D-96 | |
---|---|
Role | Hot air airship |
National origin | United Kingdom |
Manufacturer | Cameron Balloons |
First flight | 7 January 1973 |
Number built | 16 by January 1984 |
The Cameron D-96 was the first hot air airship, a powered, steerable lighter-than-air craft carrying two or three crew marrying the elongated envelope of an airship with the externally localized heat source of a modern hot air balloon. It was designed and built in the UK and first flown in 1973.
Cameron Balloons had been producing hot air balloons for five years when they designed the world's first hot air airship or thermal airship. This, the D-96, has much in common with the balloons, being a non-rigid airship, covered in a nylon fabric and with a propane burner to feed hot air into the envelope from a gondola suspended below it. However, it has the elongated body shape of conventional helium and hydrogen filled airships, airscrew propulsion and stabilizing tailfins. With a length to minimum diameter ratio of only about 2.5, the envelope is fatter than that of many airships. The D-96 is powered a 1.6 L Volkswagen engine, modified to run on propane so that engine and burner use the same fuel. Mounted at the rear of the gondola, this drives a large diameter, partly shrouded propeller. This gondola carries propane fuel and a double burner, the pilot and up to two passengers. Hot air is guided into the envelope by a small, funnel-like extension above the burners.
On 4 January 1973 Don Cameron and Teddy Hall demonstrated the first D-96, registration G-BAMK, at the Icicle meeting at Newbury, Berkshire. Some records state that this first flight was made on 7 January or over the weekend of 6–7 January. After some initial testing, Cameron's attention returned to balloon manufacture but interest in the airship was revived in 1976 by an order from the U.S.A. The early flights had revealed some directional stability problems, addressed by progressively increasing the number of tailfins. The instabilities were finally cured by a four-finned, cruciform arrangement, with the fins inflated by air from the propeller slipstream, fed from an intake with a tongue-like scoop through a passage along the keel. A rudder, operated from the gondola by cable, was added to the lower fin. At the same time the gondola suspension was improved so that it no longer distorted the envelope.