Militär-Apparat MA-7

Militär-Apparat MA-7
Role	Fighter aircraft
Manufacturer	K & W
Designer	August Häfeli
First flight	1925
Introduction	February 1926
Retired	April 1926
Primary user	Swiss Air Force
Number built	1

The Militär-Apparat MA-7, also known as the Häfeli MA-7 and K & W MA-7, was a prototype fighter designed by August Häfeli in Switzerland. It flew in two different engine configurations, neither of which were deemed satisfactory and so the type did not enter series production. However, it did achieve a Swiss record for flying at an altitude of 9,800 metres (32,200 feet) above sea level in 1926.

Design and development[]

Designed by August Häfeli in response to a Swiss Air Force requirement for an indigenous fighter design, the MA-7 was a biplane of fabric-covered wood construction with N-shaped wing struts like its predecessor the Fokker D.VI of 1918. Ailerons were installed only on the upper wing, which also contained an auxiliary gravity fuel tank. Power was provided by a 300 hp (220 kW) Hispano-Suiza 8Fb HS42 V-8 liquid-cooled engine manufactured in Switzerland under license. The aircraft was built by K & W in 1925 and handed over for trials in February 1926.^[1]^[2]

The prototype was returned to the manufacturer in April 1926 due to unsatisfactory flight characteristics and performance. K & W responded with the installation of an indigenous 400 hp (300 kW) engine. This, however, proved too large and heavy for the frame and entire MA-7 project was subsequently discontinued. The Swiss Air Force procured the French Dewoitine D.1 as their replacement fighter instead.^[1]

Records[]

On 23 April 1926, test pilot Max Cartier set a Swiss record of 9,800 metres (32,200 feet) above sea level with the MA-7.^[3]

Operators[]

Switzerland

Swiss Air Force

Specifications[]

Data from Urech & Hunziker, 1974^[2] Fader, 2013^[4]

General characteristics

Crew: One
Length: 6.61 m (21 ft 8 in)
Wingspan: 9.91 m (32 ft 6 in)
Height: 2.79 m (9 ft 2 in)
Wing area: 23.75 m² (255.6 sq ft)
Empty weight: 843 kg (1,858 lb)
Gross weight: 1,213 kg (2,674 lb)
Powerplant: 1 × Hispano-Suiza 8Fb HS-42 V8, liquid-cooled aircraft engine, 220 kW (300 hp)

Performance

Maximum speed: 235 km/h (146 mph, 127 kn)
Cruise speed: 255 km/h (158 mph, 138 kn) (econ cruise)
Range: 300 km (190 mi, 160 nmi)
Service ceiling: 7,600 m (24,900 ft)
Rate of climb: 9.2 m/s (1,810 ft/min)

References[]

^ Jump up to: ^a ^b Balous, Miroslav (2009). "K+W/Häfeli MA-7". Letectví a kosmonautika (in Czech). 85: 48.
^ Jump up to: ^a ^b Urech, Jakob; Hunziker, Emil (1974). Die Flugzeuge der Schweizerischen Fliegertruppe seit 1914 (in German). Hrsg. von der Abt. der Militärflugplätze Dübendorf, Verlag Th. Gut & Co, 1. Aufl. Stäfa. p. 134.
^ Dietschi, Von Willy (1960). "Oltner Flugpioere". Oltner Neujahrsblätter (in German). 18: 16. Retrieved 5 February 2020.
^ Fader, Michael E. (2013). "Häfeli Militär Apparat MA-7". wings-aviation.ch. Retrieved 5 February 2020.

[balous-1] Jump up to: ^a ^b Balous, Miroslav (2009). "K+W/Häfeli MA-7". Letectví a kosmonautika (in Czech). 85: 48.

[urich-2] Jump up to: ^a ^b Urech, Jakob; Hunziker, Emil (1974). Die Flugzeuge der Schweizerischen Fliegertruppe seit 1914 (in German). Hrsg. von der Abt. der Militärflugplätze Dübendorf, Verlag Th. Gut & Co, 1. Aufl. Stäfa. p. 134.

[dietschi-3] Dietschi, Von Willy (1960). "Oltner Flugpioere". Oltner Neujahrsblätter (in German). 18: 16. Retrieved 5 February 2020.

[4] Fader, Michael E. (2013). "Häfeli Militär Apparat MA-7". wings-aviation.ch. Retrieved 5 February 2020.

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