Spinners Posted August 19, 2013 Posted August 19, 2013 (edited) Bereznyak-Isayev-Bratukhin BIB-20R - PVO Strany, 1955 Despite the failure of the wartime Soviet rocket-powered development and prototype aircraft, principally by Bereznyak-Isayev and Polikarpov, in 1946 Stalin demanded a new fast-climbing rocket-powered 'Blizhnii Istrebitel' or point defense fighter as a last line of defence against the perceived threat of US bombers armed with atomic bombs. With Stalin's blessing the remains of the Bereznyak-Isayev design team formed an alliance with the Bratukhin design bureau (formed in 1940 to produce helicopters) and with input from TsAGI set about creating a rocket-powered interceptor. Almost immediately the new Bereznyak-Isayev-Bratukhin design team realised the inflexibility of an aircraft only powered by rocket engines and set about creating a more flexible design with a single axial-flow turbojet engine supplemented by booster rockets. Designated BIB-20 the design initially had a straight wing with two large wingtip mounted rocket boosters before being extensively redesigned with swept wings and four smaller booster rockets initially clustered around the rear fuselage before later being relocated beneath the main fuselage. However, fears over tip stall led to a further redesign with the wings now having more chord at the wingtip than the wingroot in an attempt to generate more lift and delay the point of stall at the tip to that of the entire wing. The design also meant that the wingtips had more internal room enabling the landing gear to be mounted to retract outwards and allow fuel to be located in integral inner wing tanks that also boosted the torsional resistance of the wing to counter the additional outboard mass of the 'inverse taper' wing. The prototype BIB-20 first flew on May 1st, 1949 piloted by Konstantin Gruzdev and powered solely by a Lyulka TR-3A single-shaft turbojet with a seven-stage axial compressor developing 5,500lbs of thrust. By the Autumn of 1949 the BIB-20 prototype had been retrofitted with four RD-1KhZ rocket engines each developing about 660lbs thrust and the first flight of the BIB-20R took place on November 7th, 1949 with Vasily Pliyev at the controls. On the modest power of the early engines the performance of the BIB-20R was quite unimpressive at low altitudes but was much improved at higher altitudes with the rocket engines enabling altitudes in excess of 60,000ft to be achieved and later versions with more powerful RD-2 rocket engines rated at 1,500lbs thrust each saw operational aircraft reach 65,000ft with outstanding rate of climb. Entering service in late 1953 the BIB-20R was hailed by the Soviet Union as a massive technical achievement but in reality the type suffered from very poor range and very high maintenance and with the MiG-19S entering service before the end of 1954 it was soon phased out in favour of more conventional types. Edited August 20, 2013 by Spinners Quote
Geary Posted August 19, 2013 Posted August 19, 2013 (edited) Beauty. Good to see it repurposed and those odd marshmallow skewers removed from the front. Edited August 19, 2013 by GearyMcS Quote
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