Heinkel HD 37

Infobox Aircraft
name=HD 37, I-7


caption=
type=Fighter
national origin=Germany
manufacturer=Heinkel, TsKB
designer=
first flight=avyear|1928
introduced=
retired=
status=
primary user=Soviet Air Force
more users=
produced=
number built=around 134
variants with their own articles=The Heinkel HD 37 was a fighter aircraft designed in Germany in the late 1920s, but produced in the USSR for Soviet Air Force service. It was a compact, single-bay biplane with staggered wings of unequal span braced by N-struts. The pilot sat in an open cockpit and the main units of the tailskid undercarriage were linked by a cross-axle.

Design and development

It had been designed for the clandestine air force that the Reichswehr was training at Lipetsk, but had been rejected by German officials, who purchased the Fokker D.XIII instead.

Fortuitously for Heinkel, the Soviet Air Force was experiencing something of a crisis at the time, faced with the obsolescence of its main fighter, the Polikarpov I-5 and with no replacement apparently forthcoming from domestic manufacturers. When Heinkel was approached to provide an alternative design, the firm was able to offer the HD 37, and the two prototypes were flown to Moscow in early 1928. Flight testing produced mixed results. While the basic design was apparently sound, Soviet test pilots reported many deficiencies in handling, and Heinkel was presented with a long list of complex changes to be made. Heinkel responded with the Heinkel HD 43, and when the same Soviet test pilots found that they liked it even less than the HD 37, attention shifted once again to the previous design by the end of 1929. Early the following year, the Soviet government bought a licence to manufacture the type for the next three years, paying Heinkel 150,000 Marks for it. Manufacturing was to be carried out by TsKB, and the designation I-7 was assigned.

Many of the fixes that had been adopted in the creation of the HD 43 were eventually implemented in the I-7 as well, along with other modifications, and by the time the first examples flew in summer 1931, flight test results were positive. Despite ongoing difficulties in obtaining materials, 131 examples were produced by 1934. Most of these served briefly with units in Belarus, but by the time the last examples were leaving the factory, the type was already obsolescent itself.

pecifications (I-7)

aerospecs
ref=
met or eng?= met

crew=One pilot
capacity=
length m=6.95
length ft=22
length in=10
span m=10.00
span ft=32
span in=10
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=3.20
height ft=10
height in=6
wing area sqm=25.9
wing area sqft=279
swept area sqm=
swept area sqft=
rot area sqm=
rot area sqft=
volume m3=
volume ft3=
aspect ratio=
empty weight kg=1,419
empty weight lb=3,121
gross weight kg=1,792
gross weight lb=3,942
lift kg=
lift lb=

eng1 number=1
eng1 type=Mikulin M-17F
eng1 kw= 540
eng1 hp= 730
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=291
max speed mph=182
max speed mach=
cruise speed kmh=
cruise speed mph=
range km=700
range miles=440
endurance h=
endurance min=
ceiling m=7,200
ceiling ft=23,600
glide ratio=
climb rate ms=9.7
climb rate ftmin=1,900
sink rate ms=
sink rate ftmin=

armament1=2 × fixed, forward-firing 7.62 mm PV-1 machine guns
armament2=
armament3=
armament4=
armament5=
armament6=

aircontent
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Notes

References

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