TYPE: Four-seat light business aircraft.

PROGRAMME: Design began January 1981; mockup completed early 1982, detail design and construction of prototype by Designability Ltd of Dilton Marsh, Wiltshire, began July 1982 under CMC contract; first flight of prototype (G-BKRL) 12 December 1988 at RAE Bedford; by September 1990 had made 40 flights investigating basic handling qualities at speeds up to 200 knots (371 km/h; 230 mph) IAS; new tailplane incorporating TKS liquid anti-icing system subsequenty installed on prototype prior to resumption of flight testing aimed at expanding airspeed, altitude and CG envelopes.
Design of second prototype began April 1989; Slingsby Aviation to manufacture fuselage and wings in collaboration with Designability, both under CMC contract; expected to be completed September 1991, featuring reprofiled nose for EFIS avionics, substitution of oleo-pneumatic main landing gear legs for current rubber-in-compression units, and powered by demonstration versions of Noel Penny NPT 754 turbofans.

DESIGN FEATURES: Streamline composites airframe; sweptback supercritical technology wings; sweptback tail unit; twin low-cost turbofans; pressurised and air-conditioned cabin; TKS liquid de-icing and decontamination system on wing and tailplane leading-edges of production aircraft (see Programme); warm air de-icing of engine intake leading-edges. First prototype has lower-powered engines; lacks full pressurisation/air-conditioning system, advanced avionics and instrumentation of planned production model.
ARA designed wing section and 3D profiles combining laminar flow and supercritical technology; thickness/chord ratio 14 per cent at root, 11 per cent at tip; wing sweepback at quarter-chord 25°.

FLYING CONTROLS: All-moving fin; two independent tailplane sections operated collectively for pitch control and differentially for roll control; geared anti-servo tabs in fin and tailplane sections, adjustable for trim; no ailerons. Full-span electrically actuated trailing-edge plain flaps, with ± 45° deflections for high drag landing and airbraking/lift dumping; no spoilers.

STRUCTURE: Two-spar wings, primarily of GFRP, with some carbonfibre reinforcement; carbonfibre flaps; fuselage built in three sections as unpressurised nose housing avionics and nosewheel gear, pressurised cabin (production aircraft), and pressurised rear housing baggage bay, with fuel tanks below and equipment bays to rear; fuselage primarily GFRP with some carbonfibre reinforcement (fore and aft carbon bulkheads, engine and tailplane axle frames moulded in); pressure cabin section divided approximately along aircraft horizontal datum, with upper section formed by electrically actuated upward opening canopy hinged at windscreen leading-edge; bonded-in acrylic side windows carry pressurisation tension; nose opens for access to avionics; composites engine nacelles, with stainless steel firewalls; composites fin and tailplane; fin sternpost projects to bottom of rear fuselage; low-set tailplane in two independent sections, each mounted on steel axle projecting from side of rear fuselage; carbonfibre tabs.

LANDING GEAR: Electrically retractable tricycle type, main units retracting inward into wingroot wells, nosewheels forward. Well closure doors linked mechanically to landing gear units. Gravity extension assisted by bias springs and aerodynamic drag. Long-stroke shock absorber in each unit, using synthetic elastomers in compression. Main units, each with single Cleveland wheel, size 5.00-5, have tyres size 11 x 4, pressure 4.82 bars (70 lb/sq in) on prototype, 11.56 bars (170 lb/sq in) on production aircraft. Unpowered steerable twin-wheel nose unit has wheels size 4.00-3 and tyres size 8.5 x 2.75 in, pressure 2.75 bars (40 lb/sq in) on prototype, 3.8 bars (55 lb/sq in) on production aircraft. Hydraulic disc brakes. Parking brake. New, oleo-pneumatic main landing gear is being designed for production aircraft.

POWER PLANT: Prototype 001 has two Noel Penny Turbines NPT 301-3A turbojets each of nominal 1.33 kN (300 lb st) rating. Production aircraft will have two low-bypass Noel Penny Turbines NPT 754 turbofans, each of 3.78 kN (850 lb st). Each engine in nacelle, mounted on crossbeam located in rear fuselage. Fuel tanks in fuselage, below baggage bay. Prototype has total fuel capacity of 455 litres (120 US gallons; 100 Imp gallons). Production aircraft will have maximum capacity of 591 litres (156 US gallons; 130 Imp gallons). Refuelling point on upper surface of fuselage.

ACCOMMODATION: Cabin seats four, in two pairs, on semi-reclining (35°) seats beneath upward opening jettisonable canopy. Options include dual controls, and accommodation for pilot, stretcher and attendant in medevac role. Unpressurised baggage bay aft of cabin, capacity 54 kg (120 lb), with external door in upper surface of fuselage.

SYSTEMS (production aircraft): Air-conditioning and pressurisation (max differential 0.66 bar; 9.6 lb/sq in) by engine bleed air, with simple Normalair-Garrett air cycle cold air/dehumidifier unit. Electrical system powered by dual engine driven 3kVA starter/generators. Hydraulic system for brakes only.

AVIONICS (production aircraft): Full nav/com and storm-avoidance systems. Bendix/King avionics, mounted in nose bay, supply EADI and EHSI information to two CRTs in pilot's instrument panel, together with weather radar. CRT displays can be transferred in the failure mode. Reduced scale electro-mechanical standby flight instruments. All avionics systems fully integrated with digital autopilot.