TYPE: Two-seat jet sportplane kitbuilt.

PROGRAMME: Development began in 1988; engineering by AirBoss Aerospace; tooling began in 1996; prototype was initially designed around a Teledyne Continental TSIO-520 and named ViperFan; in early 1999 a switch to jet propulsion was revealed and aircraft renamed ViperJet; development of ViperFan will continue as a lower priority. Prototype (N520VF), officially registered as Hanchette (ViperJet) first flown 22 October 1999 and displayed publicly at Oshkosh in July 2000; underwent further modifications; seriously damaged in crash at St George, Utah, on 13 March 2002, but expected to return to flying in early 2004.

CURRENT VERSIONS: ViperFan: Initial piston-engined version.
ViperJet: Jet-powered prototype.
ViperJet Mk II: Production version, as described.

CUSTOMERS: Ten sold and one flown by end 2003; three customer aircraft then under construction.

COSTS: Kit US$158,400; engine extra. Pressurisation upgrade US$39,000; builder-assistance programme US$75,000 (2003).

DESIGN FEATURES: High-performance personal jet at self-build price. Low wing with sweptback leading-edge and initially with winglets; sweptback tail surfaces with fin fillet and ventral strakes.
Wing aerofoil section NACA 65-218 at root, NACA 65-212 at tip; horizontal tail NACA 66-012; vertical tail NACA 63-015.
Quoted build time 2,000 hours using builder-assistance programme.

FLYING CONTROLS: Conventional and manual. Electric double-slotted flaps, span 1.65 m (5 ft 5 in) deflecting between 0 and 40°; aileron span 1.22 m (4 ft 0 in), deflection 27° up and 18° down; rudder deflection ±25°; elevator deflection ±30°. Dual controls.

STRUCTURE: Extensive use of composites; much of this provided by Unlimited Composites of Scappoose, Oregon. Preformed skins and wing spars.

LANDING GEAR: Retractable tricycle type; nosewheel retracts rearwards, mainwheels inwards. Production aircraft will not have landing gear doors.

POWER PLANT: Prototype initially powered by one refurbished Turbomeca Marboré 2 turbojet rated at 3.91 kN (880 lb st); later changed to converted General Electric T58-8F rated at 4.44 kN (1,000 lb st). Other engine options include versions of Marboré up to 4.89 kN (1,100 lb st). Also recommended is 13.12 kN (2,950 lb st) General Electric J85/CJ-610. Fuel capacity 511 litres (135 US gallons; 112 Imp gallons) in prototype; 1,136 litres (300 US gallons; 250 Imp gallons).

ACCOMMODATION: Pilot and passenger in tandem in unpressurised cockpit; cockpit pressurisation upgrade is available.