|Role||Airship for heavy lifting|
|Manufacturer||AeroLift, Blimp Avenue, Tillamook, Oregon|
|First flight||(manned) 23 October 1984|
The AeroLift CycloCrane was a unique US hybrid airship which adopted helicopter derived airfoil control for low speed flight manoeuvring by spinning on its axis. It was intended to be a heavy load lifter, initially aimed at the Canadian logging industry. A proof of concept vehicle flew at times during the 1980s, but no large production aircraft were built.
Design and development
AeroLift Inc was set up in 1980 by CycloCrane inventor Arthur Crimmins, with funding from five major Canadian logging companies, with the objective of building an aircraft capable of the heavy lifting of felled timber from remote sites. Their proposal was to use an airship with a novel drive and control system not based on the usual method involving numerous external, tiltable engines. The Aerolift CycloCrane was a most unusual aircraft, probably unique in combining a lighter than air main lift source, or aerostat, with helicopter and fixed wing methods to provide three dimensional drive and attitude control.
Two proof of concept versions were built, different in size and detail but using the same layout. Each had a conventional, streamlined semi-rigid helium gas bag or aerostat to provide most of the lift needed to support the aircraft and its load. The aerostat contained a rigid internal axle along its long axis, upon which it could rotate. Halfway along the axle, two long beams were fixed at right angles to it and to each other, passing through the envelope where they carried four narrow wings of symmetric airfoil section, or blades as AeroLift termed them. Each blade carried at its tip another, shorter, wing mounted with its long axis perpendicular to the plane of the blade, making a shallow T shape. The blades could be rotated and in normal forward flight their surfaces were nearly parallel to the aerostat's longitudinal axis, both blades and wings providing lift in the conventional way. This lift balanced the difference between gross weight and buoyancy, typically about half the load weight. At the end of the blades, above the wing, were pylons that carried propeller driving engines, oriented at right angles to both wing and blade long axes, so they powered the aircraft forward in normal flight.
At low speeds, for example when manoeuvring to pick up a load, these T shaped aerofoils were rotated though about 90° so the blades were perpendicular to the normal flight direction and the engines pointed around the circumference. They caused the aerostat and its aerofoils to rotate about its axis, clockwise as seen from the rear. In this condition, at rotational speeds of about 13 rpm, changes in the angles of attack (pitch) of the blades and of the wings could provide changes of orientation and velocity. Collective changes of the pitch of the blades moved the aircraft forwards or back; cyclic changes controlled both pitch and yaw. Cyclic changes of the angles of attack of the wings moved the aircraft up and down and from side to side. This wing motion also provided lift to balance any difference in weight and buoyancy when the CycloCrane was not in the forward flight mode.
Extensions of the central axle, forward and aft, provided anchorage points for cables supporting the pilot's cabin and any load connected to it. These cables had to clear the rotating blades and wings, setting the overall length and the depth of the cabin below the axle. The front axle extension also carried a control equipment housing and the longer extension at the rear carried a stabilising tail.
The first version of the CycloCrane was 138 ft (42 m) long, had four piston engines and was fitted with a large, inverted Y shaped tail, chiefly to stabilise it at its moorings by keeping it pointed into wind. It was completed in 1982 but was destroyed that year at its moorings in a storm. It was rebuilt by 1984, a longer aircraft at 178 ft (54.25 m) overall and fitted with an almost circular, 18 faceted, ring shaped tail wire braced to the central axis. Its aerostat was 68 ft 0 in (20.73 m) in diameter and 136 ft 0 in (41.45 m) long. Partly to save weight, this version had only two engines, a pair of 150 hp (112 kW) Textron Lycoming AEIO-320 horizontally opposed piston engines driving 4-bladed propellers. This left the CycloCrane rather underpowered, particularly in lift.
The revised CycloCrane began unmanned flights in August 1984 and made its first manned flight on 23 October 1984. By mid-1985 it had accumulated 7 hrs of flight under a US Forest Service contract, but the lack of power limited the spin rate to 10 rpm, rather than the designed 13 rpm so that the aircraft was less nimble in its movements than intended and also only able to lift loads of about half of the target 2 tons. AeroLift received several military contracts in the late 1980s to keep the CycoCrane idea afloat, particularly one from DARPA in 1988 for mooring investigations on a 36 ft model and renewal of the proof of concept aircraft for military suitability tests. For its final flights the tail was altered again into a combination of the early inverted Y within the ring of the first rebuild.
When the defence funding ended in 1990, the company ceased to trade.
Specifications (proof of concept vehicle, second version)
Data from Jane's All the World's Aircraft 1989/90 p.671
- Length: 178 ft 0 in (54.25 m) overall
- Height: 255 ft 0 in (77.72 m) overall, from hook to uppermost engine
- Volume: 330,000 cu ft (9,300 m3) helium volume, notional
- Empty weight: 1,500 lb (680 kg) helium filled buoyant weight
- Powerplant: 2 × Textron Lycoming AEIO-320 4-cylinder horizontally opposed air cooled piston engines, 150 hp (110 kW) each
- Propellers: 4-bladed
Video about the CycloCrane: http://www.youtube.com/watch?v=cWLhH3wsxUo
- Related development
- Taylor, John W R (1989). Jane's All the World's Aircraft 1989-90. Coulsdon: Jane's Information Group, Ltd. pp. 670–1. ISBN 0-7106-0896-9.
- Kocivar, Ben (September 1985). "Whirling airship". Popular Science 227 (3): 96–7. Retrieved 2010-10-02.
- "CycloCrane video". Retrieved 2010-10-02.
- Lambert, Mark (1991). Jane's All the World's Aircraft 1989-90. Coulsdon: Jane's Information Group, Ltd. p. 652. ISBN 0-7106-0965-5.