From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Experience with wire ropes used for winch-launching gliders at private clubs.
| Identifier | ExFiles\Box 175\2\ img072 | |
| Date | 19th February 1941 guessed | |
| SECRET. Memorandum on wire ropes suitable for winch - launching. Experience with Private Gliding Clubs. Winch launching was much used by private gliding clubs, both for training and for sporting flying purposes. The winches used were mostly built by amateurs and they lacked the refinements that are expected on a winch built specially for the purpose by an engineering firm. The wear and tear on the cables was consequently greater than it need have been; factors contributing to this were, uneven winding on the main drum, use of pulleys of insufficient radius and inadequate lubrication and care of the cable. If full attention is given to these points the 'life' of a launching cable could be considerably increased. 2. Cables with breaking strains of 15 - 20 cwt were used by most of the clubs. Cables with a rope centre were found preferable to those with a steel core as the rope helps to lubricate the wire strands; they are also easier to splice. These ropes were used for launching gliders with an all up weight of not more than 700 lbs giving a safety factor of between two and three. A safety factor of two should be adequate if the cables are properly maintained. | ||