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).
From the USA discussing variable speed fans, bearing materials, and methods to prevent drivetrain chunking.
| Identifier | ExFiles\Box 173\4\ img095 | |
| Date | 6th December 1935 | |
| USA To MG. c. to Mor. c. to K.{Mr Kilner} c. to By.{R.W. Bailey - Chief Engineer} c. to Hdy.{William Hardy} HM{Capt. W. Hallam - Head Repairs}/R.{Sir Henry Royce}/W/KW.6.12.35. The following is a copy of a memo. received from Hm{Capt. W. Hallam - Head Repairs}/Gry.{Shadwell Grylls} in the U.S.A. dated 25th November :- "With regard to variable speed fans, this is carried out by a centrifugal bob weight which causes the effective diameter of the pulley to vary, the halves of the crank pulley which are sprung together alter in size to keep the V belt tight. Non-one uses variable pitch fans. To-day I went to Graham-Paige's, which compared to the G.M. organisation was like Jowett to R.R. I discovered from Kishline - (1) They have successfully used Cadmium Silver for 18 months and say it prevents higher oil temperatures than whitemetal. Fortunately Ribbingall of G.M. research walked in to dinner and without divulging the source of my information I asked him about this. His reply was that no doubt their whitemetal bearings lasted forever - to some extent true as Kishline talked about 40,000 miles. They are made by Federal Mogul in Detroit, and I will go and see these people. (2) As regards chunking they have found - (a) There is a critical flywheel inertia necessary to prevent this trouble, varying for different chassis. A small increase arriving at the critical amount may cure the job, although a large increase before that has done no good. (b) If a light flywheel is necessary for other reasons plenty of slack in the prop. shaft splines might help. (c) Damping acoustically the prop. shaft by tape winding or internal cork inserts helps. | ||