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 Light Production Co. Ltd. discussing the contour of a piston after an endurance test.
| Identifier | ExFiles\Box 86\2\ scan0120 | |
| Date | 31th October 1933 | |
| THE LIGHT PRODUCTION Co. Ltd. PROPRIETORS OF THE LONDON PISTON RING CO. LTD. ENGINEERS CHAIRMAN & MANAGING DIRECTOR: M.{Mr Moon / Mr Moore} V.{VIENNA} ROBERTS. DIRECTORS: C. E.{Mr Elliott - Chief Engineer} GEORGE. WM THISTLE. TELEPHONE:- VICTORIA 0671. 8 LINES. OUR REF. CHB/IR 60/66, ROCHESTER ROW, WESTMINSTER, S.W.1. ENG. WORKS & GOODS ADDRESS: 61/67, GREENCOAT PLACE, WESTMINSTER, S.W.1. All communications to be addressed to the Company. ON ADMIRALTY, WAR OFFICE & AIR MINISTRY LISTS. TELEGRAMS: INLAND NAPOLEONIC, SOWEST, LONDON. FOREIGN NAPOLEONIC, LONDON. CODES: A.B.C. 5TH. EDITION. YOUR REF. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/KT 31st October 1933. Messrs. Rolls Royce Ltd., Experimental Department, DERBY. Dear Sirs, We think you will be interested to receive a copy, which we attach herewith, of a graph we have prepared after having explored the contour of the pressure face of the piston which you returned for our examination after it had been through your endurance test. We have super-imposed this graph on the graph of our Standard Cam Formations, and you will observe that, in spite of the care taken to follow the normal contour when increasing the clearances as you did, there has been a considerable departure from the correct shape. The interesting point is, however, that the diameter of the piston at the points where the actual bearing surface was obtained after your adjustment, which occurred at approximately 22½° from the major axis position, agrees within two ten-thousandths of that which would have been obtained at this point if the piston had been ground with our No.14 cam. Also you will see from the graphs that this form would give an increased clearance of .0025" at the 45° axis - namely the point immediately above the centre line of the flutes - and would thus avoid a hard bedding at this point. the | ||