TYPE: Twin-turboprop light transport
COUNTRY OF ORIGIN: China
Chinese name: Yunshuji-12 (Transport aircraft 12)
Export marketing name: Twin Panda
PROGRAMME: Initiated as uprated version of Y-12 (I); first flight 16 August 1984. Y-12 (IV) (B-569L, first flight 30 August 1993) received production approval September 1995.
CURRENT VERSIONS: Y-12 (I): Initial version (first flight 14 July 1982), with PT6A-11 engines; three prototypes and approximately 30 production examples built.
Y-12 (II): Major production version; higher-rated engines, no leading-edge slats and smaller ventral fin. Certified by CAAC 25 December 1985 and UK CAA (BCAR Section K) 20 June 1990.
Detailed description applies to Y-12 (II) except where indicated.
Y-12 (IV): Improved version with sweptback wingtips; modifications to control surface actuation, main gear and brakes; redesigned seating for 18 to 19 passengers; starboard side rear baggage door; maximum payload and maximum T-O weight increased. Further changes include Rockwell Collins or Honeywell com/nav for both VFR and IFR, plus optional colour weather radar. GPS, Omega navigation, wing and tail de-icing, and oxygen system. Domestic certification received 3 July 1994 and FAR Pt 23 approval on 26 March 1995; Indonesian certification 16 November 2000. Sichuan Airlines order for 20 (7 November 2000) assumed to be of this version.
Twin Panda: Abortive 1998-99 attempt for version of Y-12 (IV) to be completed and marketed by Canadian Aerospace Group.
Y-12E: Next-generation version for Chinese market, with 559 kW (750 shp) PT6A-135A engines (derated to 462 kW; 620 shp) with Hartzell four-blade lightweight propellers, strengthened structure, reduced noise levels and improved avionics. Announced at Airshow China, November 2000; passed CAAC preliminary design review 16 November 2000. First flight August 2001; award of CAAC type certificate announced 26 February 2002; launch customer Sichuan Airlines (option for 10).
Y-12F: Concept study for version with pressurised fuselage and retractable landing gear.
Y-12G: In design stage 2002-03 as dedicated cargo version with large side door and capacity for three LD3 containers.
CUSTOMERS: Over 110 built by Harbin by mid-2001. Venezuela considering purchase of 10 in late 2001.
COSTS: Batch of 15 PT6-engined aircraft valued at US$58 million (1999).
DESIGN FEATURES: Designed to standards of FAR Pts 23 and 135 Appendix A and developed to improve upon modest payload/range of piston-engined Y-11. Constant-chord high braced wings, with small stub-wings at cabin floor level supporting mainwheel units; basically rectangular-section fuselage, upswept at rear; non-swept tail surfaces; large dorsal fin; ventral fin under tailcone.
Wing section LS(1)-0417; thickness/chord ratio 17 per cent; dihedral 1° 41'; incidence 4°.
FLYING CONTROLS: Conventional and manual. Drooping ailerons, horn-balanced elevators and rudder; trim tab in starboard aileron, rudder and each elevator: electrically actuated two-segment double-slotted flaps on each wing trailing-edge.
STRUCTURE: Conventional all-metal structure with two-spar fail-safe wings and stressed skin fuselage; Ziqiang-2 resin bonding on 70 per cent of wing structure and 40 per cent of fuseiage; integral fuel tankage in wing spar box; bracing strut from each stub-wing out to approximately one-third span.
LANDING GEAR: Non-retractable tricycle type, with oleo-pneumatic shock-absorber in each unit. Single-wheel main units, attached to underside of stub-wings. Single non-steerable nosewheel. Mainwheel tyres size 640x230, pressure 5.50 bar (80 lb/sq in); nosewheel tyre size 480x200, pressure 3.50 bar (51 lb/sq in). Hydraulic brakes. Minimum ground turning radius 16.75 m (54 ft 111/2 in).
POWER PLANT: Two Pratt & Whitney Canada PT6A-27 turboprops, each derated to 462 kW (620 shp) and driving a Hartzell HC-B3TN-3B/T10173B-3 three-blade constant-speed reversible-pitch propeller. All fuel in tanks in wing spar box, total capacity 1,616 litres (427 US gallons; 355.5 Imp gallons), with overwing gravity filling point each side. No recent news of domestic WJ9 turboprop (442 to 520 kW; 593 to 697 shp). said to have been under development for Y-12 and other aircraft.
ACCOMMODATION: Crew of two on flight deck, with access via forward-opening door on port side. Four-way adjustable crew seats. Dual controls. Main cabin can accommodate up to 17 passengers in commuter configuration, in three-abreast layout (with aisle), at seat pitch of 75 cm (30 in). Alternative layouts for up to 15 parachutists, or all-cargo configuration with 11 tiedown rings. Passenger/cargo double door on port side at rear, rear half of which opens outward and forward half inward; foldout steps in passenger entrance. Emergency exit on each side at front of cabin and opposite passenger door on starboard side at rear. Baggage compartment in nose and at rear of passenger cabin, for 100 kg (220 lb) and 260 kg (573 lb) respectively.
SYSTEMS: Hamilton Sundstrand R70-3WG environmental control system. Hydraulic system (operating pressure 118 to 147 bar; 1,711 to 2,132 lb/sq in) for mainwheel brakes. Two 6 kW DC starter/generators, two 600 VA 400 Hz single-phase static inverters and one 43 Ah Ni/Cd battery for electrical power. Goodrich Type 29S-7D 5178 anti-icing system optional for wing, tailplane and fin leading-edges. Oxygen system optional.
AVIONICS: Comms: VHF-251 and HF-230 radio, AUD-251A intercom and TDR-950 transponder.
Radar: Honeywell 1400C, RDS-81 or RDS-82 weather radar optional.
Flight: ALT-50 radio altimeter, DME-451, ADF-650A, MKR-350 marker beacon receiver, KLN90 GPS receiver, VIR-351 VOR, GLS-350 glideslope receiver and PN-101 pictorial navigation display. Doppler navigation with satellite responder (Y-12 (IV). Omega nav) optional (for example, in mineral detection role).
Instrumentation: 20025-11324 airspeed indicator, 510-8D10 horizon, 101420-11934 encoding altimeter, 30230-11101 vertical speed indicator, 9551-BN541 bank indicator, LC-2 magnetic compass, ZWH-1 outside air temperature indicator, and ZEY-1 flap position indicator; dual engine torquemeters, interturbine temperature indicators, gas generator tachometers, oil temperature and pressure indicators, fuel pressure and quantity indicators; 309W clock; and XDH-10B warning light box.
EQUIPMENT: Hopper for 1,200 litres (317 US gallons; 264 Imp gallons) of dry or liquid chemical in agricultural version. Appropriate specialised equipment for firefighting, geophysical survey (for example, long, kinked sensor tailboom) and other missions.