The BD-4 is a light general aviation aircraft marketed in the United States for homebuilding since 1968. It was the first home-built aircraft to be offered in kit form, and remains one of the world’s most popular home-builds with thousands of plans issued and hundreds of versions completed.

Jim Bede designed the BD-4, the first real “kitplane” in the world. The design was based on a high-wing cantilever monoplane of conventional design, able to be fitted either with tailwheel or tricycle undercarriage, as the builder chooses. The builder was also able to choose between building a two-seat or four-seat version. Bede wrote a 165-page BD-4 builder’s book, “Build Your Own Airplane”, that is still available today, that gives the amateur builder a good perspective on construction techniques.

The intention was to have people with little or no fabrication experience start with a set of comprehensive plans and work up to a “bolt together” operation, using complex components provided from the factory. In order to simplify construction, there were few curved surfaces and most of the fuselage was made up of flat aluminum sheeting. The only major components with compound curves were the engine cowling and landing gear spats, which were made of fiberglass. The fuselage is constructed of aluminum angle braces, bolted together to form a truss frame.
An innovative wing structure employed a “panel-rib” constructed in sections consisting of a rib whose upper edge was extended horizontally to become one section of the wing surface. The wing was progressively built up by sliding these sections together over the tubular spar and fastening them together where they met. Although the original wing design was easy to build, the current BD-4B features a redesigned, more conventional, metal wing with a tubular spar bonded to honeycomb ribs. There are two seat and four seat models with 1,250 lb (567 kg) empty weight and 2,400 lb (1,089 kg) gross weight. Estimated construction time is 900 hours. 700 were completed and flown by 2011.

General characteristics

Crew: one pilot
Capacity: 3 passengers
Length: 21 ft 5 in (6.53 m)
Wingspan: 25 ft 7 in (7.8 m)
Height: 7 ft 3 in (2.21 m)
Empty weight: 990 lb (450 kg)
Gross weight: 2,000 lb (910 kg)
Powerplant: 1 × Lycoming O-320, 150 hp (112 kW)


Maximum speed: 234 mph (377 km/h)
Range: 900 miles (1,450 km)
Rate of climb: 1,250 ft/min (6.4 m/s)