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).
Design changes for the Bensport engine, focusing on supercharger placement, gear train, and combustion chamber.
| Identifier | ExFiles\Box 3\4\ 04-page061 | |
| Date | 22th June 1932 | |
| E.{Mr Elliott - Chief Engineer} } FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} } XH553 R1/M22.6.32. Sent off 29.6.32. C. to SC. WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} BENSPORT. Owing to the complete change in our programme it would appear that the Bensport engine is likely to be a very long time before it is in a satisfactory condition, and at the moment it seems to be in a very undecided state, so that I am letting Mr.Eyre do some drawing at WN. to help settle the foundation upon which it is to be built. We understand that you may wish to move the supercharger from the front to the side of the engine owing principally to the difficulties of slow running, and snap acceleration, caused by the capacity of the pipe and the possible condensation of fuel. One distinct advantage that I can see from the side position is that the blower would be self draining back into the carburetter if the carburetter were below it. As the intake of the carburetter would be getting low down on such a low car and low engine it might be necessary to have a watertight carburetter fed by an intake that was higher up on the engine so as not to be so liable to pick up water in the case of passing through a stream. To drive a blower in this position it would seem that we must confine ourselves to the rear end train of gears, which is on its way to the camshaft, or camshafts. These gears would be helical and might have some of the intermediate ones of the non-metallic silent type. We also understand that it is probable that your experiments with a separate blower will suggest that the supercharger be put alongside the cyl. block, close up under the induction pipe, in which case the train of gears necessary to drive this blower will be continued up to the camshafts. I am therefore letting Mr.Eyre have a flutter on an imaginary train of gears. Since you and HS.{Lord Ernest Hives - Chair} have decided that it is necessary to have the highest thermo-dynamic efficiency, we are obliged to return to the type of the central ignition plug with the two inclined valves forming approximately a semi-spherical combustion chamber. I have little hope of finding a really satisfactory single camshaft even with short push rods, to work these valves, and fear it will entail the double camshaft as originally schemed. The method of supporting the engine at the front appears to be the same whether we have the blower there, or not. R.{Sir Henry Royce} | ||