First flown in March 1994. Designed by Jim D. Stewart, the Stewart S-51D is an all aluminum 2-place scale reproduction of the North American P-51D Mustang. The kit is prefabricated and held together with pop rivets for shipping. Flush aircraft rivets are installed by the builder. A fast build kit was available for US$89,000, ans the basic kit for US$64,000. The kit is included on the FAA 51 % rule list.

The aircraft features dual controls and is fully aerobatic. The S-51D utilizes liquid cooled engines ranging from 300 to 700 hp. The 91” diameter, constant speed four-blade Hartzell propeller is driven through spur gear reduction with a 0.469 (2.13:1) ratio. Using a 400 hp engine, the S-51D duplicates P- 51 performance, except for top speed.

By 1998, 72 kits had been sold in the previous three years, with two finished.

Engine: V8, 400 hp
HP range: 300-600
Height: 9 ft
Length: 22.25 ft
Wing span: 26 ft
Wing area: 123 sq.ft
Fuel cap: 70 USG
Weight empty: 2200 lb
Gross: 3000 lb
Vne: 273 mph
Speed max: 265 mph
Cruise: 240 mph
Range: 700 sm
Stall: 70 mph
ROC: 2700 fpm
Take-off dist: 900 ft
Landing dist: 1300 ft
Service ceiling: 24,000 ft
Seats: 2
Landing gear: retractable tail wheel

Engine: V8
Wing span: 7.92 m
Wing area: 11.32 sq.m
MAUW: 1360 kg
Empty weight: 998 kg
Fuel capacity: 265 lt
Max speed: 426 kph
Cruise speed: 386 kph
Minimum speed: 113 kph
Climb rate: 13 m/s
Seats: 2
Kit price (1998): $64,000