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).
Results of a Bentley engine test, identifying the piston as the weakest component and proposing further tests with improved designs.
| Identifier | ExFiles\Box 3\6\ 06-page193 | |
| Date | 11th June 1934 | |
| To E.{Mr Elliott - Chief Engineer} c. to HDF. c. to Ry. c. to Mx.{John H Maddocks - Chief Proving Officer} We have been trying to do a Type Test on the Bentley; the attached report shows the result of the first 50 hours running. This confirms our present knowledge that the piston is the weakest part of the engine. The Aerolite piston people have given us a suggestion for improving the strength of our standard piston; they say that if they use a sand core they reduce the stresses set up in die casting, and they attribute our cracks in the gudgeon pin bosses to the metal core. The other bad feature is the gumming of the piston rings which seems also connected with the piston ring stops. We propose to try a 50 hour run on Aerolite pistons and follow this with a run on standard pistons cast with sand cores, without piston ring stops. Our ultimate aim is that every car engine going into production should be able to pass a type test closely approximating to the aircraft engine requirements. Since the car engine has such a much lower specific output we do not think the proposed test is unduly severe. Hs{Lord Ernest Hives - Chair}/Rs.{Sir Henry Royce's Secretary} | ||