The first Silver City air ferry operation began with the flights between Lympne, UK and Le Touquet, France with just one airplane in 1948. The distance was only 76 kilometers.
By 1952, the air ferry operation had proved a great success - but there was often an imbalance between outward and return loads. A larger aircraft with a bigger payload but lower operating costs would help to overcome the problem.
The result was the Bristol-170Mk32 or 'Superfreighter'. This could carry three cars and the passengers. Silver City ordered 6 of the new aircraft at a cost of £90000 (or US$ 3.5 million in 2022 money) each for delivery in the spring of 1953.
Griffith Powell, Silver City's Managing Director, speaking in June 1952 mentioned the possibility of using large helicopters by 1960 to carry detachable car-carrying containers over the channel.
These large containers could be loaded and unloaded without the need for the helicopter to remain, thus getting better utilisation of the aircraft. Enamoured with this possibility, Powell's outline specifications were issued to two British manufacturers. In 1952 there were only 11 operational helicopters in Britain so the "flying-crane" concept was some way off.
The Fairey Rotodyne appeared in 1954 and went some way towards this concept, without the detachable containers, but that project would eventually be cancelled in 1962.
Blackburn Aircraft were developing a cargo lifting helicopter, the SP60 as it was code named, it would have a speed of 275km/h and could carry up to 18 cars or 250 passengers in preloaded pods. This was exactly what Silver City was after but Blackburn failed to produce the final product in the end.
Time was running out for Silver City, their air ferry operations declined. Finally, Silver City became part of Air Holdings in January 1962 and the large helicopter project was consigned to history.