 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.