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 analysis of engine design features and issues from various manufacturers.
| Identifier | ExFiles\Box 133\3\ scan0037 | |
| Date | 27th February 1939 | |
| - 2 - The width of the shroud is 1". We had thought that the spiral swirl from the four nozzle holes was a desirable feature, but this proves to be an artist's imagination. A.E.C. do get valves remaining open, in which case they are shut by the piston, which sometimes results in the short tappet rod becoming bent or broken. A.E.C's opinion is that the best nozzles are made by Bosch, but Sims make the best pumps. They thought the Saurer patent nozzle was the finest. Whether it is turbulence head or direct injection, they are in trouble with piston land wear. This is really acute, because they have gone to cast-in steel inserts for the two upper rings. Although A.E.C. are all for the direct injection they say that for small bores the turbulence type is easier to design. We notice that they have no crankshaft torsional damper, and that the auxiliaries were driven by a twin roller chain. The reason for driving the fan by a chain is because they have not found a satisfactory belt to transmit high H.P. and running at 1.6 ratio. They can not make a nitrided crankshaft, and are using the 'Tocco' process. They are suffering from broken shafts in the webs at the middle cylinders. Mr. Robinson, their Chief Designer, had a poor opinion of the MAN. type of engine. It is essentially a slow speed engine. He thought the Lanova was wrong in principle, and quoted that Dennis had abandoned the Lanova and were adopting direct injection, but up to the present they had failed to make this engine good, and were now forced to use Gardner power units. A.E.C. have tried aluminium cylinder heads,/they distorted due to heat, it may be /but this was due to the system of bolting, since it was the same as the cast iron head. They have had no experience with blowers of any type. | ||