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).
The measurement, amplitude, and hydraulic damping of vehicle axle wobble.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan117 | |
| Date | 1st August 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -5- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG21. 8.25. speed as 30 m.p.h. with a frequency of perhaps little over half that at which it started; which cannot be very near the true criss cross period of the axle. With regard to amplitude of these wobbles. We set our instrument to measure wobbles of over 8° only - we found that any severe wobble was measured. We feel that a really severe wobble would certainly have an amplitude of 11° or over. All the wobbles we have so far measured started with a period which coincided with the period of the wheel revolution. Hydraulic damping. We have a number of experiments in hand with hydraulic dampers. We are arranging :- (a) To damp the steering hydraulically. (b) To damp the criss cross and parallel vibrations of the axle hydraulically by fitting Houdaille in lieu of the standard R.R. (c) To damp the criss cross vibration but not the parallel vibration by means of a hydraulic device. Other tests. We have the test re. the rigidity of the engine suspension in hand. We are repeating the test increasing the moment of inertia of the axle at its extremities. We are confirming the criss cross nature of the vibration and its amplitude by means of the chronograph; Phantom and Silver Ghost. You have asked us to compare the wobbling tendencies of the Phantom and Silver Ghost in terms of lbs. out of balance of the wheels. Our tests are not very satisfactory but on contd :- | ||