TYPE: Primary prop trainer/sportplane.
PROGRAMME: Design of Yak-52 in USSR began 1975; series production assigned to Comecon programme (Council for Mutual Economic Assistance), following Romanian-USSR intergovernmental agreement of 1974; designation is transliteration of 'Yak' in Romanian alphabet, but civil aircraft are registered as Yaks.
Construction began 1977 and first Romanian prototype (c/n 780102) made first flight May 1978; series production began 1979; first deliveries (to DOSAAF, USSR) 1975; 1,000th aircraft delivered in 1986 and 1,500th in 1990. After cessation of deliveries to USSR in 1991, production had almost come to a standstill, but interest reawakened by improved Iak-52W (first flight April 1999, debut at Paris Air Show, June 1999). Iak-52W began development 1998 and first flew (12201) March 1999; currently offered as alternative to standard version. Aerostar planned five-year programme of 30 per year; deliveries started August 1999. Tailwheel (TW) version announced early 2000; first flew '26', c/n 0112226, later n52SD) 2 July 2001; launched at EAA AirVenture, Oshkosh, 24 to 30 July 2001.
CURRENT VERSIONS: Iak-52: Standard model.
Full description of standard Iak-52 follows, augmented by details of Iak-52W and TW, where different.
Iak-52W: Upgraded ('Westernised') version; introduced 1999. Main changes are increased fuel tankage, three-blade propeller, Western avionics, and metal-skinned control surfaces. No known deliveries since 2001, but some believed held in stock.
Iak-52TW: Tailwheel version of Iak-52W, revealed early 2000. Production aircraft available from July 2001 (four sold by end of first day of promotion at Oshkosh); US marketing by GeSoCo Industries of Swanton, Vermont, USA. Features include extended (rounded) wingtips, uprated engine with underslung oil radiator and modified front shutters; each cockpit lengthened by 10 cm (4 in).
Yak-52M: Refurbishment project for Russian paramilitary flying training fleet of ROSTO (formerly DOSAAF). Prototype shown at Moscow, August 2003. Wing span 9.50 (31 ft 2 in); length 8.025 m (26 ft 4 in), height 2.875 m (9 ft 5¼ in), MT-Propeller as standard, max T-O weight 1,423 kg (3,137 lb), aerobatic weight 1,315 kg (2,899 lb), fuel capacity 230 litres (60.8 US gallons; 50.6 Imp gallons) and range 486 n miles (900 km; 559 miles).
CUSTOMERS: Estimated 1,815 of Iak-52, in 121 production batches, built by 1998, mainly for USSR and Romanian Air Force but latterly also for West European, Australian and American civil markets; Hungarian Air Force received 12 in early months of 1994. Production averaged 10 per year between 1992 and 1996 (almost all to USA or Hungary), augmenting large number of military surplus sales. Twelve delivered to Vietnam in 1997. No known deliveries since 1998.
Iak-52W/TW production began with 122nd batch; total 12 Iak-52Ws (including prototype) built 1999-late 2000; none further by mid-2003; nine to USA; one to Australia. Iak-52TW deliveries began in mid-2001; some 20 built by early 2003; at least 16 to USA and one to Australia.
COSTS: Standard Iak-52 US$165,000; Iak-52W US$130,000; Iak-52TW US$120,000 (all 2002).
DESIGN FEATURES: Tandem-cockpit variant of Yak-50, with unchanged span and length, but with semi-retractable landing gear to reduce damage in wheels-up landing (mainwheels fully retractable in Iak-52TW). Simple, robust, low-wing design with long landing gear legs to accommodate large propeller. Moderately tapered wings and tailplane; curved fin; 'glasshouse' canopy. Current production aircraft lack wingtip fairings. Strengthened wingtips on Iak-52W for optional fitment of tip-tanks. Increased wing span in Iak-52TW.
Wing section Clark YH; thickness/chord ratio 14.5 per cent at root, 9 per cent at tip. Dihedral 2° from root; incidence 2°. Tailplane 0° dihedral, 1°30' incidence.
FLYING CONTROLS: Conventional and manual. Actuation of mass-balanced slotted ailerons by pushrods; mass-balanced elevators by pushrods/cables; and horn-balanced rudder by cables; manually operated trim tab in port elevator; ground-adjustable tab on rudder and each aileron. Pneumatically actuated trailing-edge split flaps.
STRUCTURE: All-metal except for fabric-covered primary control surfaces (these also metal-skinned on Iak-52W/TW). Single-spar wings; modified spar, post-1986 (and some retrofits), permits higher load factors. Iak-52W wingtips strengthened to carry optional tip-tanks. Airframe life 5,000 hours.
LANDING GEAR: Semi-retractable tricycle type, with single wheel and oleo-pneumatic shock-absorber on each unit. Iak-52TW mainwheels (size 6.00-6) fully retractable, on Aerostar pneumatically actuated legs, retracting inward; flush doors. Cleveland wheels and Western tyres on Iak-52W/TW; Scott steerable tailwheel, with 10x3.50-4 tyre, on TW. Pneumatic actuation, nosewheel retracting rearward, main units forward. All three wheels remain fully exposed to airflow, against undersurface of fuselage and wings respectively, to offer greater safety in event of wheels-up emergency landing. Pneumatic drum (hydraulic disc on Iak-52W and TW) mainwheel brakes, operated differentially from rudder pedals. Non-retractable plastics-coated duralumin skis, with shock-struts, can be fitted in place of wheels for winter operations.
POWER PLANT: One 265 kW (355 hp) Aerostar-built VOKBM (Bakanov) M-14P nine-cylinder air-cooled radial, driving a V-530TA-D35 two-blade constant-speed wooden propeller (three-blade MT-Propeller MTV-9-B-C/CL250-27 on Iak-52W and TW). Iak-52TW has 298 kW (400 hp) M-14P-XDK. Two aluminium alloy fuel tanks, in wingroots forward of spar; collector tank in fuselage supplies engine during inverted flight.
Total internal fuel capacity (standard Iak-52) 122 litres (32.2 US gallons; 26.8 Imp gallons). Additional integral tank in each wing of Iak-52W and TW, raising capacity to 280 litres (74.0 US gallons; 61.6 Imp gallons). Oil capacity 10 litres (2.6 US gallons; 2.2 Imp gallons). Provision on Iak-52W/TW for wingtip tanks.
ACCOMMODATION: Tandem seats for pupil (at front) and instructor under long 'glasshouse' canopy, with separate rearward-sliding hood over each seat. Hooker Harness seat belts for both occupants. Dual controls standard. Seats and rudder pedals adjustable. Heating and ventilation standard. Optional 0.20 m³ (7.06 cu ft) baggage compartment in standard version, accessible from rear seat; Iak-52W and TW have externally accessible baggage and battery compartments on port side, aft of rear cockpit, plus permanently mounted retractable ladder for cockpit access.
SYSTEMS: Independent main and emergency pneumatic system, pressure 50 bar (725 lb/sq in), for flap and landing gear actuation, engine starting and brake control. Electrical system (27 V DC) supplied by 3 kW engine-driven generator and (in port wing) 12 V 23 Ah ASAM battery (two 27 V in Iak-52W); two static inverters in fuselage for 36 V AC power at 400 Hz. Oxygen system available optionally.
AVIONICS: Comms: Balkan 5 VHF radio and SPU-9 intercom in standard Iak-52; replaced in Iak-52W/TW by Western instruments including Garmin IC-AQ200 com radio and GTX transponder, AmeriKing ELT and altitude encoder, and NAT AA80-20 intercom.
Flight: ARK-15M automatic radio compass, eight-channel ADF and GMK-1A gyrocompass.
Other avionics available at customer's option.
EQUIPMENT: Strobe and navigation lights, recessed landing and taxying lights on Iak-52W and TW; roll bar in Iak-52TW.