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).
Design considerations for cylinder end studs, valve rocker cover, and sparking plug holes.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan295 | |
| Date | 2nd May 1931 guessed | |
| (2) ORIGINAL may not be permissible on the question of cost. (3) CYLINDER END STUDS. The question of whether the end studs A.{Mr Adams} and B. should run through to the crankchamber was mentioned in our previous memo. The dia. of the cyl. studs is the same as on the 25HP. - e.g. .312 and the stress with a pressure loading of 600 lbs. per sq. in. in the cyl. is 20,500 lbs. per sq. in., the same as P. 2. studs, assuming that 6 studs are taking the load of 1 cyl. With 4 studs only carrying the same load the stress is 30,000lbs. This stress is only equivalent to 23 lbs. on the end of a six inch leverage on the nut assuming the usual efficiency of 8%, and therefore about half the expected stress due to initial tightening. We cannot see that the side end studs would get any more loading than this even without A.{Mr Adams} & B. running through, even though they are on the ends of the beam without the continuity of the section to help them. (4) VALVE ROCKER COVER. Since sending the print of LeC.2853. we have removed the re-entrant features from the valve rocker cover with a view to this part being die cast. We have been enabled to do this by having a little more room in the design generally. The present cover is a sand casting machined inside the lip as well as round the joint face. We might possibly avoid machining with a die casting altogether. (5) SPARKING PLUG HOLES. We hope to coax the sparking plug holes a little lower in the head so as to arrange the drilling and tapping clear of the cylinder crown. E.{Mr Elliott - Chief Engineer} | ||