfoil and had a constant chord with blunt tips. It was braced to the fuselage on pairs of parallel struts to the lower fuselage longerons, and a central, short inverted vee cabane to the top of the fuselage.[1]

It was powered by a 225 hp (168 kW) Wright Whirlwind J-5 9-cylinder radial mounted in the nose with its cylinders exposed for cooling. The fuselage was flat-sided apart from raised upper decking.[1] Both the cockpits were open, with the two passengers[2] placed side-by-side over the wing with entry via full-depth doors. The pilot sat just aft of the wing trailing edge, where a cut-out provided a wider upper field of view. Baggage or mail was placed in a large hold behind the pilot. Its fuselage tapered rearwards to a cropped-triangular fin with a comma profile, balanced rudder. The tailplane was semi-elliptical in plan and mounted on top of the fuselage, each side braced from below with a strut and a parallel wire and from above with a wire to the fin. Elevators were full and rounded, with a large gap between them for rudder movement.[1]

The Yaxley had fixed, conventional landing gear with large wheels, each fitted with brakes and on half-axles mounted on the lower fuselage longerons. Short, vertical legs were mounted on the forward wing struts which were reinforced at those points by diagonal struts to the wing centre-section. Drag struts sloped upwards to the root of the rear wing strut. Its spring-steel tailskid was steerable.[1]

Operational history

The two prototypes took part in the 1927 National Air Derby, a 24 hour race between New York and Spokane.[1] One, piloted by Hamilton Lee, gained fifth place and a $500 prize.[3]

By October 1927 Yackey had rebuilt and reorganized his two factories for serial production at an initial rate of one in three weeks, moving to one a week at the start of 1928. They had firm orders for five.[1] However, these plans were abandoned after 4 October when Yackey died making a final test flight of a Monoplane before handing it over to its new owner. A newly reinforced wing bracing failed during the programme of aerobatics he routinely used in a final, personal test of all his aircraft.[4][5]

Specifications

Data from Aero Digest 1927,[1][6]

General characteristics

• Crew: One
• Capacity: Two passengers
• Length: 26 ft 2 in (7.98 m)
• Wingspan: 41 ft 2 in (12.55 m)
• Height: 8 ft 4 in (2.54 m)
• Wing area: 284 sq ft (26.4 m²)
• Airfoil: Clark Y
• Empty weight: 1,460 lb (662 kg) 2460
• Fuel capacity: 84 US gal (70 imp gal; 320 l)
• Payload: 1,000 lb (450 kg)
• Powerplant: 1 × Wright J-5 Whirlwind 9-cylinder air-cooled radial piston engine, 225 hp (168 kW)
• Propellers: 2-bladed Standard Steel

Performance

• Maximum speed: 140 mph (230 km/h, 120 kn)
• Cruise speed: 115 mph (185 km/h, 100 kn) at 1,600 rpm
• Stall speed: 40 mph (64 km/h, 35 kn)
• Landing speed: 40 mph (64 km/h; 35 kn)

References

Bibliography

• Horsefall, J.E., ed. (October 1927). "The Yackey Monoplane". Aero Digest. New York City: Aeronautical Digest Publishing Corp. p. 420.
• Horsefall, J.E., ed. (September 1927). "1927 National Derby and Air Race results". Aero Digest. New York City: Aeronautical Digest Publishing Corp. p. 382.

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