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 detailing drawings for new magnesium pistons and connecting rods, outlining design changes and anticipated weight savings.
| Identifier | ExFiles\Box 170\1\ img053 | |
| Date | 18th January 1939 | |
| Telephone: SLOUGH 22248 DIRECTORS: S. SANDERS L. L. TREMLETT, B.A., A.M.I.A.E., M.S.A.E., M.A.S.M.E. A.{Mr Adams} C. BERTELLI (formerly Italian) L. JACKSON TEMPLEWOOD ENGINEERING CO. LTD., 490, IPSWICH ROAD, TRADING ESTATE, SLOUGH, BUCKS. 18th. January 1939. W. A.{Mr Adams} Robotham, Esq., Messrs. Rolls-Royce Ltd., D E R B Y. Dear RM{William Robotham - Chief Engineer}, We attach herewith our drawings as follows :- 130 & 131. Magnesium Piston replacing your split skirt piston E.60632. 132 & 133. Magnesium Piston replacing your "Aerolite" Piston EB.3151. 159 & 160. Forging and complete rod drawing for an RR.56 connecting rod with steel cap. We anticipate a total weight saving per cylinder of 9½ ozs, or nearly 20%, - 5½ ozs. on the piston and 4 ozs. on the connecting rod. With regard to the pistons, we have kept the general thicknesses of the forged magnesium to the same figures as you are now using for cast aluminium. We have increased the diameter of the gudgeon pins to 1" as this is found desirable in magnesium pistons to prevent the bores from opening out and the gudgeon pins coming loose. We have also widened the small end of the connecting rod a little as this spreads the bosses on the piston, which limit the - 1 - Cont'd ... ... ... ... | ||