Type Single seat fighter Polikarpov I-7  Single seat fighter
Engine 1 BMW VI 7,3 Z 1 Mikulin M-17F
Dimensions Length 7,0 m , height 3,2 m ,  span  10,0 m, wing area  26,71 m2 , Length  6,95 m, height 3,20 m ,  span 10,0 m , wing area  26,7  m2 ,
Weights Empty 1267 kg, loaded 1685 kg , max. take off weight   Empty 1296 kg, loaded  1729 kg, max. take off weight   fuel and oil 200 kg
Performance Max.. speed  312 km/h at sea level, 285 km/h at 5000 m, cruising speed 273 km/h , landing speed 96 km/h,  range 700 km, endurance 3 h , service ceiling  8600 m , climb  to 1000 m 1 min, ., to 3000 m 4,8 min Max.. speed  290 km/h at sea level, 277 km/h at 5000 m, landing speed 96 km/h,  cruising speed  , range 700 km, endurance  , service ceiling  7200 m , climb 9,7 m/sec., to 1000 m 2 min., to 3000 m 6,6 min,  360 degrees turn 12 sec., take off run 90 m, landing run 160 m
Armament 2 fixed, forward-firing  machine guns 2 fixed, forward-firing 7 62 mm  PV-1 machine guns
Type Werk.Nr Registration History
a 291 After several testflights it crashed on 20.7.1928 outside Moskow
b 292
Polikarpov I-7 License built at Plant No 1 at Moskow. Total 131 built
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-type interplane 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.

The Soviet Air Force was experiencing a crisis with the obsolescence of its main fighter, the Polikarpov I-5, with no replacement apparently forthcoming from domestic manufacturers. When Heinkel was approached to provide an alternative, 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 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 carried out by TsKB (Tsentrahl'noye konstrooktorskoye byuro - central construction bureau) and Polikarpov, given the designation I-7.

Many of the improvements 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 on-going 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 obsolete.