From Daniel Robinson
The problems outlined in your article on hybrid helicopters (16 October, p 20) have been solved several times during the history of flight. One notable British example was the Fairey Rotodyne, designed in the 1950s by the same company that produced the Swordfish torpedo bomber, used by the Royal Navy in the second world war.
The Rotodyne had two turboprop propeller engines for forward flight, and rotor blades for vertical take-off and landing. The clever part of the design was the way the rotors were turned: high-pressure air bled from the engines’ compressors fed jets at the tips of the blades.
This eliminated the problem of torque, so the Rotodyne had a conventional tailplane rather than a tail rotor. Sadly, although the prototype performed successfully, it fell victim to government spending cuts and never went into production.
St Albans, Hertfordshire, UK
