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).
Letter to Mr. Gordon Armstrong regarding the testing and development of dampers.
| Identifier | ExFiles\Box 152\1\ scan0326 | |
| Date | 21th May 1937 | |
| 1293 May 21st.1937 Rm{William Robotham - Chief Engineer}/Les.14/AP. Mr.Gordon Armstrong, Waltham Works, Beverley, E.YORKS. Dear Mr.Armstrong, Thank you for your various letters. I had not realised that you also required castings without steel insert tubes. These are now being made. I was very pleased to hear that you were getting fairly satisfactory results with the single spring valve. We fitted a small clamping disc to overcome the noise and then experienced a nasty fluctuation of load, which I think was due to some presence of air near the damping disc. Personally I cannot see any reason which can prevent this valve working. As other work in our testing section has been very urgent, no damper tests have been done for over two weeks. I am very keen to try to convince myself and others that your type of damper will not knock with slack bearings. It would be very useful if you could let us have a damper with as slack bearings as possible which does not knock. I am certain this is a very important item and would make all the difference in the interest of your dampers at Derby. We have been testing the balance valve dampers and find that the difference between the soft and the hard position in height of indicator diagrams is practically nothing. The static load came out at 60 lbs. soft position and 110 lbs. in the hard position. This range is also too small. In order to get a poundage as low as 60 we had to put a spring holding the top plunger in contact with the shaft. We cannot notice any real difference in load due to the cam action on the shaft. In order to get the maximum use of the cam I suggest it should begin to rise immediately after the normal position towards rebound and reach the full diameter of the shaft after 25 degrees of movement. continued | ||