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).
Technical memorandum discussing design improvements and weaknesses in engine components like liners, pistons, connecting rods, and controls.
| Identifier | ExFiles\Box 179b\1\ img272 | |
| Date | 21th January 1933 guessed | |
| (2) the P. V.{VIENNA} by the J.{Mr Johnson W.M.} 3. form of construction, but there is still the 'Griffon' which has not been much reduced. Very great efforts should be made with the liners (upon which the pistons and rings so much depend) so that they may be hardened on the working surface. This has long been neglected because of the difficulties with austenitic liners, but we have now decided that we do not particularly wish for this alloy. (B) Regarding the pistons, I am pleased to see that you are attempting to get more surface to carry the load brought about by the angularity of the con. rods. I have lately suggested that even a small increase in the dia. of the piston pin will help to avoid the risk of the piston cracking. (C) Concerning con. rods, I was in hopes of hearing that we had definitely moved on to the articulated rods, for two reasons, one being the weakness at the feet of the forked rod, and the other the difficulty of putting Kelmit on the outside of the big end block. (I now understand that thanks to RHC{R. H. Coverley - Production Engineer}'s efforts the latter is no longer a difficulty.) Regarding the new suggestion of the curved end to the forked rod, in some ways this should help matters, but somehow I doubt whether it will prove a success. I agree however that it is worth trying, though I fear it is not very practical. You will remember we came to the conclusion at WW. about this rod that the heel to the foot was the cause of the weakness, and that it was brought about by an attempt at WW. to lighten the big end block. I suggested therefore that the joint should be carried further up, following more nearly the original design before the lightening is attempted. I do not think this has been adopted in DES. 1317. (HS.{Lord Ernest Hives - Chair} informs me that the clearance will not allow of this being done.) (D) With reference to controls, it has occurred to me that after the disastrous experience in connection with Miss England we ought to abandon some of these designs where they failed. It may be that the loads falling on those parts - being extremely difficult to estimate - may be higher than we think. In some ways I think HS.{Lord Ernest Hives - Chair} ought to make many experiments to find out if, under any circumstances, the throttle valve can jam in a closed position, after say a backfire, and cause the excessive load on the controls. To be candid I think that these parts require more study and testing, and better mechanical advantages as regards stress. I think an especial weakness would be found in the | ||