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 investigating axle shock damping trouble and its effect on pitching for the 32. EX. model.
| Identifier | ExFiles\Box 91\1\ scan0349 | |
| Date | 24th June 1936 | |
| y 300a 87 HOTEL DE FRANCE. CHATEAUROUX. Indre. France. GWH{George W. Hancock - Head Chateauroux}/HFH{Hoppy F. Hamilton}/3/JAB. 24th June 1936 To: Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} LBS- DAMPING ON 32. EX, EFFECT ON PITCHING. We have further investigated the axle shock damping trouble experienced on 32. EX. It has been repeatedly reported that the damping is inadequate and allows the car to pitch fore and aft over undulating surfaces. On the 26th of last month, the dampers were removed and the initial poundage checked, this was found to be correct. Leslie therefore advised us to reduce the valve washers in the front dampers by .015", which gave us the required damping control at the front of the car, but still allowed the rear to kick up on bumps. We have now fitted a pressure gauge to the damper unit pump and found the maximum poundage to be 15 lbs. at 70 MPH. this was obviously too low, and was accordingly increased to 25 lbs. at 70 MPH. full maximum. The result is that the car is stable to handle and rides without pitching. The back axle has ceased to jazz and patter, and the general ride and road holding has improved by 30%. We found that owing to the increased damping obtained, the thinner front damper valve washers gave us too much front damping, we have therefore put the standard washers back as first fitted. We consider that the behaviour of the car on all surfaces is now satisfactory and is as good as any Phantom III. we have previously tested. We would like to mention that the maximum poundage obtained on the full minimum position is only 3-4 lbs at 85 MPH. We think this is too low. Should we reduce the distance washer accordingly, so as to increase this poundage to a safe limit ? The foregoing remarks might interest E.{Mr Elliott - Chief Engineer} (reference E.3/HP.4.6.36). ----------------- GWH{George W. Hancock - Head Chateauroux}/HFH.{Hoppy F. Hamilton} H.{Arthur M. Hanbury - Head Complaints} Hamilton. | ||