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 changes to the 10 HP Myth Cylinder Head, superseding a previous design.
| Identifier | ExFiles\Box 110\2\ scan0071 | |
| Date | 17th September 1940 | |
| 103R. File Myth 719 To Rm.{William Robotham - Chief Engineer} c. to Rm{William Robotham - Chief Engineer}/HH. Jnr.{Charles L. Jenner}1/JH.17.9.40. 10 H.P. Myth Cylinder Head. We send herewith PL.341. This design supersedes the cylinder head PL.325 as it now has been decided that the "original" shape of combustion chamber is less rough compared with the "intermediate head" as referred to in memo. Rm.{William Robotham - Chief Engineer}17/ML.9.9.40. At the same time we have embodied in the design a shape of inlet port which should have improved volumetric efficiency and a valve seat with diffuser action. Also the inlet valve head has been increased in diameter. There is no alteration to the cylinder stud spacing or water ways, the major modification is raising the rocker cover and pedestal facings. There is no alteration to the geometry of the valve operation and the length of push rods and valves are the same as the previous design. In doing this the length of the distributor drive shaft is increased. The size of the throat is given on the drawing, it should be adequate in size even for the 8 H.P. engine which is .103 shallower with a 7 - 1 compression ratio. Because we have particulars, we have shown a standard thermometer fitted at the rear end of the head, but it is intended to use the bi-metal strip instrument with electric recording and the same boss will most likely be suitable, will you please investigate. Jnr.{Charles L. Jenner} Original to Rm{William Robotham - Chief Engineer}/HH. prints to Rm.{William Robotham - Chief Engineer} Ev.{Ivan Evernden - coachwork} Ashby. Olley. | ||