The Fairey Rotodyne was designed in the early 1950's as a short haul passenger aircraft capable of flights from the CBD of one city to that of another, without having the need for a runway. The design was a combination of autogyro for cruise flight and jet powered rotors for VTOL flight. The use of jets at the tips of the rotors might have been something developed by Fairey as it the system was also used on a small helicopter developed at the same time. The Fairey Rotodyne was a large hybrid rotorcraft, known as a compound gyroplane or Gyrodyne. According to aviation author Derek Wood, it was "the largest transport helicopter of its day". It featured an unobstructed rectangular fuselage, capable of seating between 40 and 50 passengers; a pair of double-clamshell doors were placed to the rear of the main cabin so that freight and even vehicles could be loaded and unloaded. The Rotodyne had a large, four-bladed rotor and two Napier Eland N.E.L.3 turboprops, one mounted under each of the fixed wings. The rotor blades were a symmetrical aerofoil around a load-bearing spar. The aerofoil was made of steel and light alloy because of centre of gravity concerns. Equally, the spar was formed from a thick machined steel block to the fore and a lighter thinner section formed from folded and riveted steel to the rear. The compressed air was channelled through three steel tubes within the blade. The tip-jet combustion chambers were composed of Nimonic 80, complete with liners that were made from Nimonic 75. For takeoff and landing, the rotor was driven by tip-jets. The air was produced by compressors driven through a clutch off the main engines. This was fed through ducting in the leading edge of the wings and up to the rotor head. Each engine supplied air for a pair of opposite rotors; the compressed air was mixed with fuel and burned. As a torqueless rotor system, no anti-torque correction system was required, though propeller pitch was controlled by the rudder pedals for low-speed yaw control. The propellers provided thrust for translational flight while the rotor autorotated. The cockpit controls included a cyclic and collective pitch lever, as in a conventional helicopter. The transition between helicopter and autogyro modes of flight would have taken place around 60 mph, (other sources state that this would have occurred around 110 knots); the transition would have been accomplished by extinguishing the tip-jets. During autogyro flight, up to half of the rotocraft's aerodynamic lift was provided by the wings, which also enabled it to attain higher speed. https://www.youtube.com/watch?v=EA3AkvxwS_M While the Rotodyne concept was proven, other factors, notably the British Economy, caused the production of the Rotodyne to be cancelled. For more detail of this unique design, click here. As good quality photos of the Rotodyne are difficlut to come by, some of the photos are of the Airfix model.
