Flight Dynamics Seasprite
This single- or two-seat homebuilt glider is distinguished by an aerofoil-shaped fuselage and bat-like sailwing type wings, the tail unit being carried on an aluminium boom. It is an unpowered Stage 1 version of an aircraft which, in fully developed powered form, will be known as the Flightsail VII, the Seasprite being of more simplified construction, and it is being marketed as plans to amateur constructors.
The fuselage is a framework of aluminium tubing, the sides and top of which are covered with polyethylene foil, except for the upper part of the nose section, which has a transparent covering of polyester film and Plexiglas. Alternatively, the structure can be covered with aluminium foil for only a minimal weight increase, and this has a much longer life. The underside of the fuselage has catamaran-type twin floats, built of plastics with a plywood covering, enabling the Seasprite to be operated off water if so desired.
The wings are of triangular planform with aluminium tube leading edges and wire trailing edges, the whole being covered in polyethylene. They can be folded rearwards when not in use but are otherwise braced to the fuselage sides. The wing tips pivot about their leading edges to provide roll control. The tail is built as a single fin/tailplane unit pivoting only in the vertical plane for control in pitch.
The pilot sits in an open cockpit in the centre section, to the right of the aluminium boom carrying the tail unit, and his weight is balanced by a counterweight at the port wing tip if a second pilot or passenger is not carried.
One Seasprite has been fitted with twin tail booms preparatory to adding a small pusher engine between them, this being an interim stage, as the Seasprite II, in the development of the Flightsail VII.
Wingspan 34 ft 0 in
Length 20 ft 0 in
Height 8 ft 0 in
Wing area: 166.0 sqft
Aspect ratio: 6.96
Empty weight: 165 lb
Max weight: 500 lb
Lift off speed 30 mph
Cruise speed 35 mph
Max aero-tow speed: 35 mph
Best glide ratio: 6:1 at 50 mph