|HIGH-ALTITUDE RECONNAISSANCE AIRCRAFT||Virtual Aircraft Museum / USSR / Russia / Yakovlev|
Existence of the Lockheed U-2 was a factor in triggering development of a special Yak-25 version to fly reconnaissance missions at extreme altitudes. The designation derived from Razvedchik vysotnyi, reconnaissance high-altitude. The OKB received a development order in late 1957, and assigned V A Zabora as chief engineer and V P Smirnov as chief test pilot.
The obvious new feature was a totally different wing, without sweepback and with a dramatic increase in span.
The prototype, with callsign Red 75, was assembled at LII and Factory-tested by Smirnov from 1 March to 29 May 1959.
The VVS were not wholly satisfied with the achieved performance, and with the occasional problem caused by the high-altitude environment, but NII-VVS testing was uneventful and eventually 155 series aircraft were delivered in 1961-65 from Factory No. 99 at Ulan-Ude.
Bill Gunston & Yefim Gordon "Yakovlev Aircraft since 1924", 1997