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 of a 'Myth' cylinder head with exhaust and inlet ports on the near side.
| Identifier | ExFiles\Box 109\3\ scan0086 | |
| Date | 22th March 1941 | |
| 700 1030 To Rm.{William Robotham - Chief Engineer} from Jnr.{Charles L. Jenner} c. to Rm{William Robotham - Chief Engineer}/HH. Jnr.{Charles L. Jenner}1/SW.22.3.41. MYTH Cylinder Head with Exhaust & Inlet Ports on the Near Side. Herewith are the designs - PL.518 and PL.519, which completes all the work necessary for the cylinder block and head. I am treating the carburetter and hot spot as a separate issue. We look upon this head as experimental to get a figure of merit between water heating for the inlet pipe compared with exhaust gas heating. At the same time, since we know so little about the phenomenon of detonation and roughness, we have taken the opportunity of fitting another plug per cylinder situated in the squish area. This spark plug can be used as twin-firing, or as an alternative. There has been some difficulty in getting the necessary .6 length of spark jump at the plug terminals but this has been achieved only by making the exterior of the cylinder head less clean in shape, and in consequence more costly to produce. The cooling of the near side spark plugs is just about acceptable, the sand coreways are stout enough for a 4 cylinder casting, but some doubt exists whether they would be sufficiently robust if we contemplated making a 6 cylinder engine of the same dimensions. The studding of the cylinder block is completely re-arranged from the former designs, but this of course, only affects the top portion of the cylinder block. The 10 m/m sparking plug has proved a blessing. The job would have been impossible with the old 14 m/m plug. Jnr.{Charles L. Jenner} Originals to Rm{William Robotham - Chief Engineer}/HH. Prints to Rm{William Robotham - Chief Engineer}/HH. Jnr.{Charles L. Jenner} & Ashby. | ||