The Air Sylphe 447 was designed to comply with the U.S. FAR 103 Ultralight Vehicles rules, including the category's maximum empty weight of 115 kg (254 lb). The aircraft has a standard empty weight of 88 kg (194 lb). It features a 35 m2 (380 sq ft) parachute-style wing, single-place accommodation, tricycle landing gear and a single 40 hp (30 kW) Rotax 447 engine in pusher configuration. The 50 hp (37 kW) Rotax 503 engine was a factory option.[1]
The aircraft carriage is built from metal tubing with a ducted fan derived from an industrial air ventilation system. The main landing gear incorporates spring rod suspension.[1]
The aircraft has an empty weight of 88 kg (194 lb) and a gross weight of 210 kg (463 lb), giving a useful load of 122 kg (269 lb). With full fuel of 18 litres (4.0 imp gal; 4.8 US gal) the payload for crew and baggage is 109 kg (240 lb). A version with a gross weight of 310 kg (683 lb) to accommodate heavier pilots was also built.[1]