The Bede 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. It remains one of the world's most popular homebuilts with thousands of plans issued and hundreds of versions completed to date.
Design and development
Based on previous work with innovative light aircraft, the BD-1 (eventually developed into the American Aviation AA-1 Yankee) and BD-2, 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 provided a 165-page BD-4 builder's book, "Build Your Own Airplane" (still supplied today) that gave even the tyro 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, with 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. 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 circular spar and fastening them together where they met. Although the original wing design was easy to build, current (2007) BD-4s feature a redesigned, more conventional, metal wing.
The BD-4 first appeared at the 1968 EAA Rockford, Illinois air show (which moved to Oshkosh, Wisconsin in 1970). Based on early reports in the trade press, it immediately became a "hit." Like the BD-1, the built-up BD-4s offered excellent performance; using the same 108 hp Lycoming O-235 as the Cessna 152 it could reach 130 knots, besting the 152 by about 20 knots. Even higher power could be accommodated with engines up to 220 hp although 130-150 knots (240-280 km/h) was typical.
The BD-4 aircraft has proven to be very strong, and has an excellent safety record; but probably its greatest legacy is that it helped start the homebuilding craze for thousands of enthusiasts. Other kit plane manufacturers studiously copied the Bede Aircraft techniques and his customer service model for their own products, enabling countless aviation enthusiasts to find an affordable means to fly their own aircraft.
The longevity of BD-4 design has been exemplified by the modern versions, crammed with high-tech instrumentation and electronics, that do not look out of place beside any contemporary light plane.
Specifications (typical 2007 BD-4B, 4 seats)
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)