Model of the 'Oryx' aircraft gas-turbine
Quarter-scale model of the "Oryx" aircraft gas-turbine. Gas turbine, gas-generator. 12 stage axial compressor, 2 stage turbine. Auxillary air compressor, 4 stage axial flow. Weight 500 lb.
This ¼ scale model engine shows a design that was specifically developed to provide a means of driving helicopter rotor blades by reaction jets at the blade tips. Two of these engines were fitted to the Hunting Percival P.74 Helicopter and were used to evaluate the application of a blade tip drive which would be torqueless i.e. would not need a means to counter the rotor torque. A similar drive was used on the Fairey Rotodyne helicopter but with a different power unit.
Basically, the engine is a normal axial flow compressor gas turbine with an auxiliary air compressor driven off the same shaft at the rear end. Exhaust gases from the turbine are mixed with the delivery from the auxiliary air compressor and are then deducted to the hollow rotor blades, the tip jets driving them on the reaction principle.
Performance: equivalent h.p. 900 at 22,000 r.p.m. Power/weight ratio. 1:.55.