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).
Test results and further development of a high power cylinder head.
| Identifier | ExFiles\Box 134\2\ scan0002 | |
| Date | 7th January 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Wd.{Mr Wood/Mr Whitehead} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}16/KW.7.1.35. High Power Cylinder Head. The results obtained by this cylinder head seem to be very interesting. We do not like it being so critical to the ignition advance and would suggest that you produce a curve such as we usually use for car engines, showing the variations in ignition timing which can be used to give 5% drop in power either side of the best setting. The next step would be to open out the transfer passage to reduce the amount of turbulence. We should anticipate that with the double inlet valves less forced turbulence would be required to give freedom from detonation and a good low speed M.E.P., but you will of course shortly be able to try this out. Beal of Ricardo's was saying that the shape of the edges of the transfer passage made a considerable difference to the amount of turbulence imparted to the charge. We do feel that in order to get the best out of this head now that it has shown such initial promise, it would be worth getting a number of cylinder head castings that can be machined to give different transfer passage areas, and also experiment with a high compression head of, say, 9 to 1 of this type, so that we can get the whole story before being committed. We feel apprehensive that if we are any better for detonation than the standard head, the resultant engine will be too sensitive to ignition advance and too critical with regard to ignition to be a very good production proposition. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||