From 'Percival & Hunting Aircraft', John Silvester, self-published, page 183 :-
"... a further design study, the P.105, was produced in which the main rotor assembly and gas generating units were arranged to form a compact unit complete with an auxiliary gearbox and tail rotor coupling. It was envisaged that the fuselage would be a separate unit on to which the rotor/gas generating system would be mounted; an arrangement that allowed greater freedom in the design and particularly important in view of the various roles envisaged.
In an optimistic brochure issued by the company in August, 1955 (to quote) ' ... based on the measured efficiency of the gas-drive system which has been tested on the Hunting Percival P.74 research helicopter, coupled with various improvements which enable full advantage to be taken of the inherent simplicity of the tip-driven rotor. . .', two of the possible roles were described together with a detailed description of the gas-generating system.
Couched in very positive terms, the description stated that the rotor was 63 ft in diameter and had three blades constructed of stainless steel with light alloy tail fairings and that the cast stainless steel hub structure was mounted on two taper-roller bearings and accommodated the blade flapping bearings of the plain type ... which required no lubrication.'
An artist's impression depicted the two gas-generating units mounted at the tips of a short stub-wing to form a single unit with the rotor support structure together with the auxiliary gearbox, tail rotor drive-shaft and the oil system enclosed within a light alloy fairing. One of the roles described was a general-purpose helicopter, the other an aerial crane."
Also these, from 'Project Cancelled', 2nd edition, page 100 :-