|Wing Load (kg/m2)||178|
|Speed at ?m||850km/h|
|Speed at 21000m||M=0.82|
High altitude reconnaissance (so 'RV' for Razvedchick Vysotnyj) version of the Yak-25. Project of this unarmed aircraft started in 1957. Yak-25RV got a new straight wing, having a span of 23.4m (more than twice compared to the predecessor) and area 55m2. As a result, the wing load turned less than for piston-engined Yak-3 fighter.
Test-flights at Flight-Research Institute (LII) (leading test-pilot V.P.Smirnov and test-pilot A.A.Scherbakov) were performed between March 1 and May 29 1959. Performance was quite good (see table), but at altitudes above 19600m sustained flight was not achieved due to engines spontaneous cut-off. Serious critics was addressed to pressurized suite SI-3M. V.P.Smirnov faced another high altitude peculiarity: it was very difficult to get back down due to very high airdynamic quality of the 'glider'. In one of flights pilot had to lower landing gear to force Yak-25RV to return home.
Another problem of aircraft was extremely narrow 'speed corridor' at stratospheric altitudes: difference between maximum (vibrations) and minimal (lost longitudinal stability) was only 10km/h. It imposed very heavy workload on pilots. But VVS Command had no other options, and production started. Yak-25RV and its modifications were in service for 15 years, replaced by high-speed MiG-25 reconnaissance derivatives.
Record flights were performed under designation 'RV':
155 were built, including 81 unmanned Yak-25RV-II.
|Created January 25, 1996
Modified June 22, 1999