Koolhoven F.K.55

The Koolhoven F.K.55 was a Dutch fighter prototype of the 1930s. Designed as a high-performance aircraft, it never made it past the prototype stage.

Development

Design on a Koolhoven high-performance aircraft first started late in 1937. The result, finished in early 1938 was the F.K.55, a single-seat fighter of radical design with contra-rotating propellers and an engine housed behind the pilot. It had initially been proposed to do away with ailerons on the wings, and replace them with "slot-spoilers" for lateral control, however this idea was abandoned early in the project.

Of mixed metal and wood construction with wooden wings, the F.K.55's front fuselage was made of steel tube while wood formed the tail and rear fuselage. Its Lorraine Pétrel engine afforded just enough energy to take off and to stay in flight, and many designers thought that it should be upgraded to a supercharged Lorraine Sterna engine which would have afforded greater performance, however this never happened.

Operational history

The aircraft flew for the first time in June 1938. It flew for two minutes then landed. Its performance and lack of ability to stay in the air due to its weak engine resulted in the project being cancelled in the same year.

pecifications

aerospecs
ref= [Green & Swanborough, pg 323]
met or eng?=met

crew=1
capacity=
length m=9.25
length ft=30
length in=4
span m=9.60
span ft=31
span in=6
swept m=
swept ft=
swept in=
rot number=
rot dia m=
rot dia ft=
rot dia in=
dia m=
dia ft=
dia in=
width m=
width ft=
width in=
height m=2.60
height ft=8
height in=6
wing area sqm=16.00
wing area sqft=172.23
swept area sqm=
swept area sqft=
rot area sqm=
rot area sqft=
volume m3=
volume ft3=
aspect ratio=
wing profile=
empty weight kg=1600
empty weight lb=3527
gross weight kg=2208
gross weight lb=5026
lift kg=
lift lb=

eng1 number=1
eng1 type=Lorraine Pétrel 12Hrs 12-cylinder Vee
eng1 kw= 640
eng1 hp= 860
eng1 kn=
eng1 lbf=
eng1 kn-ab=
eng1 lbf-ab=
eng2 number=
eng2 type=
eng2 kw=
eng2 hp=
eng2 kn=
eng2 lbf=
eng2 kn-ab=
eng2 lbf-ab=

max speed kmh=510
max speed mph=317
max speed mach=
cruise speed kmh=450
cruise speed mph=280
stall speed kmh=
stall speed mph=
range km=850
range miles=528
endurance h=
endurance min=
ceiling m=
ceiling ft=
g limits=
roll rate=
glide ratio=
climb rate ms=13.1
climb rate ftmin=2580
sink rate ms=
sink rate ftmin=

armament1=1 x 20 mm cannon firing through the propellor
armament2=4 x wing-mounted .303 machine guns
armament3=
armament4=
armament5=
armament6=

References

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