heavily armed soviet heavy fighter designed early 1940s prototypes built intended engines proved unreliable placed production engines manufacturer lacked resources fix problems second prototype crashed september program canceled death chief designer eponymous earlier year design development original request proposals heavy escort fighter received november press work prototypes prevented significant design work quarter appointed head designer job complicated multiple changes role aircraft escort fighter dive bomber eventually reconnaissance prototype internally designated aircraft low wing metal engines twin tail fuselage machine guns nose rounds pilot gunner radio operator seated separated armor plate sliding gunner dorsal mount rounds canopy slid forward ventral mounted armored floor access raising hatch floor kneeling fire machine guns ventral gun provided rounds ammunition machine gun rounds cannon rounds mounted wing root underneath wings racks capable carrying single bomb wing automatic leading edge split flaps separated engine single wheel landing gear retracted rear fuselage prototype flew september reached speed mph altitude suffered lack directional stability engines unreliable factory attempted fix stability problem late september increasing area rear fins unsuccessful flight testing continued october russian evacuated eliminating stability problem took march engines remained unreliable summer clear lacked resources fix problems need new engine resources fully utilized programs program hold work resume second half canceled engine selected new prototype built internally called completely revised armament cannon replaced nose machine guns machine gun mount replaced dorsal ventral machine gun removed entirely cannon replaced wing root guns intended unavailable temporary engine moved wings fed leading edge outlets wing operational history flight tested june september generally met expected performance figures engines low altitudes aircraft reach maximum speed mph ceiling metres initial climb rate basis flight tests concluded capable reaching mph minutes reach metres fitted brake failure june damaged required month repair crash landing september caused failure extend proved death program shut death end june willing champion specifications data encyclopedia russian aircraft general characteristics crew length wingspan height wing area weight gross weight fuel capacity imp gal gal powerplant liquid cooled engines propellers bladed performance maximum speed mph range nmi service ceiling time altitude minutes armament guns cannon wing roots machine guns wing roots machine guns nose machine guns mounted bombs
Polikarpov TIS