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).
Goshawk II engine timing, comparing standard and proposed cam settings with diagrams.
| Identifier | WestWitteringFiles\K\July1923\ Scan16 | |
| Date | 12th July 1923 | |
| TO HS.{Lord Ernest Hives - Chair} FROM E.{Mr Elliott - Chief Engineer} ORIGINAL GOSHAWK 11. TIMING. Y3942 Referring to the diagrams of comparative timings you left at WW. particularly to the one giving the average timing for Goshawk 11. present standard, as follows:- [Diagram 1 - Left] Handwritten Note: Average GII timing E/I 12 7 ANGLE BETWEEN CAMS 117.25° 53/I 49/E [Diagram 2 - Right] E/I 5 12 .010 CLEARANCE ANGLE BETWEEN CAMS = 113.75° 49/I 39/E I cannot understand why this falls so far short of the diagram marked fig.3 on LeC.1044. which should be the correct timing with 10 m.{Mr Moon / Mr Moore} clearance. This particular timing is as follows:- [Diagram 3 - Bottom] E/I 16 10 .010 CLEARANCE ANGLE BETWEEN CAMS = 118° 54/I 54/E and is obtained with the use of the official valve lift curves - LeC.1048, and 1050. I find that if we attempt to produce a new exhaust cam to give the desired improved timing which is as follows:- (1) | ||