Ye-150 and Ye-152 Series

Ye-150

The Ye-150 experimental prototype was designed as a test bed for the new Mikulin/Tumanskiy R-15-300 turbojet. The intent of the aircraft – plus-engine project was to lay the foundation for a new generation of interceptors. The aircraft was designed to fly at speeds of about 2,800 km/h (1,510 kt) and altitudes of 20,000 to 25,000 m (65,600 to 82,000 feet).

The initial plan called for the new engine to be tested on a remote­ly controlled aircraft. This turbojet had a veiy short lifetime, but in that brief period it was powered up on the test bench, examined in flight, and even used to power a missile. It had a dry thrust of 6,705 daN (6,840 kg st) and a reheated thrust of 9,945 daN (10,150 kg st); its after­burner also had a second-stage nozzle called an ejector that supplied 19,405 daN (19,800 kg st) of thrust at Mach 2.4-2.5 and helped to clean up the base drag. For components particularly sensitive to the thermal

stresses (aerodynamic heating) that were the result of high speeds, the manufacturers decided to use heat-resistant materials such as stainless steel in place of duralumin.

The fuselage was shaped like a cylinder 1,600 mm in diameter except at the rear, where the diameter increased to 1,650 mm in the afterburner/ejector area. The shock cone in the engine air intake had a triple-angle profile and was made of dielectric material to house the antenna for the Uragan-5 interception system. The flow rate in the air inlet duct was controlled by a two-position translating ring. As soon as the aircraft reached Mach 1.65 the ring moved forward automatically; once the aircraft dropped back under that speed, the ring returned to its primary position.

The delta wing had a sweepback of 60 degrees at the leading edge, a thickness-chord ratio of 3.5 percent, Fowler-type flaps, and two-part ailerons with balance surfaces at the trailing edge. The wing could be fitted with two pylons for air-to-air missiles. The gear kinematics were standard: the nose gear strut retracted forward into the fuselage, and the main gear wheels also retracted into the fuselage while their struts folded into the wing. The cockpit was equipped with a curtain-type ejection seat. The fuel system included five fuselage tanks with a total capacity of 3,2701 (863 US gallons) plus two wet wing tanks that carried 245 1 (65 US gallons) apiece. The stabilator controls were boosted by two BU-65 power units, and those of the ailerons and rudder by two BU-75 power units. There were two separate hydraulic systems, one primary circuit and one for the servo-controls. The main circuit served the gear, the flaps, the three airbrakes on the underside of the fuselage, the translating ring on the air intake, and the surge bleed valve (on the fuselage sides) while also acting as a backup for the servo-control units. The PT 5605-58 tail chute measured 18 m2 (193.7 square feet). The cockpit hood was made of T2-55 glass, a 12-mm-thick material capable of withstanding 170° C (338° F) in aerodynamic heating.

The Ye-150 rolled out in December 1958 and was first piloted by A. V. Fedotov on 8 July 1960. During the fourth flight, on 26 July, aileron flutter was observed at Mach 0.925. The problem was quickly solved by fitting a damper on the aileron controls. After the fifth flight the tests had to be suspended because the casing of the engine gearbox had cracked. Tests resumed on 18 January 1961 with a brand-new R-15-300 turbojet. From 21 January to 30 March the aircraft made eight more flights and reached Mach 2.1 at 21,000 m (68,900 feet). After a second engine change, the Ye-150 made another twenty flights and hit a top speed of Mach 2.65 at 22,500 m (73,800 feet). At that point the ejector was replaced and the cockpit’s thermal insulation improved; tests resumed on 14 November 1961 and ended on 25 January 1962. There were forty-two flights altogether. Tests of the Uragan-5 complex with two K-9 missiles were not carried out until the Ye-152 A was ready a lit­tle later.

Specifications

Span, 8.488 m (27 ft 10.2 in); overall length (except probe), 18.14 m (59 ft 6.2 in); fuselage length (except cone), 15.6 m (51 ft 2.2 in); wheel track, 3.322 m (10 ft 10.8 in); wheel base, 5.996 m (19 ft 8 in); wing area, 34.615 m2 (372.6 sq ft); empty weight, 8,276 kg (18,240 lb); take­off weight, 12,435 kg (27,405 lb); fuel, 3,410 kg (7,515 lb); wing loading, 359.2 kg/m2 (73.6 lb/sq ft); max operating limit load factor, 5.1.

Performance

Max speed, 1,210 km/h (653 kt) at sea level; 2,890 km/h at 19,000 m (1,560 kt at 62,300 ft); climb to 5,000 m (16,400 ft) in 1 min 20 sec; to

20,0 m (65,600 ft) in 5 min 5 sec; service ceiling, 23,250 m (76,260 ft); landing speed, 275-295 km/h (148-160 kt); endurance, 1 h 50 min; range, 1,500 km (930 mi); takeoff roll, 935 m (3,065 ft); landing roll, 1,250 m (4,100 ft).