St Croix Sopwith Triplane

The St Croix Sopwith Triplane is an American homebuilt aircraft that was designed and produced by St Croix Aircraft of Corning, Iowa. When it was available the aircraft was supplied as a kit or in the form of plans for amateur construction. The aircraft is a full-size replica of the 1916 Sopwith Triplane fighter aircraft.

Design and development
The aircraft features a cantilever strut-braced triplane layout, a single-seat, with an optional two-seats-in-tandem open cockpit, fixed conventional landing gear and a single engine in tractor configuration.

The St Croix Sopwith Triplane differs from the original 1916 design in that it employs a welded steel tube fuselage, modern engine installation and other minor details. The Triplane is all covered in doped aircraft fabric. Its 26.50 ft span wing uses strut and cable-bracing and has a wing area of 231.0 sqft. The cabin width is 27 in. The acceptable power range is 150 to 250 hp and the standard engine used is the 190 hp Lycoming O-435 powerplant.

The St Croix Sopwith Triplane has a typical empty weight of 1475 lb and a gross weight of 2000 lb, giving a useful load of 525 lb. With full fuel of 35 u.s.gal the payload for the pilot, passengers and baggage is 315 lb.

The standard day, sea level, no wind, take off with a 190 hp engine is 250 ft and the landing roll is 750 ft.

The manufacturer estimated the construction time from the supplied kit as 4000 hours.

Operational history
By 1998 the company reported that 25 kits had been sold and 15 aircraft were completed and flying.