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).
Bentley chassis vibration tests, concerning the torsional vibration of the frame forward of the dash.
| Identifier | ExFiles\Box 3\6\ 06-page285 | |
| Date | 24th October 1934 | |
| To E.{Mr Elliott - Chief Engineer} c. to Mor. c. to By.{R.W. Bailey - Chief Engineer} x4153 Ha/PJH.14/KW.24.10.34. BENTLEY CHASSIS VIBRATION TESTS. This report is additional to Ha/Tym.16/KW. 11.10.34, and concerns the torsional vibration of the Bentley frame forward of the dash. The tests were carried out with chassis 1-B-IV and a vibrating machine loaned to us for one day through the courtesy of Capt. Wilks, Managing Director of the Rover Co., Coventry. This machine was capable of giving impulses in a vertical direction at frequencies adjustable from 400/min. to 850/min. to each of the front wheels. The impulses were produced by out of balance weights mounted on short lengths of shaft under each front wheel. These shafts were driven by belts from a common shaft running across the machine. This method of driving the shafts was a disadvantage for torsional vibration tests, because the two shafts did not keep perfectly in step, one gaining a revolution on the other approximately every 5 secs. The result was that any torsional vibration set up was damped out every 5 secs. and resonant vibrations did not have time to build up to their maximum. However, with slight modification the machine would be exceedingly useful for investigating front end movement because, owing to the fact that the wheels do not rotate it is possible to separate front end movement from gyroscopic wheel disturbances. The machine is at present being used by Rovers for testing coachwork. By measuring the speed at which the peak frame deflection occurred, the frequency of the standard Saloon being tested was found to be about 670 per min. which increased to 700 per minute by fitting the cross member between the lamps. The frequencies of the stabilisers were later determined by eye approximately by running the engine light with two cylinders only firing. The results were - (1) With the Wilmot Stabiliser 690 per min. (2) With the Rover Stabiliser, full wts. 650 " " (3) " " " half " 680 " " | ||