As its name implies, the Spirit 103 was designed to comply with the US FAR 103 Ultralight Vehicles rules, including the category's maximum empty weight of 2540NaN0. The aircraft has a standard empty weight of 2050NaN0. It features a parachute-style high-wing, single-place accommodation, tricycle landing gear and originally a single 450NaN0 2si 460 engine in pusher configuration. The 400NaN0 Rotax 447 and 500NaN0 Rotax 503 engines are used on current models.[2]
Early models used a large sized 500square feet parachute, whereas current models use a smaller and faster 400square feet wing.
The aircraft is built from a combination of bolted aluminium and stainless steel tubing. It features a double ring propeller guard that has been roll-over tested. The fuel tank is made from aluminium. In flight steering is accomplished via foot pedals, or optionally a control stick, that actuate the canopy brakes, creating roll and yaw. On the ground the aircraft has lever-controlled nosewheel steering. The main landing gear incorporates gas strut suspension. The aircraft is factory supplied in the form of an assembly kit that requires 30–50 hours to complete.
Originally marketed by the factory under their own name, the aircraft is now marketed under the brand name Blue Heron, although the manufacturer remains the same.