Bede BD-4

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BD-4
Raffensparger BD-4 (N643R).jpg
BD-4
Role Recreational/Utility aircraft
Manufacturer Bedecorp for homebuilding
Designer Jim Bede
First flight 1968
Introduction 1968
Developed from BD-1
Front view of a BD-4 taildragger.
Rear view of a BD-4 taildragger

The Bede BD-4 is a light general aviation aircraft marketed in the United States for homebuilding since 1968. It was the first homebuilt aircraft to be offered in kit form.[1] 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[edit]

Tubular spar of a BD-4C

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 wrote a 165-page BD-4 builder's book, "Build Your Own Airplane", that is still available in 2012, that gives the amateur builder a good perspective on construction techniques.[2]

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. The fuselage is constructed of aluminum angle braces bolted together to form a truss frame.[3]

An innovative feature was the wing structure, which 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.[4]

One downside to the panel-rib construction was not noticed until the aircraft had been in service for some time. Because the panels were glued together, they formed a liquid-tight bond, unlike conventional systems using rivets. Instead of using a separate tank to hold fuel, builders simply drilled holes in the ribs to interconnect the sections to form a tank. In service, it was found that leaks inevitably developed due to problems like improper seals and natural flexing of the wing.[5] BedeCorp later redesigned the wing to use a more conventional system with separate fuel tanks in the BD-4C.[6]


Variants[edit]

BD-4B
Two-seat or four-seat model with 1,250 lb (567 kg) empty weight and 2,400 lb (1,089 kg) gross weight. Estimated construction time is 900 hours. 700 completed and flown by 2011.[7]
BD-4C
Improved four-seat model with 1,200 lb (544 kg) empty weight and 2,400 lb (1,089 kg) gross weight. Estimated construction time is 700 hours. Two completed and flown by 2011.[7]

Specifications (BD-4B)[edit]

Data from Kitplanes and The Incomplete Guide to Airfoil Usage[7][8]

General characteristics

Performance

  • Cruise speed: 198 mph (319 km/h; 172 kn)
  • Stall speed: 61 mph (98 km/h; 53 kn)
  • Range: 900 mi (782 nmi; 1,448 km)
  • Rate of climb: 1,700 ft/min (8.6 m/s)

References[edit]

  1. ^ The TEAM Aviation BD-4
  2. ^ "Books | Bedecorp, LLC". Bedecorp.com. Archived from the original on 2013-09-17. Retrieved 2012-10-20. 
  3. ^ "What kind of airplane should you build?". Air Progress: 41. Winter 1971. 
  4. ^ Bayerl, Robby; Martin Berkemeier; et al: World Directory of Leisure Aviation 2011-12, page 97. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X
  5. ^ Mellema, Roger (March 1986). "Fuel Tanks". BD-4 Builders/Owners Newsletter. 
  6. ^ "BD-4C". BedeCorp. 
  7. ^ a b c Vandermeullen, Richard: 2012 Kit Aircraft Buyer's Guide, Kitplanes, Volume 28, Number 12, December 2011, page 45. Belvoir Publications. ISSN 0891-1851
  8. ^ Lednicer, David (2010). "The Incomplete Guide to Airfoil Usage". Retrieved 15 October 2014. 
  • Taylor, Michael J.H. Jane's Encyclopedia of Aviation. London: Studio Editions, 1989, p. 123. ISBN 0-517-10316-8.
  • Winchester, Jim. "Bede BD-10." Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. Kent, UK: Grange Books plc., 2005. ISBN 978-1-84013-809-2.
  • World Aircraft Information Files (File 890 Sheet 05). London: Bright Star Publishing.

External links[edit]