Avro Canada VZ-9 Avrocar
[1][2] The Avrocar intended to exploit the Coandă effect to provide lift and thrust from a single "turborotor" blowing exhaust out of the rim of the disk-shaped aircraft.[3] 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.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.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.[8] Frost felt the excellent performance of his new engine would be a natural fit for a VTOL aircraft due to its high expected power-to-weight ratio.[citation needed] For VTOL operations the aircraft was expected to sit pointed up, supported by long landing legs that extended out of the spine.[citation needed] While Project Y continued, Frost had meanwhile become interested in the Coandă effect, where fluid flows will follow strongly convex shapes, something that might be unexpected at first glance.He produced a number of small experimental designs using compressed air in place of an engine in order to select a suitable airframe shape, and eventually decided that a disk was the best solution.The blown disk could attack this problem by being laid out for supersonic performance only, and then using jet thrust to modify subsonic airflow into a semblance of a normal wing.[citation needed] There was some debate about the concept within the USAF, as many groups were attempting to gain funding for their own pet projects, like nuclear powered bombers.[13] In a repeat of the earlier Toronto Star release, in 1955 an extensive article appeared in Look magazine that, among other claims, speculated that current UFO sightings were Soviet-built saucers.[citation needed] To gather flight data on the basic concept while the engine development continued, in 1958 Frost proposed building a smaller "proof-of-concept" test vehicle he called the Avrocar.By this point, the U.S. Army was involved in a wide variety of experiments on smaller VTOL aircraft that would act as a "flying Jeep",[16] and they became interested in Avro's concept as well.Initial performance requirements for the Avrocar were a ten-minute hover capability in ground effect and 25-mile (40 km) range with a 1,000 lb (450 kg) payload.Bernard Lindenbaum of the Air Force Flight Dynamics Laboratory recalls a trip to Washington in the late 1950s to request additional funding for a study on helicopter drag reduction.The 124-blade "turborotor" sat in the center of the triangle, with most of the rotor's thrust directed straight down through an opening in the lower surface, but some was bled off to power the control system running along the outer rim of the disk.[24] The undercarriage of the Avrocar was rudimentary with three small castering wheels mounted on "stub" shafts; a set of skids was substituted later in testing although they were not normally fitted.[23] The attitude/thrust control system consisted of a large ring situated outside of the main disk, shaped roughly like a rounded triangle with the flat surface on the "inside".This was somewhat unexpected; recirculation had been considered a "bad thing" due to the loss of engine thrust, and its positive effects on lift do not appear to have been appreciated.At higher speeds, the doors were closed, allowing the air to flow out from the edge of the aircraft, where a series of simple flap-like controls were located.Both designs used two 2,700 lbf (12 kN) thrust General Electric J85 turbojets and increased the turborotor diameter from five to six ft.[34] 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.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.[37] 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.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.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.After successful tether tests,[39] the saucer designs also at one time publicized as "discojet" were abandoned and their latest project, the Moller Skycar, has a flying-car appearance.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.[41] Data from Avrocar: Canada's Flying Saucer...[42] and The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters[43]General characteristics Performance
Avrocar (band)Proof of conceptexperimental aircraftCanadaManufacturerAvro CanadaJohn FrostUnited States Air ForceUnited States ArmyCold WarCoandă effectflying saucerfighter-likeU.S. Air ForceU.S. Armyhelicopterflight envelopeblue skies research"Jack" Frostde Havillandde Havilland Hornetde Havilland Vampirede Havilland SwallowAvro CF-100Second World WarFrank Whittleflame canscentrifugal compressorcentrifugal fanzero-length launchpower-to-weight ratiodelta wingplaying cardDefence Research BoardToronto Starsupersonicstreamlinesshock waveslouversMach 3.5United States NavyBristol OrpheusBell AircraftD-188Anuclear powered bombersArmstrong Siddeley ViperimpellerCF-105 ArrowfrisbeeContinental J69-T-9center of pressurecenter of gravitystability augmentation systemangular momentumgyroscopeAmes Research CenterNASA AmesT-tailGeneral Electric J85Hawker Siddeley HarrierNational Air and Space MuseumhovercraftSaunders Roe SR.N1Moller SkycarU.S. Army Transportation MuseumSuitland, MarylandSteven F. Udvar-Hazy CenterNational Museum of the United States Air ForceDayton, OhioRoyal Aviation Museum of Western CanadaWinnipegManitobaNemeth ParasolChrysler VZ-6Curtiss-Wright VZ-7Cushioncraft CC1Piasecki VZ-8 Airgeeppolicy by press releaseWayback MachineMilberry, LarryC 102 JetlinerCF-100 CanuckCF-103Hawker SiddeleyHawker Siddeley CanadaOrenda EnginesVictory AircraftA/B/E/F/NL (II)A/B (I)S (II)aircraftthrustAerostatballoonGliderautorotationTethered balloonRotor kiteAirshipAirplaneornithopterAutogyroGyrodynetiltwingtiltrotorballoon helicopterGround-effect vehiclescoleopterFlying Bedsteadflettner airplanekytoonhybrid airshipAirbus Canada2/180 GyroplaneC-102 JetlinerBell Textron429 GlobalRanger505 Jet Ranger X525 RelentlessBoeing Aircraft of CanadaC-204 ThunderbirdA-213 TotemPB2B CatalinaBombardierCRJ100/200/440