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).
The results of two tests on a Peregrine cylinder head, comparing standard inlet valves with larger ones.
| Identifier | ExFiles\Box 1\8\ B001_X100 Engine Chassis-page210 | |
| Date | 29th July 1932 | |
| r 4027a To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to Rg.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/WJ.29.7.32. INLET VALVE DIAMETER. We have conducted two tests comparing the standard Peregrine cylinder head with one having inlet valves of the same dimensions as the exhaust valves. Curve Rm.{William Robotham - Chief Engineer}Pr.15 shews the results on a naturally aspirated engine and Curve Rm.{William Robotham - Chief Engineer}Pr.20 the result on the same engine supercharged to 7 1/2 lbs/sq.in. We think that the naturally aspirated curves can be taken as being correct as we have previously had confirmatory evidence, and we do now know that with the larger valves Peregrine has been below the average of our engines for low speed M.E.M. We shall have to confirm the supercharged figures, however, as owing to the rising induction pipe temperatures we get a falling off in power with anything but snap readings. We believe the results are sufficiently reliable to shew, however, that there is little or nothing to be gained in top H.P. by increasing the size of the inlet valve above 1.2" dia., and that for ordinary work such as "Peregrine" will be called upon to do our existing 25 HP. figure of 2.2 sq.ins. of inlet valve area/litre is a very excellent compromise with our latest camshafts and will help our low speed pulling power on the small unit. It will be remembered that the "R" engine figure is considerably below this. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Attached Rm.{William Robotham - Chief Engineer}Pr.15 and Rm.{William Robotham - Chief Engineer}Pr.20. | ||