Ye-6T/l (Ye-66A)

In 1960 the Ye-6T/l, the first true series-built MiG-21, callsign Red-31, was rebuilt for record purposes, with various modifications. In order not to reveal too much to the FAI in­ternational body, it was given the invented designation Ye-66A. The most obvious change was to attach a rocket package un­derneath the fuselage. The rocket engine was designated S-3/20M5A, the ultimate version of Dushkin’s family burning kerosene and RFNA fed by peroxide turbopumps. The propellants were packaged with the engine and control system in a large gondola designated U-21. Thrust was 3,000kg (6,614 Ib) at sea level, ris­ing to about 3,700kg (8,150 Ib) at high altitude. The rocket nozzle was angled 8° downwards, but despite this it was necessary to replace the usual MiG-21 underfin by two shorter but deeper ventral fins each inclined outwards. The main engine was replaced by an R-l 1F2- 300, with a maximum afterburning rating of 6,120kg (13,492 Ib); this engine later became standard on the MiG-21 PF. Other modifica­tions included 170 litres (37.4 Imperial gal­lons) of extra kerosene fuel in a spine fairing behind the canopy, and a fin extended for­wards to increase area of the vertical tail to 4.44m2 (47.7ft2). The Ye-66A did not set any ratified speed records, but on 28th April 1961 it was flown by G K Mosolov in a zoom to a new world absolute height record of 34,714m (113,891ft). He made a low flypast with rock­et in operation at the airshow at Moscow Tushino on Aviation Day (9th July) 1961.