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).
Technical notes on shock absorber settings and spring specifications.
| Identifier | ExFiles\Box 28\1\ Scan034 | |
| Date | 24th September 1924 guessed | |
| - 2 - (6) Although depending on hydraulic resistance, it does not force oil through a small orifice but lifts a valve of reasonable size against a comparatively soft spring. Therefore the effect of the orifice type, like the Houdaille, of being almost "dead hard" in its resistance to rapid movement is entirely missing. Also since the shock absorber action does not take place when the axle moves up, there are no violent blows transmitted to the car when it runs over an obstacle like a brick or a curb. (7) Settings. Five different springs are supplied by the makers. These are approximately:- 40 Lb. Nickel finish 60 " Bronze 80 " Steel 100 " Steel (short) All have 1/4" compression to give the rated load, except the 100 lb. spring which is stiffer and has about 1/8" compression. We do not use the latter. As you will notice from the print there are two valves - A, the "first stage" being open only in the normal riding position of the car and a range of about 2" up or down from normal, B, the "second stage" doing the main work of stopping severe rebounds, either at the top or bottom of the stroke. When equal valve springs are used either valve may work in the normal riding position. The second stage valve is drilled with a small breathing hole which allows the slower movement of the car to occur practically without resistance. C. the inlet valve has a very large area and light spring so as to put very little resistance on the incoming oil. Since the piston is below the oil level, leakage here is important. Our standard settings arrived at by trial are:- 1st. Stage - 40 lbs. spring packed out with 2 fibre K.5010 to give 20 Lbs. pressure. (washers. 2nd. Stage - 40 lb. spring. (For cars used in Maine or in the Central West or | ||