Marinens Flyvebaatfabrikk M.F.10

M.F.10
M.F.10 F.204.
Role	Military trainer seaplane
National origin	Norway
Manufacturer	Marinens Flyvebaatfabrikk
Designer	Johann E. Høver
First flight	7 July 1929
Retired	10 April 1940
Primary user	Royal Norwegian Navy Air Service
Number built	4

The Marinens Flyvebaatfabrikk M.F.10 (also known as the Høver M.F.10, after its designer) was a military trainer seaplane built in Norway in 1929.

It was a largely conventional biplane design derived from the M.F.9 fighter, and sharing its single-bay wings with additional struts bracing the lower wings to the fuselage sides. It differed from its predecessor in having two a second open cockpit in tandem with the pilot's, and while the prototype shared the M.F.9's wooden construction and Vee-engine, later examples had a tubular structure and a radial engine. Intended for advanced training, the aircraft was built strongly enough to allow for aerobatics and dive bombing. Having been built by the specifications from a US light dive bomber, the M.F.10 could both dive and fly on its back.

Marinens Flyvebaatfabrikk began construction of a new trainer to replace the Hansa-Brandenburg W.33 in this role. The prototype, F.4 (V), first flew on 7 July 1929 and underwent stringent testing before moving on to the production stage. F.4 first flew with a 160 horsepower (120 kW) Mercedes engine with a top speed of 157 km/h and a climbing speed of 2,000 meters in 25 minutes. The Mercedes power plant was replaced with a Hispano Suiza model with a top speed of 185 km/h and an ability to climb 2,000 metres in less than eight minutes.

From May 1930 the prototype was given the registration number F.200, in line with the new number series to be used for two-seat trainers. The Royal Norwegian Navy Air Service's (RNNAS) goal for the type was to have one aircraft based at each of the three Norwegian naval air stations, leading to the delivery of two new aircraft, one in 1932 and another in 1933. The two new-built aircraft were delivered with Armstrong Siddeley Cheetah engines and a steel tube hull instead of F.200's wooden hull. Designated as M.F.10Bs and numbered F.202 and F.204, the two aircraft were modified with a new type balance rudder which greatly improved their flying characteristics. When F.202 was written off after a May 1935 crash a replacement aircraft was built and delivered in March 1936 as the fourth and last of the type. The same year F.200 had its wooden hull replaced with a steel tube one. In addition to its training role the M.F.10 was also used for operational tests, such as seaplanes' ability to land on and take off from snow and ice on frozen lakes. Successful tests were carried out in March 1933 with F.202 both on Borresvannet lake and on the snow-covered Kjeller air station.

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