The Polikarpov DI-1 (DI - Dvukhmesnyy Istrebitel - two-seat fighter), also known as 2I-N1, Russian: Поликарпов ДИ-1 (2И-Н1), was a prototype Soviet two-seat fighter designed during the 1920s. The sole prototype built crashed on its ninth flight, due to manufacturing defects, and the program was cancelled.
Nikolai Nikolaevich Polikarpov began design of a two-seat fighter initially designated as the 2I-N1 (two-seat Istrebitel' (fighter) with a single Napier engine) in October 1924 at Zavod (Factory) Nr. 1 at Khodynka Aerodrome, Moscow. It was the first Soviet indigenous two-seat fighter.[1] It was a single-bay biplane with its wings arranged in a sesquiplane configuration. The oval-shaped, semi-monocoque fuselage was made of 'shpon', molded birch plywood. The wings were also covered with 'shpon'. The upper wing had two spars, but the lower wing only had one. Internal bracing wires were not used in the wings as it was built up from plywood ribs with large lightening holes and stringers. V-struts made from Duralumin separated the wings and connected the upper wing to the fuselage. Steel bracing wires were used externally. An airfoil enclosed the axle of the fixed undercarriage and a small ski served as a tailskid. It had an imported 336-kilowatt (451 hp) Napier Lion engine enclosed in a metal cowling. It carried 547 kg (1,206 lb) of fuel and oil. The armament consisted of a single fixed 7.62 mm (0.300 in) synchronized PV-1 machine gun and a 7.62 mm DA machine gun mounted on a ring in the observer's cockpit.[1]
The first flight of the prototype took place on 12 January 1926 and the DI-1, as it was now known, demonstrated excellent performance. Polikarpov himself flew as the observer on the fourth and eighth test flights. However, during the ninth flight on 31 March 1926, the aircraft was making speed runs over the measured kilometer at Khodynka Airfield at a height of 100 metres (328 ft) when the upper surface of the right upper wing ripped off, followed by the lower skin. Both right wings then collapsed and the DI-1 crashed, killing both the pilot, V. N. Filippov, and the observer, V. V. Mikhailov.[2]
Examination of the wreckage revealed that large portions of the wings' skin were badly glued and that a number of rib caps and stringers were not glued at all. Many panel pins were not connected to the structure at all and many of the bradawl holes necessary to equalize pressure between the inside of the wing and the outside were missing entirely. The crash of such an advanced aircraft shocked the entire industry and caused a six-month hiatus in design work. Polikarpov overreacted to its loss and built the structure of a number of his subsequent aircraft stronger, and thus, heavier, than it needed to be.[2] All further work on the project was abandoned following the crash, nominally for lack of a suitable engine.[1]
Specificationsedit
Data fromIstoriia konstruktskii samoletov v SSSR do 1938[3]
polikarpov, dvukhmesnyy, istrebitel, seat, fighter, also, known, russian, Поликарпов, ДИ, prototype, soviet, seat, fighter, designed, during, 1920s, sole, prototype, built, crashed, ninth, flight, manufacturing, defects, program, cancelled, role, fighternation. The Polikarpov DI 1 DI Dvukhmesnyy Istrebitel two seat fighter also known as 2I N1 Russian Polikarpov DI 1 2I N1 was a prototype Soviet two seat fighter designed during the 1920s The sole prototype built crashed on its ninth flight due to manufacturing defects and the program was cancelled DI 1 2I N1 Role FighterNational origin Soviet UnionManufacturer PolikarpovDesigner Nikolai Nikolaevich PolikarpovFirst flight 12 January 1926Status CancelledNumber built 1 Contents 1 Design and development 2 Specifications 3 References 4 Further readingDesign and development editNikolai Nikolaevich Polikarpov began design of a two seat fighter initially designated as the 2I N1 two seat Istrebitel fighter with a single Napier engine in October 1924 at Zavod Factory Nr 1 at Khodynka Aerodrome Moscow It was the first Soviet indigenous two seat fighter 1 It was a single bay biplane with its wings arranged in a sesquiplane configuration The oval shaped semi monocoque fuselage was made of shpon molded birch plywood The wings were also covered with shpon The upper wing had two spars but the lower wing only had one Internal bracing wires were not used in the wings as it was built up from plywood ribs with large lightening holes and stringers V struts made from Duralumin separated the wings and connected the upper wing to the fuselage Steel bracing wires were used externally An airfoil enclosed the axle of the fixed undercarriage and a small ski served as a tailskid It had an imported 336 kilowatt 451 hp Napier Lion engine enclosed in a metal cowling It carried 547 kg 1 206 lb of fuel and oil The armament consisted of a single fixed 7 62 mm 0 300 in synchronized PV 1 machine gun and a 7 62 mm DA machine gun mounted on a ring in the observer s cockpit 1 The first flight of the prototype took place on 12 January 1926 and the DI 1 as it was now known demonstrated excellent performance Polikarpov himself flew as the observer on the fourth and eighth test flights However during the ninth flight on 31 March 1926 the aircraft was making speed runs over the measured kilometer at Khodynka Airfield at a height of 100 metres 328 ft when the upper surface of the right upper wing ripped off followed by the lower skin Both right wings then collapsed and the DI 1 crashed killing both the pilot V N Filippov and the observer V V Mikhailov 2 Examination of the wreckage revealed that large portions of the wings skin were badly glued and that a number of rib caps and stringers were not glued at all Many panel pins were not connected to the structure at all and many of the bradawl holes necessary to equalize pressure between the inside of the wing and the outside were missing entirely The crash of such an advanced aircraft shocked the entire industry and caused a six month hiatus in design work Polikarpov overreacted to its loss and built the structure of a number of his subsequent aircraft stronger and thus heavier than it needed to be 2 All further work on the project was abandoned following the crash nominally for lack of a suitable engine 1 Specifications editData from Istoriia konstruktskii samoletov v SSSR do 1938 3 General characteristicsCrew 2 Length 9 75 m 32 ft 0 in Wingspan 12 m 39 ft 4 in Wing area 27 15 m2 292 2 sq ft Empty weight 1 153 kg 2 542 lb Gross weight 1 700 kg 3 748 lb Powerplant 1 Napier Lion W 12 water cooled piston engine 336 kW 451 hp Propellers 2 bladed fixed pitch propellerPerformance Maximum speed 268 km h 167 mph 145 kn Range 800 km 500 mi 430 nmi Service ceiling 7 100 m 23 300 ft Time to altitude 5 000 m 16 000 ft in 13 minutes Wing loading 63 kg m2 13 lb sq ft Power mass 0 2 kW kg 0 12 hp lb Horizontal turn time 12 secArmament Guns 2 7 62 mm 0 30 in machine gunsReferences edit a b c Gordon and Dexter p 5 a b Gunston p 288 Shavrov V B 1985 Istoriia konstruktskii samoletov v SSSR do 1938 g 3izd in Russian Mashinostroenie ISBN 5 217 03112 3 Further reading editGunston Bill 1995 The Osprey Encyclopedia of Russian Aircraft 1875 1995 London Osprey ISBN 1 85532 405 9 Gordon Yefim Dexter Keith 2002 Polikarpov s Biplane Fighters Hinckley England Midland Publishing ISBN 1 85780 141 5 Retrieved from https en wikipedia org w index php title Polikarpov DI 1 amp oldid 1194346398, wikipedia, wiki, book, books, library,
