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).
Investigating retard vibrations related to the torsional period of the driveshaft.
| Identifier | ExFiles\Box 25\3\ Scan116 | |
| Date | 16th February 1924 | |
| R.R. 402A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} 76324 EXPERIMENTAL REPORT. Expl. No. 9770 634 REF: Hs{Lord Ernest Hives - Chair}2/LC16.2.24. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. RG.{Mr Rowledge} c. to E.{Mr Elliott - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} SECRET. EAC. ENGINE. Retard vibrations. We have carried out further investigations on these vibrations in order to confirm that the period at 42 m.p.h. is the torsional period of the shaft between the engine and gearbox. We reduced the shaft from 1.1" to .9" diameter. The effect of this on the road was to reduce the period from 43 m.p.h. to 32 m.p.h. The intensity of the vibration was also reduced. We consider that when running with the throttle shut, there is a vibration on the EAC. engine which varies with speed - being worse at high speeds. It happens with the std. engine coupling; this vibration tunes with the period of the shaft at 42 m.p.h. This retard vibration can also be affected by the torque reaction dampers. If we remove the torque reaction dampers it is worse at certain speeds. This has been confirmed on the 20 HP. cars as well as the EAC. Retard vibrations is a common complaint on a number of cars but unless it causes a periodic [crossed out text] vibration with the engine mounting or transmission, it is not very noticeable. There is however, a very nice feeling on cars which are entirely free from it. The Hispano car is remarkably smooth on retard. The Delage also had this characteristic. The 40/50 HP. is better than the 20 HP. in this respect. It is exactly the same problem as we had in 1911 on the 40/50 HP. Hs.{Lord Ernest Hives - Chair} | ||