The E67 design was for a vertical take off and landing aircraft for executive use. Vertical flight capability was achieved by using the tilt wing concept. In the initial version of the design power was provided by two Rolls Royce H1400 Gnome turbo shaft engines driving two 16 ft. diameter propellers. Cross shaft interconnection between the propellers was included in the layout. Subsequently the need for four engines to cater for an engine failure condition in vertical flight became apparent. The pressurised cabin was designed to accommodate up to 18 passengers in a high density feeder role. Conventional design techniques were used throughout. A market survey showed that the design had significant advantages relative either to a helicopter or a twin jet executive type (Reference 3).