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).
Vibration experiments on an 'SS' car, detailing a process of elimination by removing engine parts to identify the source of the issue.
| Identifier | ExFiles\Box 137\4\ scan0024 | |
| Date | 22th July 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/TSN. c. to SG.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to EY. 863H. Hs{Lord Ernest Hives - Chair}/TSN1/MS22.7.29. ORIGINAL Vibration experiments on SS.{S. Smith} We have an "SS{S. Smith}" car mounted with two drums driving the back wheels. The car has an axle-test closed body, and we have been doing tests to investigate the vibrations from the engine perceptible inside a closed car. The engine has sandwich rubber feet. The tappets & push-rods were removed during the tests. The tests were as follows: (1) Cylinder-blocks, head, pistons and rods still fitted. The exhaust valves were removed, to facilitate motoring the engine. There was a lot of noise due to air rushing in and out of the exhaust parts. At 2600 R.P.M. there was a stinging vibration of the steering wheel, which appeared to orginate in the frame side member. The frame vibration appeared worse than that of the engine, particularly at the steering box. There was vibration at the centre of the side panel of the crankcase, very little at the front foot and none at the rear foot. (2) Cyl: Head removed. Distance pieces were put under the nuts on the long studs. We could now detect a lot of noise from the pistons, which appeared to be slapping in the bores at high speeds. They were warm, but not at their usual working temperature of course. The blocks appeared rather unsteady, but the general vibration perceptible inside the car appeared unchanged. (3) Pistons & rods removed. Cyl: blocks, head, camshaft, slipper drive, and auxiliaries still fitted. Almost all the noise perceptible from outside the car had vanished. The steering wheel sting and vibration of the side member was now not detectable below about 3800 R.P.M. From outside the car the engine appeared smooth, as vibration could only be detected by feeling along the crankcase. Inside the car there was still a lot of booming and we picked out 3 distinct periods at which vibration was worst, 38, 28, and 22 m.p.h. in 2nd.gear(2660,2000 & 1600 R.P.M.) At 43 m.p.h.(3000 R.P.M.) and upwards Contd. | ||