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).
Response to a questionnaire regarding the B.12.AW chassis, covering dampers, gearbox, and brakes.
| Identifier | ExFiles\Box 146\5\ scan0341 | |
| Date | 26th April 1940 | |
| 1245 Sr. from Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}3/JS.{Mr Johnson's Secretary}26.4.40. Re B.V. Chassis B.12.AW. We give herewith answers to your questionnaire Sr/VA.4/ET.12.4.40: 1. We have already sent you a drawing of the front shock damper valves. The damper load to open the main valve should be 125 lbs. Owing to the large amount of leak now used on dampers it is difficult to measure the valve load in the normal way. The best procedure is to block up the leaks temporarily. The valve load can then be set accurately. The leaks should be such that a 25-lb. weight on the end of the arm should cause it to fall through an angle of 22 1/2 deg. in 3 secs. The same setting applies to the upward stroke. The leaks on your dampers consist of holes drilled through the rivet in the middle of the replenishing valves at the bottom of the pistons. These holes are susceptible to dirt and should be blocked up. They should be replaced by 90 deg. V grooves cut radially across the face of the seats on the replenishing valves approximately 0.032" wide and 0.017" deep. 2. We enclose the following arrangement drawings of the gearbox marked up with end clearances: 1st & 3rd Motion shafts. GB.4931. 2nd Motion shafts. GB.4932. Sewo drive. GB.4047. 3. Arrangement drawing of Sero mechanism GB.4089 enclosed 4. The front brake hydraulic damper has a valve consisting of an adjustable orifice. There is no spring loaded relief valve. Therefore the faster the damper is moved the higher the poundage. There is bound to be a certain amount of "stiction" in the gland, bearings, etc. This "stiction", i.e. the load necessary to start movement of the lever, should not exceed 2 1/2 lbs. The adjustment of the orifice should be such that a load of 2 1/2 lbs over and above whatever stiction there is should cause the end of the lever to move 1 1/2" in 3 1/2 secs. Continued.... | ||