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).
Proposal for a new inlet cam form submitted for criticism, detailing changes to acceleration and engine timing.
| Identifier | ExFiles\Box 43\3\ Scan127 | |
| Date | 10th February 1927 | |
| To R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} X4003 E1/10.2.27. c. to BJ. LRG. YHS. DIRECTOR OF EXPERIMENTAL DEPT. Re. F.10. CAM FORMS. X.4003 X.3822 We send you herewith print of inlet cam form - Lec.2378 - shewing the first proposal that is being submitted for criticism to the committee, based on your memos. SHARP ACCELERATION. The sharp accelerations have been increased in value taking advantage of the larger pad radius to improve the cam form, and to assist in keeping the deceleration down in the first half of the cam. The shortening of the first half of the cam would otherwise have the effect of forcing up the deceleration. This sharp acceleration shewn for the first half is now 10% more than on the present RR. F.10. exhaust cam, and is the same as used on the Phantom inlet cam. The rocker bar load will be increased by this, and by the proportions of the rocker to about 50% more than at present, but there is some relief in the revised plan of the levers. ENGINE TIMING. Engine timing remains unaltered as this inlet curve is same length as present one -SCH.797. EXHAUST CAM. The proposed exhaust cam would be symmetrical and would be like present cam - sch.795 - but with slightly increased sharp accelerations. MINOR ACCELERATION. You will notice the compensation for friction and pressure on the inlet valve arranged as per your sch. which amounts to about 10 lbs. actual on the closing side of the cam. Only the figures necessary for getting some idea of the shape of the curve etc. have been worked out. The remainder can be completed at Derby when it is decided to go ahead. E.{Mr Elliott - Chief Engineer} (signed) | ||