The Yakovlev Yak-52 is an aircraft that was primarily designed for training purposes in the Soviet Union.
Its maiden flight took place in 1976, and it was subsequently manufactured in Romania by Aerostar from 1977 to 1998 under the name Iak-52.
This production was made possible through an agreement within the former COMECON socialist trade organisation, which granted manufacturing rights to Aerostar.
The Yak-52 was specifically developed as an aerobatic trainer for students enrolled in the Soviet DOSAAF training organisation, which catered to both civilian sport pilots and military pilots.
The Yak-52 is a descendant of the single-seat competition aerobatic Yakovlev Yak-50, and is an all-metal aircraft powered by a 268 kW (360 hp) Vedeneyev M14P nine-cylinder radial engine.
The aircraft was designed to serve as a military trainer, and as such, incorporates a number of features found on early postwar fighters, including a cockpit tandem layout, tail design, tricycle landing gear, fuselage mixed construction, inner flaps, controls position, access panels on sides of the fuselage, and the location of the radio antenna.
The aircraft has fuel and oil systems that permit inverted flight for up to two minutes, and is equipped with a two-bladed counter-clockwise rotating, variable pitch, wood and fiberglass laminate propeller.
With an empty weight of 998 kg (2,200 lb), the Yak-52 is highly responsive and capable as an aerobatic aircraft yet is also easy to fly and land.
It has been used in international aerobatic competition up to the Advanced level and is capable of every manoeuvre in the Aresti catalogue.
The aircraft is stressed to +7 and –5 Gs, and rolls (to the right) at well over 180 degrees/second (measured up to 352 degrees/second to the right).
The Yak-52 was designed to operate in rugged environments with minimal maintenance and features an extensive pneumatic system.
Engine starting, landing gear, flaps, and wheel brakes are all pneumatically actuated, with spherical storage bottles for air replenished by an engine-driven compressor situated behind the rear cockpit.
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.
The ground steering/braking arrangement uses differential braking controlled by rudder pedals and a hand-operated lever on the control stick.
The tricycle landing gear is retractable, but 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, including the Yak-52TD, which features conventional “tail-dragger” landing gear, and the Yak-52TW, a factory-produced tail-dragger version by Aerostar with extra fuel capacity, an upgraded engine, and modern instruments.
On April 16, 2004, a modernised variant Yak-52M was flown in Russia, featuring a modernised M-14Kh engine, three-blade propeller, and other modifications.
Variants
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.
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.
Iak-52
Romanian designation of Yak-52 produced by Aerostar.
Aerostar Condor – Westernised version proposed by Aerostar, powered by Lycoming O-540 engine.
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 complete retraction of main wheels and, also, enlargement of fuel tanks volume up to 280 l.
Yak 53
The sole prototype of the Yakovlev Yak-53, a single-seat aerobatic trainer aircraft, was manufactured in the Soviet Union between 1981 and 1982.
The Yak-53 prototype was developed as an aerobatic trainer, based on the Yak-52 model.
It was designed as a single-seater aircraft, with modifications made to the canopy and the removal of the front cockpit.
The flying controls of the Yak-50 were utilized in the cockpit, without the spring loading of the Yak-52.
Additionally, the undercarriage and tankage of the Yak-52 prototype were incorporated to reduce weight, resulting in the Yak-53 being 100 kg (220 lb) lighter than its predecessor.
On the 15th and 23rd of February in 1982, the Yak-53 prototype achieved two world records for time to height within its category.
According to certain sources, the record-breaking flights were accomplished with the assistance of a 3-bladed propeller of western origin.
190 km/h (120 mph, 100 kn) at 1,000 m (3,300 ft) (econ cruise)
Stall speed
85–90 km/h (53–56 mph, 46–49 kn) flaps down, engine idling
Never exceed speed.
360 km/h (220 mph, 190 kn)
Range
550 km (340 mi, 300 nmi) at 500 m (1,600 ft)
Service ceiling
4,000 m (13,000 ft)
G limits
+7/-5
Rate of climb
5.00 m/s (985 ft/min)
Time to altitude
15 min to 4,000 m (13,000 ft).
Sources Yakovlev Aircraft Since 1924 – Bill Gunston & Yefim Gordon. OKB Yakovlev, A History of the Design Bureau and Its Aircraft-Yefim Gordon, Dmitriy Komissarov & Sergey Komissarov. Soviet Aircrafts Illustrated-A.S.Yakovlev.
