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).
Responding to an investigation into failures of Bentley & 20/25-HP engine gears.
| Identifier | ExFiles\Box 136\1\ scan0178 | |
| Date | 3rd February 1936 | |
| FJH{Fred J. Hardy - Chief Dev. Engineer} GRY{Shadwell Grylls} c. to RM{William Robotham - Chief Engineer}/HS.{Lord Ernest Hives - Chair} Sft{Mr Swift}/Sct.1/Na.{Mr Nadin}3.2.36. Re. Bentley & 20/25-HP. Engine Gears. Please note, your memo' RHC{R. H. Coverley - Production Engineer}/RHS/ETM.23.1.36., has been passed to us and we feel certain as a result of your investigations, steps will be taken to minimize, if not entirely eliminate those failings both of design and workmanship that militate against the production of the perfect and acceptable train of Engine Gears. Your suggestion for the Wheelcase to be ribbed internally, so that drumming may be eliminated, has however, been anticipated by the Design Department, for even now we are producing large bore Bentley engines which have Wheelcases so constructed. The weakness of the overhanging section of the Crankcase at the Dynamo Drive side we have always been aware of, hence the natural provision of a support during machining. You state in your memo' that the Crankcase has to be supported otherwise it would distort. We agree with this and, therefore, by supporting the overhang, we eliminate the need for making any allowances whatever. With regard to the Engine Gears, it is noted that you state that the 20/25 Cam Wheels are causing more trouble than the Bentley, apart from any deficiency of ours in the fitting of the cam, we would point out that the small bore Bentley was not fitted with the shrunk on type of cam, but with a solid cam bolted to the cam wheel. With the introduction of the large bore Bentley, however, we are fitting the shrunk on type cam as we are doing on the 20/25. With regard to the actual operations of fixing this cam we will examine all the points you raise. | ||