Editing Avro Canada (section)

==Avro aircraft experimental designs==
Additional developments of the Arrow were explored by Avro's '''Project Research Group''' under the leadership of Mario Pesando.

===Arrow Mk.3===
Even before the Arrow first flew, Avro was designing a future version, the Mark 3. Originally designed for Mach 2.5, later revised to an estimated Mach 3 with a combat ceiling of 70,500 feet, it carried more fuel, weighed over 25% more than the Mk.2, and made greater use of CNC machining and high-temperature aluminium alloys. Also proposed was a heat shield forming an ablative insulation made from carbon fibre or fibreglass in a honeycomb matrix, later used on [[NASA]]'s [[Project Mercury|Mercury]] and [[Project Gemini|Gemini]] programs. The engine was to be the Iroquois Mk.3, which Orenda estimated would provide 40,000&nbsp;lbs of wet thrust (with afterburner). Images of the design show revised engine intakes projecting out from the fuselage to swallow the supersonic shock wave to reduce drag and increase thrust. Also proposed was capability for "probe and drogue" aerial refuelling made possible by the Arrow's revolutionary flight stability systems.<ref>Whitcomb 2008, pp. 205–207.</ref>

===Long Range Arrow===
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In early 1957, studies began on how the Arrow Mk.2 might be developed into a "Long Range Arrow" to meet the requirements for the USAF's Long Range Interceptor Experimental (LRIX) program. This was thought to be suitable as under the terms of various agreements, statements, and promises to Allied and in particular Commonwealth nations, the U.S. would buy weapons from an ally if they were the best available and the Arrow seemed to fit this description. Shortly in advance of the USAF visiting Avro in 1955 to review the Arrow's development, a contract was granted to North American Aviation for design studies for the LRIX, designated the [[North American XF-108 Rapier]].  Performance requirements were for a range of 1,000 miles, Mach 3, and combat altitude of 60,000 feet. In September 1957, Avro's Project Studies PS-1 and PS-2 were released. PS-1 included addition of wingtip-mounted ramjets to supplement the main engines and a canard mounted above and behind the cockpit. PS-2 included wing extensions, an extended nose with retractable canard, two additional vertical stabilizers mounted on the wings, and four large ramjets. Estimated performance included sustained speeds of Mach 3 at 95,000 feet and vertical climb rate above 40,000 feet of Mach 2.5. The thrust-to-weight ratio would have been double the F-108 and over double the SR-71.

===Arrow Mk.4===
At the request of USAF Chief Scientist, a less radical modification of the Arrow than the PS-2 was pursued which became the Mark 4.<ref>Whitcomb 2002, p. 157.</ref> The revised intakes of the Mark 3 were retained, but with smaller [[Curtiss-Wright]] ramjets, without the canards and nose extension, and with a titanium skin instead of a heat shield. Performance was reduced to Mach 3 and  maximum combat altitude of 80,000 feet.

===Supersonic Avrodynes===

In 1952, Avro Chief Designer John Frost selected a group of eight engineers and draftsmen to create the Avro '''Special Projects Group'''.  In its intense exploration of radical aeronautical design ideas and development of new technology, as well as security, the SPG resembled Lockheed's "Skunk Works".<ref>Zuk 2001, p. 41.</ref>  Initial projects included research and development work on a series of "[[flying saucer]]"-like vehicles. The only design that materialized beyond mock-up was the VZ-9-AV Avrocar, funded entirely by the U.S. military from 1956.<ref name="Frontiers"/>

* '''Project Y1:  "the Spade"'''
[[File:Project Y mockup colour.jpg|thumb|right|Project Y mock-up in the Experimental Flight Hangar c. 1954.]]
Design reports from early 1952 outlined key features of a new gas turbine propelled engine and disc-shaped vehicle:  an inner disc with central eye intake with an outer, counter-rotating disc, with rear-directed thrust nozzles, later refined  to include controlling the aeroplane by [[thrust vectoring]] and stabilizing the vehicle by having the large engine rotor act as a gyroscope.<ref>Zuk 2001, pp. 41–43.</ref> The aircraft was designed for vertical take-off and landing which was thought to be hazardous and required an electronic flight-stabilization system, then not-yet available. Financed largely by Avro, the Canadian government deemed these problems too expensive to finance beyond an initial funding of $400,000. A USAF-led delegation to Avro in December 1953 gave Avro the opportunity to discuss their projects, but Y-1 was not deemed worthy of financing.

* '''Project Y2'''
In mid-1954, Frost proposed "Project Y-2:  Flat Vertical Take-Off Gyroplane" in response to requests by the US Air Force and US Navy for "vertical rising point-defense fighters".<ref>Whitcomb 2002, p. 100.</ref>  In late 1954, the USAF purchased the development rights to this saucer-shaped VTOL vehicle powered by more conventional engines than, and designed to avoid many of the problems with, the Y-1. The USAF designated it '''Project MX-1794''' and studies of the Avro saucer designs '''Project Silver Bug'''.  Through 1958, Avro spent $2.5 million and the USAF $5.4 million funding the project.  Numerous models were constructed and wind-tunnel testing was undertaken at MIT and Wright Patterson Air Force Base (where Roswell UFO studies were reportedly undertaken).

The design included eight [[Armstrong Siddeley Viper]] turbojet engines, a very large centre rotor/impeller with Lundstrom compressor turbines, with the cockpit mounted in the top/centre. Control was achieved through eight small exhausts at the outer edge, directed either through the top or bottom, in addition to the main turbine exhaust through the bottom/centre of the craft.  A multi-engine test rig was built and tested in 1956, resulting in powerful thrust and a great deal of noise, and vibration.  One Special Projects Group member reported that the prototype was secretly removed by the US Navy for further testing in California.<ref>Whitcomb 2002, p. 104.</ref>

Avro also decided to internally fund development of a radial-flow gas turbine engine vehicle, designated '''PV-704''', which proposed no central impeller or exhaust, but rather a large spinning turbo-disc directing all thrust to the outer rim.  Funding enabled continued development but was insufficient for a prototype.

In 1957, the USAF provided additional funding to extend the project, by then highly classified and designated as '''Weapon System 606A'''.  The concept developed was for a circular-winged, supersonic aircraft. Over 1,000 hours of wind-tunnel testing were performed.  Drawings developed by Avro show an aircraft that appears to be a merging of flying saucer with more conventional fuselage shapes, in other words a tailless aircraft with circular wings (when viewed from above or below).

===Avrocar===
{{main|Avro Canada VZ-9 Avrocar}}
[[File:Avrocar.png|thumb|The Avro VZ-9-AV Avrocar.]]

The Avrocar, also called the Avro 'flying saucer' or Avro disc, was proposed to the U.S. Army as a type of "flying Jeep" that could also serve as a proof-of-concept test vehicle for a later supersonic flying saucer designs, PV-704 and Weapon System 606A.<ref>The Ottawa Journal, October 29, 1959, page 3.</ref> Two Avrocars were built, one for wind-tunnel testing at NASA Ames and the other for flight testing. The designs were underpowered  and only operated in a ground-cushion effect, much like a [[hovercraft]]. When the Avrocar prototypes failed to perform at heights above three feet off the ground, the U.S. Army and USAF cancelled the project, in 1961.

Both Avrocars were on public display, one in Building 22 of the Smithsonian Paul E. Garber facility, the other at the [[U.S. Army Transportation Museum]], [[Fort Eustis]], Virginia. The latter Avrocar was dismantled and put into storage c. 2002, due to increasing deterioration (it was displayed outside, and the museum is very close to the ocean).

The [[curator]] of the U.S. Army Transportation Museum stated in 2008 that it would take between US$500,000 and US$600,000 to entirely restore it. Furthermore, because it is at a federal (military) installation, the work must be done by contractors, rather than volunteers. A grant of US$80,000 was received to begin restoration, however this amount was only enough to restore one piece approximately five ft by five ft.

===Avro STAT (SST)===

===Space Threshold Vehicle===
Developed by the Advanced Projects Group, a June 1958 report by Avro's Engineering Department described a Space Threshold Vehicle intended to "get a man into the threshold of space and recover him, flying back through the corridor", where winged flight was possible between maximum altitude that could sustain lift from a winged vehicle and maximum tolerable structural temperature.<ref>Whitcomb 2002, p. 236.</ref> This was estimated to be an altitude of between 150,000 and 200,000 feet. The STV would have had capability for in-flight refueling, and an expected speed of 6,000&nbsp;mph (Mach 8.5+).<ref name="Whitcomb 2002, p. 241">Whitcomb 2002, p. 241.</ref>

Avro's computer capacities provided capability in developing theories and methods similar to modern three-dimensional modeling of fluid dynamics. Avro envisioned a delta-shaped vehicle with downward winglets (similar to the [[TSR-2]]'s), varying engine nacelle positions, titanium skin, and first flight of a research vehicle in 1962. Many engineers involved in this and similar Avro designs were later heavily involved in NASA Projects Mercury, Gemini, and Apollo.<ref name="Whitcomb 2002, p. 241"/>

===Avroskimmer===
This group of vehicle designs were variations on what later became known as hovercraft.

* Avrocruisier
* Avrowagon
* Avroflivver
* Avro P470 Mobile Ground Effect Vehicle

===Other designs===
* [[Avro Canada TS-140]], A Mach-2 VTOL fighter proposed to the US Navy.
* XA-20 and XA-92 Bobcat, similar to designs for later armoured tracked vehicles.
* Turbine-powered trucks, monorail transit.
* Orenda OT-4 turbine powered [[White Motor Company|White]] 7000 transport truck with an [[Allison Transmission|Allison]] engine.
* Orenda OT-4 turbine powered M-48 Patton tank. The American [[M1 Abrams]] would be the first [[main battle tank]] in production (1980) powered by a turbine engine.
* Hydrofoil Warships: When the Arrow and related programs were terminated, 12 key engineers from this team departed for De Havilland Aircraft of Canada. to work on what became [[HMCS Bras d'Or|HMCS ''Bras d'Or'']], possibly the world's fastest warship to present day (2011).