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 discussing specifications, testing requirements, and ordering of various rubber components.
| Identifier | ExFiles\Box 104\1\ scan0027 | |
| Date | 4th December 1928 guessed | |
| contd :- -2- a set of rubbers with approximately this rating. In addition to these slightly stiffer rubbers, we require some very hard rubbers. A figure we suggest is 1.050" long to give a load of 900 lbs. at .050 deflection. You will observe that when fitted in the engine foot, the load to compress our present standard rubbers .150" varies considerably. It is this that we wish to avoid, as it is difficult to keep the engine alignment correct if the rating of the rubbers varies. We have asked our Works to specify .180" deflection at 750 lbs. load for the next quantity of rubbers they order and to reject those outside a limit of +- .007 at this load. This is about the stiffness of the rubber we are at present using. We should like to know if you think you will have any difficulty in working to this limit, if not, can we reduce it? You will of course retain the same mix as that of the sample we are sending you. We should like you to send us three dozen of these rubbers to this limit as soon as you can, also 2 dozen of the stiffer rubbers free length 1.125" (curve C. approx.) and 2 doz. free length 1.050 (curve D.{John DeLooze - Company Secretary} approx.) of the very stiff rubbers. As soon as we have proved their advantage in reducing permanent set, we hope to standardise the rubbers to curve 'C'. Yours faithfully, Our official order will be following - We are also asking you to supply, 2 doz. 20HP rubbers to curve "X" | ||