The Yak-121 prototype was developed as a successor to the Yak-25 family and it became the base for the Yak-27 family of supersonic interceptor and tactical reconnaissance aircraft. The Yak-27 and Yak-27K interceptors, armed with guns and K-8 missiles respectively, reached or exceeded their requirements, but were overtaken in performance by the Sukhoi Su-9, and so production was not authorized. A high-altitude interceptor version, the Yak-27V, was converted from the Yak-121 prototype by fitting a 1,300 kg•f Dushkin S-155rocket booster in the rear fuselage, and Tumansky RD-9AKYeafterburningturbojets. Although performance was very good, reaching the height of 23,000 m during trials, development was halted due to maintenance problems of the Dushkin S-155 rocket engine. The dedicated high-altitude photo-reconnaissance variant of the Yak-27 interceptor was named Yak-27R. The radome and radar were replaced with a glazed nose for an observer/navigator, two cameras were added, and the Nudelman-Rikhter NR-23 cannon was deleted from the port-board. It had a longer wing with a span of 11.82 m, with two Tumansky RD-9AF turbojet engines and a top speed of about 1,285 km/h at high altitude. It had a service ceiling of 16,500 m and a range of 2,380 km with two wing tanks. About 180 aircraft were produced in Plant No.292 in Saratov.
Operational history
The Yak-27R entered service with the Soviet Air Force in 1960 and was intended to replace the subsonicIlyushin Il-28 reconnaissance aircraft. However, despite the greater speed and ceiling, it had less range. The Yak-27R also had some operational limitations and was flown at supersonic speed only by the most experienced pilots. The low position of the engines made them prone to foreign object ingestion from unimproved forward-base runways. With the increasing coverage of anti-aircraft missiles over Europe, the high-altitude Yak-27R was often more limited than the Il-28. The Yak-27R was withdrawn from operational service in the early 1970s, and was replaced by the Yak-28R and the MiG-25R.
A Yak-27R is preserved at the Central Air Force Museum at Monino, outside of Moscow, Russia. There are also another two airframes preserved in Germany, one at Hugo Junkers Museum Dessau and the other at Speyer Technic Museum, however the latter is in poor condition.
