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 Rotol Airscrews requesting to use a cold chamber to test the effects of differential contraction on magnesium airscrew blades.
| Identifier | ExFiles\Box 151\3\ scan0376 | |
| Date | 15th February 1940 | |
| TELEPHONE: CHURCHDOWN 322. 1290 TELEGRAMS: ROTOL, GLOUCESTER. [SBAC LOGO] ROTOL AIRSCREWS LIMITED [NATIONAL SCHEME FOR DISABLED MEN LOGO] DIRECTORS: SIR G. {Mr Griffiths - Chief Accountant / Mr Gnapp} STANLEY WHITE, BT. {Capt. J. S. Burt - Engineer} A. {Mr Adams} F. {Mr Friese} SIDGREAVES, O.B.E. A. {Mr Adams} H. {Arthur M. Hanbury - Head Complaints} R. {Sir Henry Royce} FEDDEN, M.B.E. E. {Mr Elliott - Chief Engineer} W. HIVES, M.B.E. CHELTENHAM ROAD GLOUCESTER Our ref: C/LGF/FW/4. 15th February, 1940. Messrs. Rolls-Royce, Ltd., Derby. For the attention of Mr. Robotham. Dear Sirs, We understand that a Cold Chamber is in existence at the Rolls-Royce factory for testing car components under winter conditions, and we should be pleased to have your comments as to its suitability for certain tests which we wish to carry out on magnesium airscrew blades. We attach hereto for your guidance a sketch showing the root of the blade and its adaptor. The blade is screwed into the adaptor and held by dowels, through the flange at the base. A tapered bush of tufnol is then pulled down by means of a ring nut at the top, giving support to the blade above the threads. These blades are in magnesium alloy, while the adaptors are in steel, and the differential contraction under freezing conditions in flight, is considerable. A temperature of 46 degrees of frost farenheit has been recorded on a test flight recently, and assuming an assembly shop temperature of 60°F, this would give a temperature difference of 74°F. {Mr Friese} We are anxious to find out if such differences will materially affect the rigidity of the blade in the adaptor, and if conditions are suitable in the Cold Chamber we would propose to send the root end of a blade with its adaptor for test, the test comprising of checking the extra amount which the adaptor can be screwed on to the blade root at the low temperature condition. P.T.O | ||