N500BD – BD5 Prototype – Oshkosh EAA Museum

[Benjamin Morgan]

Model: BD-5  Prototype
Year: 1971
Serial number: BD-001
Registration: N500BD
Aircraft first registered: 1971
Status:  Museum Exhibit – EAA Aviation Museum, Oshkosh WI

The prototype, N500BD, flew briefly on September 12, 1971, powered by a 36 hp (27 kW; 36 PS) Polaris Snowmobile engine. This was sixteen months after deposits had been taken, which led to some griping in the press.

The stability of the aircraft with the original V-tail was marginal at best and clearly needed a redesign. With the original fibreglass fuselage, this was a time-consuming process, so the decision was made to switch to an all-metal fuselage with the components incorporating compound curves produced using hyrdoformed aircraft-grade aluminum alloy. These could be modified with relative ease during the testing cycle. It also made economic sense as the orders rolled in, the $30,000 in tooling would be spread over what was now a large order book.

By December 1971, the tooling for the new fuselage was in development. The aircraft now featured a longer, more pointed nose, whereas the N500BD had been patterned on the ASW 15 and had a more rounded, egg-like shaping at the front. While this work was in progress, Bede continued to experiment with modifications to the empennage, eventually abandoning the V-tail for a more conventional rudder and horizontal stabilizer layout with highly swept surfaces. Further testing on N500BD showed flow interference between the horizontal surfaces and the propeller, and the stabilizer was raised six inches to correct it, placing it about midway up the rear fuselage.

[Benjamin Morgan]

Colour photographs of N500BD BD5 prototype:

[Benjamin Morgan]

Photographs of N500BD with the V-Tail replaced with a conventional vertical fin and horizontal tailplane with elevators:

 

[Benjamin Morgan]

Photographs of N500BD on exhibit at the EAA Aviation Museum, Oshkosh WI:

 

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