Stewart S-51D Mustang

The Stewart S-51D Mustang is an American aerobatic homebuilt aircraft that was designed by Jim Stewart and produced by Stewart 51 of Vero Beach, Florida, introduced in 1994. When it was available the aircraft was supplied as a kit for amateur construction.

The S-51D is a 70% scale version of the World War II P-51D Mustang fighter aircraft.

Design and development
Designer Jim Stewart took a leave of absence from his employer, Pratt & Whitney, in 1989 to work on the S-51D's tooling and design. The prototype took flight on 30 March 1994 and by late June had completed its 40 hours of test flying.

The S-51D Mustang features a cantilever low-wing, a two-seats-in-tandem enclosed cockpit under a bubble canopy, retractable conventional landing gear, and a single engine in tractor configuration.

The aircraft is made from sheet aluminum. Its 26.00 ft span wing mounts flaps and has a wing area of 123.0 sqft. The cabin width is 21 in. The acceptable power range is 300 to 600 hp. The specified propeller is a 91 in diameter, constant speed four-bladed Hartzell Propeller unit, that is driven by a spur gear with a (2.13:1) reduction ratio.

The S-51D Mustang has a typical empty weight of 2200 lb and a gross weight of 3000 lb, giving a useful load of 800 lb. With full fuel of 70 u.s.gal the payload for the pilot, passenger, and baggage is 380 lb.

The standard day, sea level, no wind, take off with a 400 hp engine is 1080 ft and the landing roll is 1800 ft.

The manufacturer estimated the construction time from the supplied standard kit as 2000 hours. A fast-build kit was also available.

Operational history
By 1998 the company reported that 72 kits had been sold and two aircraft were completed and flying.

In March 2014, 12 examples were registered in the United States with the Federal Aviation Administration, although a total of 19 had been registered at one time.