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 on the 25/30 deturbulated cylinder head and its planned standardisation.
| Identifier | ExFiles\Box 103\4\ scan0180 | |
| Date | 4th November 1936 | |
| x579 Sg.{Arthur F. Sidgreaves - MD} from Rm.{William Robotham - Chief Engineer} Hs.{Lord Ernest Hives - Chair} c. to E.{Mr Elliott - Chief Engineer} c. to Ey. Rm{William Robotham - Chief Engineer}10/GR.{George Ratcliffe}4.11.36. 25/30 DETURBULATED CYLINDER HEAD. We have had further comparative tests carried out on 22-GV in France comparing the present standard head with the deturbulated cylinder head. From these, it appears that there may be a slight loss of performance picking on between 10 and 40 m.p.h.; at all higher speeds the deturbulated head gives superior performance, and, in addition, is not so rough, and is less liable to detonate. Under the circumstances, we are circulating a standardisation sheet to bring this on production, as soon as the existing material has been used up. Rm.{William Robotham - Chief Engineer} | ||