The Yakovlev Yak-52 (Russian: Яковлев Як-52) is a Soviet primary trainer aircraft which first flew in 1976. It was produced in Romania from 1977 to 1998 by Aerostar, as Iak-52, which gained manufacturing rights under agreement within the former COMECON socialist trade organisation.[1] The Yak-52 was designed as an aerobatic trainer for students in the Soviet DOSAAF training organisation, which trained civilian sport pilots and military pilots. Currently the Yak-52 is used in the Fédération Aéronautique Internationale (FAI) World Aerobatic Yak 52 Competition, a popular powered aircraft one-design World Aerobatic Championship.[2]
Since the aircraft was designed to serve as a military trainer, the development of the aircraft incorporates a number of features to be found on the early postwar fighters: notably the cockpit tandem layout (instrument panel, seat design, cockpit opening system), tail design, tricycle landing gear, fuselage mixed construction (monocoque with steel tube construction), inner flaps, controls position, access panels on sides of the fuselage, even the location of the radio antenna and overall dimensions of the airplane, which extensively match the Yakovlev Yak-17 UTI jet fighter trainer (NATO code name Magnet).
The aircraft has fuel and oil systems permitting inverted flight for as long as two minutes. The engine drives a two-bladed counter-clockwise rotating, variable pitch, wood and fiberglass laminate propeller.
At 998 kg (2,200 lb) empty weight, the Yak-52 is responsive and very capable as an aerobatic aircraft. Yet it is also easy to fly and land. It has been used in international aerobatic competition up to the Advanced level. It is stressed to +7 and –5 Gs, rolls (to the right) at well more than 180 degrees/second (measured up to 352 degrees/second to the right), and is capable of every manoeuvre in the Aresti catalog.
The Yak-52, like most Soviet military aircraft, was designed to operate in rugged environments with minimal maintenance. One of its key features, unusual in western aircraft, is its extensive pneumatic system. Engine starting, landing gear, flaps, and wheel brakes are all pneumatically actuated. Spherical storage bottles for air, replenished by an engine driven compressor, are situated behind the rear cockpit and contents displayed on the instrument panels. The operating pressure is between 10 and 50 bars (145 and 725 psi) and an emergency circuit is reserved for lowering the undercarriage if the normal supply is exhausted or the compressor fails. Additionally both main and reserve bottles can be charged from a port on the ground with compressed air, usually from a scuba type air bottle. The ground steering/braking arrangement, especially, takes some adjustment for flyers accustomed to hydraulics, because the aircraft uses differential braking controlled by rudder pedals and a hand-operated lever on the control stick.
The tricycle landing gear is retractable, but it remains partially exposed in the retracted position, affording both a useful level of drag in down manoeuvres and a measure of protection should the aircraft be forced to land "wheels up."
A number of "westernised" versions of the Yak-52 are now produced. The replacement of the existing Soviet avionics, fitting of a three-blade propeller and the M14PF 298 kW (400 hp) upgrade to the usual 360 hp M14P engine, and conversion to conventional "tail-dragger" landing gear (Yak-52TD) are some of the modifications made to the standard aircraft. There is also a factory-produced Yak-52TW tail-dragger version by Aerostar. The TW has an extra 120 L (32 US gal) of fuel capacity in two extra wing tanks, the M14PF engine designated & three blade propeller, an electric start, and modern instruments.
On April 16, 2004, a modernised variant Yak-52M was flown in Russia. It is fitted with modernised M-14Kh engine, three-blade propeller, and other modifications.
Variants
Aerostar Iak-52
Yak-52
Two-seat primary trainer aircraft, powered by a 360-hp (268-kW) Vedeneyev M-14P nine-cylinder radial piston-engine.
Yak-52B
Two-seat light ground-attack aircraft, armed with two UB-32-57 rocket pods, each capable of carrying up to 32 air-to-ground S-5 rockets.[citation needed]
Yak-52M
2003 modernised version, powered by a Vedeneyev M-14Kh radial piston engine. It is fitted with a three-bladed propeller, new avionics and crew escape system.[3]
Iak-52
Romanian designation of Yak-52[4] produced by Aerostar.
Aerostar Condor
Westernised version proposed by Aerostar, powered by Lycoming O-540 engine.[4]
Iak-52W
Westernised version produced by Aerostar, powered by M-14P or M-14Kh engine, but with all western instruments installed.
Iak-52TW
Westernised version produced by Aerostar, powered by M-14P or M-14Kh engine and tail wheel instead of front wheel. This version has all-western instruments, deeply modernised wing that provide retraction of mainwheels (hydraulic brake components and portioins of main gear strut still extend below wing), also, enlargement of fuel tanks volume up to 280 L.
Iak-52TD
Modified Yak-52 with more powerful M-14PK engine and a tailwheel configuration by Termikas Ltd in Lithuania. Modifications include a set of wings with integrated aerobatic and ferry tanks (total capacity 230 litres), and allow complete retraction (no portions of the gear/main strut extend below wing structure). Bulletin 60 (strong joint fittings of the main spar) and Bulletin 107 (steel strap on the main spar installed) also completed at modification.
Military operators
DOSAAF Yak-52Iak-52TW at Pauanui, New ZealandYak-52 front cockpitYak-52B at Monino Air Force museum
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