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 Mr. Robotham in New York to Mr. Hives discussing piston performance, engine comparisons with American cars, and potential Bentley improvements.
| Identifier | ExFiles\Box 173\2\ img293 | |
| Date | 5th March 1934 | |
| GRY{Shadwell Grylls} New York, N. Y. March 5, 1934 To: Mr. Hives From: Mr. Robotham Thank you for your HS{Lord Ernest Hives - Chair}/GHY-7-KW/16234 containing the requested information. I shall definitely order a set of pistons. The final confirmation of the power characteristics of the Aero-lite pistons is interesting. On the Bentley where we must have an excellent output I believe the Aero-lite piston will be worth while. I still consider the Bentley is far behind the chief American car in - (1) Silence, particularly with regard to valve gear and timing gears. (2) Exhaust system. There is more noise from the Bentley exhaust system than from the Pontiac or similar American car. (3) Roughness. I do not think that at maximum speeds we are so bad, but the 3700 r.p.m. period and fly wheel period are really quite intolerable. I have come to the conclusion that we do not get enough out of our high compression, short toe type camshaft and free exhaust to compensate us for the disadvantages, and that we should do far better to have a supercharger of the centrifugal type and use the 20/25 camshaft and the exhaust system. The disc fly wheel and the engine mounting should help us out of our roughness. You will have had my wire about chamfering front brakes. What we really want on the Bentley are springs passing under the front axle so that we can reduce the twisting moment of the brakes, alternatively springs shackled at the rear instead of putting the top of the spring in compression. We have suffered under the inventive genius which refused to use our original arrangement of torque arm which was like this. However, I presume the chances of getting any drawings on the subject are somewhat remote. I am not looking forward to meeting Dick Sommers. Yours very truly, W. A.{Mr Adams} Robotham D | ||