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Yakovlev Yak-50

Yak-50

Manufacturer: Yakovlev
First flight: July 1949
Status: Cancelled
Primary user: Soviet Air Forces

Yakovlev Yak-50 was an early experimental turbojet interceptor aircraft designed in 1948 by the Yakovlev OKB in USSR. The aircraft was essentially a stretched version of the Yakovlev Yak-30 (1948), with a more powerful engine and greater sweep to the wings. The Yak-50 is perhaps most significant as the first Yakovlev aircraft equipped with the velosipednoye (bicycle) landing gear, a trademark of later Yakovlev designs. The Yak-50 designation was later reused for a propeller-driven aerobatic and trainer aircraft.

History

On February 21, 1949 a Sovmin order requested the Yakovlev OKB to design a lightweight, radar-equipped, all-weather and night interceptor capable of Mach 0.97 at 4,000 m (13,000 ft). The aircraft was to utilize the Klimov VK-1 engine which first appeared on Mikoyan-Gurevich MiG-15 and MiG-17 fighters. This engine was itself a Soviet copy of the British Rolls-Royce Nene centrifugal turbojet initially known as the RD-45. The leading fighter OKBs each created a prototype to meet the requirement, which included the La-200, MiG I-320, Su-15 (unrelated to the later aircraft with the same designation) amd the Yak-50 (again, unrelated to the later aircraft). A major difference was that while Yakolev used one engine, the other design bureaus used two.

Development

In almost all respect the Yak-50 was a modified version of the Yak-30. The wing was swept back at 45 degrees, a remarkable figure for the time, and had a thickness of 12%. Each wing had three shallow fences, the inboard pair being full-cord, and the outer one stopping ahead of the ailerons and hydraulically boosted. The wing spars could be unbolted from the wing root allowing either wing to be removed. The fixed tailplane had the same sweepback as the wing and the same profile as the vertical tail.

The engine was the VK-1 rated at 2,700 kgf (5,950 lbf, 26.5 kN) thrust. A total of 1,065 liters (234 imperial gallons) of kerosene was housed in protective tanks.

One totally new feature was the use of a velosipednoye (bicycle) landing gear, with the main units located along the centerline. The two units retracted forward into a bay, and supported 85% of the aircraft's weight. Small outrigger gear were fitted to each wingtip, which retracted backward into tip fairings.

The cockpit was pressurized, with a bulletproof forward windscreen. The canopy slid to the rear, and the cockpit was fitted with an ejection seat with a firing handle on each side. Back armor was 8mm thick. Radar was a Korshun (Kite, the bird) type unit, with a single mechanically-driven scanner, while a RSIU-3 radio and RPKO-10M radio compass were also fitted. Armament was two NR-23 cannon with 80 rounds each. A duplicate pneumatic system with bottles charged the undercarriage, flaps, wheel brakes and airbrakes.

The first prototype, Yak-50-I, had callsign "20" and the number "3" painted on the lower fin. On the lower rear fuselage were left and right ventral strakes set at 90 degrees to the skin. The radar and top of the nose were painted black.

Testing

The aircraft first flew on 15 July 1949, with test pilot Anokhin achieving supersonic speed (Mach 1.03 at 10,000 m (33,000 ft)) in a shallow dive during one of the test flights. The Yak-50 was delivered for government testing in June 1950. In the course of the evaluation the aircraft was commended for excellent performance, but a number of deficiencies were also noted. In particular, the airbrakes were ineffective, there was significant yaw at transsonic speeds making accurate gunfire impossible, and the aircraft was difficult to land in significant crosswinds, and impossible on wet or icy runways. In addition, the aircraft did not meet the original requirement that the armament be two 23 mm cannon and one 37 mm. The radar, developed by the newly-formed OKB of A B Slepushkin, was so difficult to interpret that a second crewmember was considered.

Eventually the second prototype, Yak-50-II, joined the first, with a single deeper underfin along the centerline. This aircraft had callsign "35", and the number "2" painted on the fin.

Ultimately, none of the newly developed aircraft was selected, and an upgraded MiG-17 was eventually employed. Yakolev later used the velosipednoye landing gear in the Yak-140 fighter and the Yak-120, and later in the Yak-25 and Yak-28 where it proved highly successful.

The Yak-50 never received an ASCC name or USAF reporting number.

Operators

Soviet Union

Soviet Air Force

Specifications

General characteristics

Crew: 1
Length: 11.12 m (36 ft 6 in)
Wingspan: 8.01 m (26 ft 3 in)
Height: ()
Wing area: 16.0 m² (172.2 ft²)
Empty weight: 3,085 kg (6,787 lb)
Loaded weight: 4,155 kg (9,141 lb)
Powerplant: 1x— Klimov VK-1 centrifugal compressor turbojet engine, 26.5 kN (5,940 lbf)

Performance

Maximum speed: 1,120 km/h (696 mph)
Range: 850 km (528 mi)
Service ceiling: 16,050 m (52,600 ft)
Rate of climb: 68 m/s (13,400 ft/min)
Wing loading: 260 kg/m² (53 lb/ft²)
Thrust/weight: 0.65

Armament

2x— 23 mm Nudelman-Rikhter NR-23 cannons, 80 rounds/gun

Related development

Yakovlev Yak-30 (1948)
Yakolev Yak-140

Comparable aircraft

Mikoyan-Gurevich MiG-17
F-94 Starfire
F-86D
Dassault Mystx¨re II
Dassault Mystx¨re IV

Related lists

List of military aircraft of the Soviet Union and the CIS

Gunston, Bill. Yakovlev Aircraft since 1924. London, UK: Putnam Aeronautical Books, 1997. ISBN 1-55750-978-6.

Living Warbirds: The best warbirds DVD series.

Source: WikiPedia