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).
Performance, testing, and benefits of 'Razend Crown' pistons, proposed to be renamed 'Power Dome' pistons.
| Identifier | ExFiles\Box 148\1\ scan0110 | |
| Date | 20th April 1938 | |
| 1256. & Rm{William Robotham - Chief Engineer}'s Policy file Ry. from Rm.{William Robotham - Chief Engineer} C. Sg.{Arthur F. Sidgreaves - MD} C. Hs.{Lord Ernest Hives - Chair} C. Da.{Bernard Day - Chassis Design} C. RHC.{R. H. Coverley - Production Engineer} C. RFL. C. Wx. C. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} S. Da{Bernard Day - Chassis Design}/Jod. Rm{William Robotham - Chief Engineer}/1/20.4.38. RAZEND CROWN PISTONS. In future, it is proposed to call these "Power Dome" pistons. They have run - 17,000 miles on G.S.V. at 6½-1 32,000 " " " 7½-1 In addition, they did the work on Fabiricesco' car at 6.8-1 and have run 100 hours on the test bed. They are now fitted to seven experimental cars. So far we have had no trouble at all with them, the oil consumption of G.S.V. at the conclusion of its run being over 3,000 M.P.G. It will be impossible to assess the true value of this type of piston until it has been tried out in production under every type of climatic condition in customers' hands. We believe that a conservative estimate from our own tests is that it permits an increase of ½ a compression ratio for a given degree of detonation. Apart from this, it has the undoubted asset of enabling different compression ratios to be used on any given engine by changing the piston only, and not the cylinder head as hitherto. It is proposed to standardise them on B.V. Rm.{William Robotham - Chief Engineer} | ||