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).
Over-run vibration, the effect of a lighter flywheel on a 20HP model, and rubber engine mounting.
| Identifier | WestWitteringFiles\S\2April1928-June1928\ Scan069 | |
| Date | 3rd May 1928 | |
| HS.{Lord Ernest Hives - Chair} FROM E.{Mr Elliott - Chief Engineer} Copy to BJ. [crossed out] re. LIGHTER 20HP. FLYWHEEL. [Handwritten: X5300 (crossed out) X4012 / X5005 (crossed out)] Are we sure that the over-run vibration is not intensified by the use of a lighter flywheel? This vibration is appreciable on the 'twenty' down at WW., and appears to reach its maximum at 38 - 40 mph. when slowing down from above 50 with closed throttle. The rubber engine mounting may however permit us to use a lighter flywheel with impunity. A Red-head Chrysler I tried recently was very good on the over-run. The engine was mounted on rubber in a very crude fashion, by lining the inside of the chassis frame with a .250" layer of this material where the engine foot bracket wasfixed, but apparently with the desired effect. This Chrysler had 6/1 compression ratio, and was running on Ethyl petrol. The acceleration was like the proverbial scalded cat. I experienced no torque reaction periods, but it was a closed body. E.{Mr Elliott - Chief Engineer} | ||