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).
Report page detailing shock absorber settings, recommended valves, and poundage testing procedures.
| Identifier | ExFiles\Box 55\4\ Scan241 | |
| Date | 13th July 1928 guessed | |
| - 3 - They can be inserted and removed in about 10 minutes per pair of instruments, which is practically nearly as quick as adjusting the needle valve on a Houdaille. (3) SETTINGS Front 80 up 100 down Rear 60 up 100 down RECOMMENDED VALVES FRONT. "Tight" A-12294 "Medium" A-12293 "Easy" A-12217 REAR "Tight" A-12217 "Medium" A-12180 "Easy" A-12181 Valve A-12217 hisses in front instruments, but not in rear. Valves A-12180 and A-12181 allow a certain amount of rear axle chatter when braking suddenly on "washboard" roads. The combination of A-12217 front and rear is quite good up to 40 m.p.h. Above that speed for best riding A-12293 in front and A-12217 in rear gives good "firm" control. A-12293 front and A-12180 rear gives good medium damping action for longish bodies driven at moderate speed, on good macadam with some waves, i.e. typical American conditions. POUNDAGE. We have entirely stopped trying to weigh the poundage at the ball because of the varying amount of mechanical friction within the instrument. Instead we set the valves to the attached table which gives theoretical (frictionless) relation between ball poundage, oil pressure, and valve spring load. The L.P. valve is set to blow off at 143 lbs/sq. in. front and 248 lbs/sq.in. rear, and the H.P. valve springs are set on the spring-testing rig (See A-12175 attached) to exert 13-3/4 lbs. in front and 23-3/4 lbs. at rear. Occasionally we test blow off pressure on the H.P. side with a solid valve in place of the slotted one. We also give the shock absorbers after finishing them, a short run on the active test rig (6" stroke 120 cycles/min.) to make sure that there is no excessive mechanical friction, no dirt under low pressure valve, and a smooth action, as shown by the indicator needle. (Continued) | ||