Yakovlev Yak - 25 ( 1947 ) The Yakovlev Yak - 25 was a Soviet military aircraft , an early turbojet - powered interceptor aircraft designed by the Yakovlev OKB . The designation was later reused for a different interceptor design . Tasked by the Council of Ministers in a directive issued on 11 March 1947 , with producing a straight winged fighter similar to the earlier Yak - 19 , but powered by a Rolls - Royce Derwent V , OKB - 115 swiftly produced the Yak - 25 , which blazed several trails as the first Soviet fighter with a fully pressurised cockpit , air conditioning , jettisonable canopy , and hydraulic airbrakes on the fuselage amongst other innovations . Development . The Yak - 25 closely followed the Yak - 19 in layout if not in detail . The straight wings , though similar in planform , were fractionally larger and much thinner ( 9 % t / c throughout ) , using laminar flow sections . The CAHI flaps were also hydraulically powered . The vertical tail unit differed from the Yak - 19 in being swept back at 40° on the leading edge , while the horizontal tail was swept back at 35 degrees . The Derwent V engine was attached to the rear of the centre fuselage in a manner similar to the Yak - 19 . Though the fuselage had a different non - circular cross - section from the Yak - 19 , a similar double bulkhead directly behind the wing allowed the rear fuselage to be completely removed , giving access to the engine for removal or maintenance . The undercarriage was very similar to the Yak - 19 . The cockpit was very similar to the earlier Yakovlev jets , though the Yak - 25 was pressurized using an air - cycle system based on engine bleed . The single aft sliding canopy was powered . The bullet - proof front windscreen was 57mm thick , while 8mm of armor protected the pilot from behind . The ejection seat was an improvement over the Yak - 19 , with a longer stroke gun , and leg restraints . Armament was also improved , with three NR - 23 cannon , each with 75 rounds . Testing . The Yak - 25 - I was given callsign " yellow 15 " , and had a number " 2 " painted on the airbrake rudder . It was flown in factory testing by Anokhin between 31 October 1947 and 3 July 1948 . Flight tests followed quickly , and showed that the Yak - 25 was easy to fly , and had exceptional performance and maneuverability for a straight - wing aircraft . Unfortunately it soon became clear that the laminar flow section used for the tail unit was totally unsuitable , with extremely severe buffeting setting in at 500 km / h ( 310 mph ) . Test pilot L . L . Selyakov reporting that the buffeting was so bad that he was thrown about the cockpit , banging his head on the canopy , and the needles fell off all the flight instruments . To cure the buffeting the tail unit was replaced with one using a NACA 004 aerofoil section . Worse yet , both of its rivals , the Lavochkin La - 15 and rival swept - wing MiG - 15 had superior performance . The Mig - 15 was selected for mass production . Yakovlev was never again to build a single - engine fighter superior to the rival aircraft coming from Mikoyan , though neither was Lavochkin . Development was halted , but two of the prototypes were used for test and development purposes . Surprisingly , the Yak - 25 never received an ASCC reporting name or USAF type number despite being known to the west at the time . Experimental work . Further development , replacing the straight wing with one of 35° sweepback , was undertaken as the Yak - 30 . Yak - 25E . The Yak - 25E ( Eksperimentalnyi ) was the Yak - 25 - I specially modified to be towed by a Tupolev Tu - 4 strategic bomber . This came in response to a proposal by the headquarters of Long Range Aviation , calling for a method of towing short - range jet fighters , code - named " Burlaki " ( barge hauler ) . Production aircraft would have used Klimov RD - 500 engines . At the same time the Soviets were developing the Yak - 25E , the U . S . Air Force was experimenting with a similar system known as Project Tom - Tom . The U . S . system would have employed either a specially modified F - 84 or a XF - 85 Goblin parasite aircraft . Early attempts differed by attaching two fighters to the bomber ' s wingtips . Later plans called for a parasite aircraft to be stowed internally within the belly of a B - 36 .