soviet fighter prototype late 1920s designed traditional wooden construction comparison wood steel tube construction development took longer planned lead designer arrested industrial sabotage delayed project prototypes built selected production design development development fighter began september deadline delivery prototype august prototypes completed new fighter shared characteristics earlier design including single bay layout wings new design cylinder single row air cooled radial engine water cooled engine predecessor designed russian later redesignated russian experimental department aviation trust supervision head designer department originally intended compared changed evaluation construction methods wooden construction compared mixed construction aircraft engine license recently negotiated oval section semi fuselage covered birch small fuselage engine enclosed metal left cylinder heads exposed better cooling wings covered fabric clark profile internal wires fitted reinforce wings control surfaces framed covered fabric type separated wings attached upper wing fuselage profile reinforced steel wires conventional fixed rubber shock wooden propeller given spinner lighter weight air cooled engine required heavy meant weight arrested imprisoned september crime industrial sabotage projects met stipulated delayed flight march second prototype completed shortly aircraft appeared year day fly past moscow aircraft likely imported engines replaced soviet built copy crashed june test pilot justification opinion soviet aviation historian virtually identical performance took seconds complete circle versus seconds aircraft armed machine guns production model expected armed proved impose great penalty performance exact reasons selection debated year known likely relate factors informed selection release initial sentence death years imprisonment labor camp specifications data general characteristics crew length wingspan height wing area weight loaded weight powerplant radial engine performance maximum speed mph range nmi service ceiling wing loading power mass time altitude minutes horizontal turn time sec armament machine guns
Polikarpov I-6