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).
Comparative tests between the Large Inlet Valve Head and the Standard Head for the 8 Litre Phantom engine.
| Identifier | ExFiles\Box 17\6\ Scan162 | |
| Date | 28th September 1933 | |
| x7030 To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell} c. Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}12/KT.28.9.33. x7771 8 LITRE PHANTOM. Comparative tests between the Large Inlet Valve Head (E.83906) and the Standard Head (E.83538). The respective throat diameters of the large (E.83904) and standard valves (E.82458) are 2.00" and 1.9", the areas being 3.0 sq.in. and 2.69 sq.in. From tests carried out with the original large valves (E.83904) it was found that even when using the strongest springs available, valve bounce occurred before 3500 R.P.M. By modifications (Lec.3599) and (Ex.12011) the weight of the valve was reduced from 6.53 ozs. to 5.32 ozs. so that we were able to run up to 3500 R.P.M. free from valve bounce. This we verified by the fact that substituting Hs.{Lord Ernest Hives - Chair}664/5 for the stronger springs gave no reduction in power at 3500 R.P.M. The average of several comparative tests taken between the large and standard valves are shown on the curve Hs.{Lord Ernest Hives - Chair}1147, there being a very small power increase, 2 - 3 H.P., with the large valves at speeds above 3000 R.P.M. This can be almost disregarded, as it is impractical to obtain results to within 1% at the peak power speeds, even when running under the same conditions. Below 1000 R.P.M. the standard valves are 2 - 3 lbs. M.E.P. above the large valve figure, and at speeds between 1000 R.P.M. and 3000 R.P.M. the results are almost identical. From tests by Hs{Lord Ernest Hives - Chair}/Std. on the air flow through the valves it was expected that the large valves would give a 2.1% increase in power at the maximum speeds or 4 - 5 H.P. Hs.{Lord Ernest Hives - Chair}1147 also shows a curve taken with the exhaust valves used as the inlet valves, that is 1.700" throat. Confirming the air flow tests this figure is 4.5% or 9 H.P. lower than with the standard valves at the maximum speeds. Below 1500 R.P.M. there is no difference in the results. Hs{Lord Ernest Hives - Chair}/L.H.Swindell. | ||