Notes on the Planet Satellite.

Planet Aircraft Ltd was set up as a susidiary of F.A.Hughes & Co Ltd, (who produced magnesium) by Major J.N.D. Heenan a Consulting Engineer with no previous experience of aircraft design. F.A.Hughes (& hence Planet Aircraft) were taken over in 1946 by the Distillers Company.
Heenan wanted to create a cheap aircraft that was constructed like a Lobster or crab claw, (one that is truely monocoque), but needed a material that was less dense than aluminium. 
Refining methods & production of Magnesium had improved over the WWII period & an alloy of Magnesium & Zirconium was found that was sufficiently strong, & corrosion resistant with suitable Chromate & paint treatment, but was 40% less dense than aluminium.
Design work started in April 1946 on an aircraft that could seat up to 5 persons in comfort & relative silence, & have good visibility. Cheapness of construction would ensue from the monocoque structure as it would require less drawings & parts.

The wing was made in 28" long sections without a structural spanwise spar, & the fuel tankage was in nylon crashproof bags.

Some test pieces of the wing design were made & tested satisfactorially for fatigue & ultimate strength by the National Physical Laboratory.

As the fuselage required a break to gain access to the engine compartment, a novel use of a rack & pinion device ensured that the control runs could automatically connect & disconnect. Once the fuselage had been separated, the engine could be slid aft on rails.
The engine was force cooled by a fan with the air exiting via a volute with the exhaust. This system was calculated to recover the loss of thrust from driving the fan.
The undercarriage & flaps were pnuematically operated, & the propeller was an Aeromatic automatically variable pitch design, hence no propeller control in the cockpit.

Production was entrusted to the Redwing Aircraft Company at Thornton Heath near Redhill in Surrey.

The aircraft was statically displayed at Farnborough in September 1948 & later transferred to Blackbushe where after the first hop the undercarriage collapsed. The Air Registration Board requested an investigation into the stressing & after repairs were made it was prepared for a second flight. It achieved a height of 20 ft and was put down gently, but post flight checks showed that the keel structure had cracked & the aircraft was grounded by the ARB.
Further finance was not forthcoming for redesign & repairs so the aircraft languished at Redhill until 1958 when it was broken up.
A second aircraft was registered G-ALXP but was never completed, but its fuselage was subsequently used in the Firth Helicopter.
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Its a great pity that no further work was done on this aircraft as I found when creating this model that it had some very interesting features, & was quite fast & economical for its time. Its flight characteristics have been very easy to adjust also. 

If it had been successful 'Spam cans' may never have looked the same afterwards.............

Information extracted from Flight magazine for July 15 1948 & Aeroplane Monthly for October 1983.

Keith Paine 1/7/12
