- Role- An experimental "proof-of-concept" VTOL vehicle.
- National origin- Canada.
- Manufacturer- Avro Aircraft Ltd. (Canada).
- Designer- John Frost.
- First flight- 12 November 1959.
- Introduction- 1958.
- Retired- 1961.
- Status- experimental.
- Primary users- United States Air Force (intended) and United States Army (intended).
- Produced- 1958–1959.
- Number built- 2.
- Project cost- $10 million (USD).
The Avro Canada VZ-9 Avrocar was a VTOL aircraft developed by Avro Aircraft Ltd. (Canada) as part of a secret U.S. military project carried out in the early years of the Cold War. The Avrocar intended to exploit the Coandă effect to provide lift and thrust from a single "turborotor" blowing exhaust out the rim of the disk-shaped aircraft to provide anticipated VTOL-like performance. In the air, it would have resembled a flying saucer.
Originally designed as a fighter-like aircraft capable of very high speeds and altitudes, the project was repeatedly scaled back over time and the U.S. Air Force eventually abandoned it. Development was then taken up by the U.S. Army for a tactical combat aircraft requirement, a sort of high-performance helicopter. In flight testing, the Avrocar proved to have unresolved thrust and stability problems that limited it to a degraded, low-performance flight envelope; subsequently, the project was cancelled in September 1961.
Through the history of the program, the project was referred to by a number of different names. Avro referred to the efforts as Project Y, with individual vehicles known as Spade and Omega. Project Y-2 was later funded by the U.S. Air Force, who referred to it as WS-606A, Project 1794 and Project Silver Bug. When the U.S. Army joined the efforts it took on its final name "Avrocar", and the designation "VZ-9", part of the U.S. Army's VTOL projects in the VZ series.
The Avrocar was the ultimate result of a series of blue skies research projects by designer "Jack" Frost, who had joined Avro Canada in June 1947 after working for several British firms. He had been with de Havilland from 1942 and had worked on the de Havilland Hornet, de Havilland Vampire jet fighter and the de Havilland Swallow aircraft, where he had been the chief designer on the supersonic research project.
At Avro Canada, he had worked on the Avro CF-100 before creating a research team known as the "Special Projects Group" (SPG). Frost first surrounded himself with a collection of like-minded "maverick" engineers, then arranged for a work site. Initially ensconced in the "Penthouse", a derisive nickname for the executive wing of the Administration Building, the SPG was subsequently relocated to a Second World War-era structure across from the company headquarters, the Schaeffer Building, that was secured with security guards, locked doors and special pass cards. At times, the SPG also operated out of the Experimental Hangar where it shared space with other esoteric Avro project teams.
At the time, Frost was particularly interested in jet engine design and ways to improve the efficiency of the compressor without sacrificing the simplicity of the turbine engine. He found Frank Whittle's "reverse flow" design too complex and was interested in ways to clean up the layout. This led him to design a new type of engine layout with the flame cans lying directly outside the outer rim of the centrifugal compressor, pointed outwards like the spokes on a wheel. Power for the compressor was drawn from a new type of turbine similar to a centrifugal fan, as opposed to the more typical pinwheel-like design of conventional engines. The turbine drove the compressor using gearing, rather than a shaft. The resulting engine was arranged in the form of a large disk, which he referred to as a "pancake engine." The jet thrust exited from around the entire rim of the engine, and this presented problems trying to adapt the design to a typical aircraft.
The Project Y mock-up in the Experimental Flight Hangar c. 1954. The scalloped nozzles on the near edge direct the jet thrust rearward. The cockpit is just visible at the front of the upper spine.
At the same time, the aircraft industry as a whole was becoming increasingly interested in VTOL aircraft. It was expected that any future European war would start with a nuclear exchange that would destroy most airbases, so aircraft would need to operate from limited airbases, roads or even unprepared fields. Considerable research effort was put into various solutions to securing a second-strike capability. Some of these solutions included rocket-launched aircraft like the zero-length launch concept, while many companies started work on VTOL aircraft as a more appropriate long-term solution. There were several desings over the yaers and some were wind tunnel tested and 1 was even flown.
On 9 June 1961, a second USAF/NASA flight evaluation of the Avrocar was conducted on the similarly modified second prototype at the Avro facility. During these tests, the vehicle reached a maximum speed of 20 knots (37 km/h) and showed the ability to traverse a ditch six feet across and 18 inches (460 mm) deep. Flight above the critical altitude proved dangerous if not nearly impossible due to inherent instability. The flight test report further identified a range of control problems.
Before modifications could be achieved, funding ran out in March 1961. Frost's proposals for a modified design were not accepted, and the Avrocar and related WS-606A supersonic VTOL programs were officially cancelled in December 1961 by the U.S. military. Avro company executives encouraged additional VTOL research projects, exploring new configurations married to a disk platform and even a "lift jet" version, but no further interest resulted from Canadian or other sources, to cap the end of this Special Projects Group program. In 1961, a number of later proposals, including the Avro P470 VTOL fighter concept derived from the Special Projects Group, were submitted to fulfill a NATO competition for a tactical strike fighter. These needs were filled by the Hawker Siddeley Harrier, but in more general terms, interest in VTOL faded as it became widely believed a nuclear first strike would not be used at the start of a European war.
The second Avrocar had logged about 75 flight hours at the end of the flight testing. Judged by its performance, the Avrocar was an abject failure: it couldn't lift itself safely more than a few feet off the ground, and its bulbous design limiting high-speed performance accompanied by unbearable heat and screaming exhaust noise, made it impractical for the military. Although considered a technical failure, its design would be prophetic: it was a rubber skirt shy of being one of the world's first hovercraft, the Saunders Roe SR.N1 also taking off in 1959. Nevertheless, company designer John Frost applied for a number of patents in Canada, the UK and the U.S. that established the pivotal role that the Avrocar and related Avro experimental vehicles made in the VTOL world.
The Avro VZ-9 Avrocar was a "dead end" in VTOL design, according to Russell Lee, curator at the National Air and Space Museum, yet its technological innovations have intrigued other designers. One of the design elements it embodied, the use of ducted fans, led to other experimental programs. Dr. Paul Moller, a Canadian expatriate who had worked at Avro Canada as a young engineer, based an initial series of experimental VTOL vehicles on "saucer" technology utilizing the buried ducted fan à la-Avrocar. The XM-2, the first of the series looked remarkably like a miniature flying saucer. After successful tether tests, the saucer designs also at one time publicized as "discojet" were abandoned and their latest project, the Moller Skycar, has a flying-car appearance.
The Avrocar story did not end with the termination of the program. Only two Avrocars were ever produced and because the U.S. military had paid for the work, they reverted to U.S. ownership at the end of the program. The second example, S/N 59-4975, utilized for "flight" testing, returned to Canada briefly for display in Montreal at the Man and His World Exhibition (1968); after a lengthy period of outdoor display, it is now under restoration at the U.S. Army Transportation Museum in Fort Eustis, Virginia.
Avrocar at the National Museum of the United States Air Force in Dayton, Ohio The first Avrocar, S/N 58-7055 (marked AV-7055), after tethered testing, became the "wind tunnel" test model at NASA Ames, where it remained in storage from 1961 until 1966, when it was donated to the National Air and Space Museum, in Suitland, Maryland. There it continued gathering dust for the next forty years. The Museum finally scheduled it for restoration and display at their newly constructed Steven F. Udvar-Hazy Center. Instead the Avrocar has been loaned to the National Museum of the United States Air Force in Dayton, Ohio, arriving in November, 2007. After a full restoration, which included fabrication of both missing plexiglass bubbles, it was put on display in June 2008 in the Museum's Cold War Gallery. It has since been moved to the Presidential Aircraft Gallery.
A full-scale replica of the Avrocar was prepared for the 2002 production, Avrocar: Saucer Secrets from the Past. It now resides as an exhibit at the Western Canada Aviation Museum, Winnipeg, Manitoba, Canada.
Data from: Avrocar: Canada's Flying Saucer... and The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters.
- Crew: 2.
- Capacity: 1 observer/engineer.
- Diameter: 18 ft (5.5 m).
- Height: 3 ft 6 in (1.07 m).
- Wing area: 254 sq ft (23.6 m2).
- Empty weight: 3,000 lb (1,361 kg).
- Max takeoff weight: 5,560 lb (2,522 kg).
- Powerplant: 3 × Continental J69-T-9 turbojet engines, 660 lbf (2.9 kN) thrust each.
- Service ceiling: 10,000 ft (3,000 m) (designer's boastful estimated), 3 ft (0.91 m) (actual).
- Range: 995 mi (865 nmi; 1,601 km) (designer's boastful estimated), 79 mi (127 km) (actual).
- Maximum speed: 300 mph (483 km/h; 261 kn) (designer's boastful estimated), 35 mph (56 km/h) (actual).
Aircraft of comparable role, configuration and era.
- VZ-8 Airgeep
- Chrysler VZ-6
- Curtiss-Wright VZ-7
- Piasecki VZ-8 Airgeep
- Bell Helli-jeep
- Hiller Flying Platform
- De Lackner HZ-1 Aerocycle