Yakovlev Yak-36

Yakovlev Design Bureau

Industry	Aerospace
Founded	1960
Headquarters	Soviet Union
Products	Aircraft, including the Yakovlev Yak-36 experimental VTOL jet

Template:Infobox aircraft

The Yakovlev Yak-36, also referred to as Izdeliye V and identified by the (NATO reporting name "Freehand"), served as a Soviet experimental platform designed to validate technologies for a VTOL combat jet.

Design and development

Starting in 1960, the Yakovlev Design Bureau initiated efforts to develop a VTOL solution utilizing the compact Tumansky RU-19-300 turbojet engine. They initially conceived the Yak-104, which was a modified version of the Yak-30 jet trainer. This design incorporated two vertically oriented Ru-19 engines positioned between the air intakes of the standard Yak-30's powerplant. However, development on the Yak-104 was discontinued in favor of pursuing an aircraft powered by a single lift/cruise engine equipped with swiveling nozzles, akin to the Hawker Siddeley P.1127 then being finalized in England. Due to difficulties in securing an appropriate engine or government approval for its development, Yakovlev was compelled to adopt an alternative approach.

In response to a 1961 contract calling for a single-seat V/STOL fighter, Yakovlev proposed a twin-engine design featuring a large air intake at the nose, with engines housed in the forward fuselage and swiveling exhaust nozzles—one per engine—located on either side of the lower fuselage near the aircraft’s center of gravity. Although the fighter variant did not proceed into production, four technology demonstrators, initially labeled Izdeliye V, were commissioned based on this concept.

A total of four prototypes were constructed. One prototype was dedicated solely to static testing. Another was utilized for takeoff and landing trials, including free hover maneuvers. The third incorporated enhancements identified during earlier tests, such as an improved autopilot system that automatically optimized airflow for hover stability; this prototype experienced a crash but was subsequently repaired. The fourth prototype was lost in a crash in February 1971 and was not restored.

Construction

The aircraft featured a semi-monocoque fuselage combined with bicycle-style landing gear. Its wings were short, cropped delta types with a leading edge swept back at 37°, incorporating a 5° anhedral angle, and were mounted mid-fuselage. Forward of the wing trailing edges, the fuselage was considerably bulky to house the engines, cockpit, fuel tanks, and equipment compartments as close as possible to the aircraft's center of gravity. It then tapered sharply towards the swept tail surfaces, which included a high-mounted tailplane. Flight control was managed through traditional rudder, ailerons, and elevators during standard flight conditions, while compressed engine bleed air was expelled from control nozzles located at the wingtips, rear fuselage end, and at the tip of an extended boom projecting forward from the upper lip of the air intakes.

The Yak-36 was equipped with two underwing hardpoints capable of carrying bombs, machine gun pods, or rocket pods. However, it lacked sufficient surplus thrust and operational range to function effectively as a combat aircraft.

Operational history

The initial tethered hover test occurred on 9 January 1963. Early challenges included hot gas reingestion, where exhaust gases were drawn back into the intakes, resulting in disrupted engine airflow and thrust reduction. Additional complications arose from exhaust suction effects near the ground—which demanded higher engine power—and issues within the control systems. Following adjustments, the aircraft achieved its first untethered vertical flight on 23 June 1963. This milestone was followed by the initial complete transition to horizontal flight on 16 September 1963.

On 24 March 1966, the Yak-36 completed its inaugural full flight cycle involving vertical takeoff, transition to horizontal flight, deceleration back to vertical flight, and vertical landing. After extensive testing and refinement, the aircraft was publicly showcased for the first time on 9 July 1967 during an airshow at Moscow-Domodedovo Airport, commemorating the 50th Anniversary of the October Revolution. Encouraged by the promising outcomes from its flight test program, development advanced to the Yakovlev Yak-36M variant, which first flew on 27 September 1970.

Operators

Template:USSR

• Soviet Air Force

Aircraft on display

The second prototype of the Yak-36, bearing bureau number 35, is exhibited at the Central Air Force Museum located in Monino, near Moscow, Russia.

Specifications (Yak-36)

File:GVG Yak-36 3-view.png

Orthographic projection diagram of the Yakovlev Yak-36.

External links

• The preserved Yak-36 displayed at Monino