Viper Aircraft Viperfan

The Viper Aircraft Viperfan was an American homebuilt aircraft that was designed and produced by Viper Aircraft of Kennewick, Washington, introduced in the late 1990s. It was intended to be supplied as a kit for amateur construction, but only one was ever built.

Design and development
The Viperfan was designed to resemble a military jet trainer, but powered by a pusher piston engine. It featured a cantilever low-wing, a two-seats-in-tandem enclosed cockpit under a bubble canopy, retractable tricycle landing gear and a single engine in pusher configuration.

The aircraft was made from composite materials. Its 24.5 ft span wing-mounted flaps and had a wing area of 85.0 sqft. The cabin width was 31 in. The acceptable power range was 240 to 350 hp and the standard engines envisioned to be used were the 285 to 310 hp Continental IO-520 and TSIO-520, or the 350 hp Continental TSIOL-550 powerplant, driving the tail-mounted propeller through an extension shaft.

The Viperfan had a typical empty weight of 1450 lb and a gross weight of 2500 lb, giving a useful load of 1050 lb. With full fuel of 100 u.s.gal the payload for the pilot, passenger and baggage was 450 lb. The aircraft was fully aerobatic and stressed to +/-6g.

The standard day, sea level, no wind, take off with a 350 hp engine was 1000 ft and the landing roll was 1600 ft.

The manufacturer estimated the construction time from the planned kit to be 2000 hours.

The aircraft was not a success due to problems with vibrations in the engine-to-propeller extension shaft and so the aircraft was converted to turbojet power. Eventually it was completely redesigned to become the Viper Aircraft ViperJet MKII.

Operational history
By 1998 the company reported that one aircraft had been completed and was flying.

In May 2015 no examples were registered in the United States with the Federal Aviation Administration and it is unlikely any exist anymore.