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).
Flywheel vibrations on the 40/50 engine.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan113 | |
| Date | 7th January 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c.c. to SS.{S. Smith} c.c. to Nor. c.c. to E.{Mr Elliott - Chief Engineer} c.c. to BY.{R.W. Bailey - Chief Engineer} x6341 FLYWHEEL VIBRATIONS ON 40/50. We have now arranged our optical apparatus for measuring flywheel vibrations for the 40/50 engine. The mirror holder is fitted to the clutch trunnion guide, the gear-box being absent. On the 25 HP. we got vibrations with no gear-box 600 R.P.M. lower than observed on the road with a gear-box. This we consider due to the constraint provided by the first motion shaft to axial angular movement of the flywheel, for if the flywheel deflects a bending moment is produced in the first motion shaft tending to bend it into a curve. On the 40/50 due to the fabric joint no support is given to the flywheel by the gear-box. Hence we should expect the speeds of vibration observed optically to coincide with those found in a car on the road. This we find to be the case, good examples being 58-M.H. and 25-EX. chassis. Disturbances commence at 2050 R.P.M. or 54 M.P.H. on top gear, the major vibration being at 2500 R.P.M. or 66 M.P.H. It will be seen that the type of vibration is the same on both engines and that the worst vibration occurs at nearly the same speed. We shall shortly examine these vibrations on the engine fitted with balance weights, at present in 24-EX. Hs{Lord Ernest Hives - Chair}/H.Grylls. | ||