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).
Letter from the Royal Air Force discussing the specifications for a launching winch.
| Identifier | ExFiles\Box 175\2\ img081 | |
| Date | 1st March 1941 | |
| SECRET Headquarters, Central Landing Establishment, Royal Air Force, Ringway, Nr. Manchester. Ref:- CLE/S.1406/2/S. 1st March, 1941. [Handwritten note: file] [Handwritten note: JC6] [Text circled: Launching Winch.] Dear Sirs, Thank you for your letter (Ref:-Rs.{Sir Henry Royce's Secretary}14/ET) of 26th February, 1941 regarding the above. 2. The amount of cable that can be wound on to the drum will depend on the evenness of winding. Random winding requires about twice the space of even winding. 3. The initial diameter of the drum should not, for practical reasons be less than 12". The minimum correct diameter of pulleys or drums for 1/4" diameter cable is 30 X 1/4" = 7 1/2", but with splices in the cable a diameter of 12" for the drum would give better results. 4. It should be borne in mind that the cable speed is proportional to the speed of rotation and the winding diameter of the drum, this latter will depend largely on the gearing of the winch. Also that at the beginning of the launch when the winding diameter is small as no cable is wound on, the maximum cable speed is required to get the glider off the ground, and at the end of the launch when the winding diameter is large, only a small cable speed is required. 5. The initial diameter of the drum must be a compromise of these factors. 6. The drum should be capable of accommodating up to 3500 ft of cable. 7. It is assumed that the 1/4" cable mentioned in your letter is either the 35 cwt or the 45 cwt cable mentioned in our letter of the 17th February. Please confirm exactly which cable it is. [Handwritten note: 45 cwt cable] Yours faithfully [Signature: R.E. Harvey] Group Captain, Commandant, Central Landing Establishment, Royal Air Force, Ringway. Messrs. Rolls-Royce, Ltd., Derby. | ||