St Croix Aircraft principals Chad and Charles Willie had built several Pietenpol Air Campers starting in 1941. The St Croix version of the Pietenpol Aircamper is longer and heavier than the original design, with slightly more wingspan.
The St Croix Pietenpol Aircamper features a cantilever strut-braced parasol wing, two-seats in individual tandem open cockpits with windshields, fixed conventional landing gear and a single engine in tractor configuration.
The aircraft is made with a wooden structure, with some steel parts and its flying surfaces covered in doped aircraft fabric. Its 29.51NaN1 span wing is supported by cabane struts and lift struts and has a wing area of 148square feet. The cabin width is 24inches. The acceptable power range is 65to and the standard engine used is the 400NaN0 Ford Model A automotive conversion powerplant.
The St Croix Pietenpol Aircamper has a typical empty weight of 650lb and a gross weight of 1100lb, giving a useful load of 450lb. With full fuel of the payload for the pilot, passenger and baggage is 378lb. The standard day, sea level, no wind, take off and landing roll with a 400NaN0 engine is 7500NaN0. The designer estimated the construction time from the supplied partial kit and plans as 1000 hours.
The design was later further developed into a biplane, by adding lower wings to the parasol Aircamper, resulting in the St Croix Pietenpol Aerial.