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 from Frank B. Halford discussing proposed modifications to a hydraulic rocker and push rod to increase engine RPM.
| Identifier | ExFiles\Box 88\4\ scan0094 | |
| Date | 1st August 1934 | |
| FRANK B. HALFORD, F.R.Ae.S. DESIGNER OF AERO AND AUTOMOBILE ENGINES. Telephone Nos.: Gerrard 1217. Gerrard 1218. 8 & 9 GOLDEN SQUARE, LONDON, W.1. My Ref. FBH/EA Your Ref. Hs{Lord Ernest Hives - Chair}/Smth 24/KW. (Expt. Dept.) 1st. August 1934. Messrs. Rolls Royce, Ltd., Derby. Dear Sirs, I now enclose two blue prints off my Drawing No. SK4394 which indicates in general-arrangement form the modifications I suggest, incorporating the hydraulic rocker, and enabling the engine to be run above 5,000 r.p.m. without valve bounce. Although the proposals are fairly completely shown, it might be as well for me to mention the following points:- (I). Rocker Assembly. So far, I have only endeavoured to lighten the hydraulic unit and its fixing. On receipt of the present hydraulic rocker detail and the maximum positive acceleration figure, I should like to stress the rocker with a view to seeing how far its equivalent weight can be further reduced with safety. This latter step, however, is unnecessary if a maximum speed of only 5,000 r.p.m. is required. You will note that I have provided an air "bleed" hole. It might be desirable to heat the rockers to obtain the necessary shrink fit of the inner member of the unit, to prevent the latter distorting. For the same reason nitriding might prove preferable to case-hardeneing for the wearing surfaces of the unit. (II) Push Rod. On further consideration I think it would be desirable to stick to steel rather than change over to a light alloy tube. The push-rod return spring can easily take care of any slight additional weight; a solid steel rod is more reliable in production and it certainly lends itself better to the anchorage of return springs in the space available. | ||