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).
Issues and tests on Lovejoy and R.R. friction-type shock absorbers.
| Identifier | ExFiles\Box 55\3\ Scan211 | |
| Date | 12th June 1926 | |
| Oy1-E-61226 -2- June 12, 1926. 2. After trying every conceivable combination of valves in front and rear Lovejoys on four cars during a period of a month we are forced to conclude that they will not compare with the R.R.friction-type (at its best) in riding quality or stability. The specific troubles are:- (1) The "easing-up" of the front shock absorbers after about 15 miles of running. We believe this is due to foaming. (2) The harsh treatment of the front end of the car from rapid movements of the front axle such as occur on "washboard" roads. The attached report of June 1st goes into the matter in rather more detail. We have taken tests of the Lovejoy oil which agree with the figures given in your Experimental report Hs {Lord Ernest Hives - Chair} /Kl/T26.5.28. We are now proposing to try whether heavier oils will overcome the tendency to foam. 3. Single acting shock absorbers. We suggest that Lovejoy shock absorbers front and rear may have a defect inherent in all single acting shock absorbers with jerky action, in that, whether the car goes over a bump or a hollow, the result is a downward pull, which may help to produce pitching. The pitching speed of all our cars is about 120 oscillations per minute. The period of a half-swing is therefore 1/4 sec. When a car with 12 feet wheelbase is going 33 m.p.h. it travels the distance between front and rear wheels in 1/4 sec. Pulls from the shock absorber straps due to passing over an isolated obstacle at 33 m.p.h. would therefore be timed to set up fore and aft pitching. 4. R.R.friction type with short arms. As far as can be judged by a test of only a few hundred miles on one car, the R.R. friction shock absorbers can be much improved in their action by shortening the arm from 8" to 5" (mounting the lower ball behind the axle instead of in front). | ||