Single-seat twin-engined mid-wing monoplane with conventional three-axis control. Wing has unswept leading and trailing edges, and constant chord; T-tail. Pitch control by fully flying tail; yaw control by fin-mounted rudi-der; roll control by one-third-span ailerons; control inputs through stick for pitch/roll and pedals for yaw. Cantilever wing; wing profile Worthmann FX 63-137; double-surface. Undercarriage has two wheels in tandem with wing-tip skids; steel-spring suspension on tailwheel and oleo-pneumatic suspension on main wheels. Push-right go-right tailwheel steering connected to yaw control. Brake on main wheel. Glass-fibre/Kevlar fuselage, totally enclosed. Engines mounted above wing driving tractor and pusher propellers. Wing and T-tail are also made with carbon and glassfibre, Kevlar and Dacron covered.
A twin-engined push-pull aircraft, the Epervier descends in a direct line from his earlier Libellule. This prototype is a cross-country microlight, capable of covering 522 mile (840km) on one engine at economic cruise. The consumption of the Konig SC340 tri-cylinder is 1.6 US gal/h (1.3 Imp gal/h, 6.0 litre/h) with the Epervier cruising at 40mph (65 kph). The Epervier can also be regarded as a motor glider with a glide ratio of 20/1 at 34 mph (55 kph), thanks to its Worthmann FX63-137 wing profile combined with a NACA0012 profile for the empennage. In addition to the ailerons, this wing is also fitted with three-position flaps acting as flaps at 20 and 15 deg and air brakes at 70 deg camber.
The construction of the prototype, designed at the end of 1981, was first seen during the summer of 1982, the first flight being made in May 1983.