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).
Reduction in piston dimensions for the Wraith engine to safeguard against big end failure.
| Identifier | ExFiles\Box 99\4\ scan0124 | |
| Date | 2nd December 1938 | |
| COPY. To HY.{Tom Haldenby - Plant Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}3/JH.2.12.38. PISTONS. With further reference to our memo ref. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} 6/JH.22.11.38. We have now brought the dimension of lands of the RR. piston in line with the Aerolite. At the same time, we shall be giving production a more practical working drawing, by going to parallel grinding. All this is shown on EW.2065 which is instructed in memo BY/NS.{Norman Scott}2/S.26.11.38. In considering the Klingerite gasket for production Wraith, it is desirable that we keep to the thickness of .030", which has been tested and proved satisfactory, but in conjunction with xk section big end bearings (.062), the margin of safety is not sufficient to completely safeguard against the piston hitting the head, in the case of a big end failure. We therefore consider that the piston should be made shorter by .030 by reducing dimensions according, above the line of the gudgeon pin. We are incorporating this reduction of .030 in our more recent experimental 'Aerolite' pistons, so that the two types of pistons will be in line. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||