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 analysis of engine cylinder head stud stress and design considerations.
| Identifier | ExFiles\Box 86\1\ scan0002 | |
| Date | 6th June 1932 guessed | |
| (2) | Engine. | Stud dia. | Stress at bottom of thread with max. cyl. press 500 lbs.sq" | Stress at bottom of thread with 1000 lbs sq" press: | |---|---|---|---| | P.II. | .375. | 17.000 | | | 20/25. | .312. | 14.250. | | | J.3. | .312. | 15.800. | | | Bensport & Peregrine. | .250. | 16.600. | 33.200. | | -do- | .312. | 10.450. | 20.900. | We have looked into the question of using less studs than six per cylinder, but we cannot find up till now any arrangement which suits us, and we are loath to depart from the Rolls-Royce 6 stud arrangement which has proved to be excellent for making a good detachable head joint. If we increase the diameter of the Bensport cylinder head stud from .25 to .312 it will demand an increase on the length of the engine of .3 with the present cylinder construction of inserted liners expanding the intermediate cylinder centres by .05". The centre cylinder distance is already .150" more than the others, and we should not propose to alter it. The present Peregrine Engine is really smaller in cylinder centres by .025" than it should be on a pro rata basis with J.3. We would, therefore, rather favour this slight increase in length than otherwise, as it would be appreciated on the crankshaft bearings since this smaller engine will naturally run faster. This amount of increase additionally also would allow of the larger bosses necessary for the cylinder studs without reducing the gas passages already arranged, and we believe it could be accommodated in the chassis layout without any trouble. E.{Mr Elliott - Chief Engineer} | ||