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).
The flywheel teeth count for large bore units fitted with Borg & Beck clutches.
| Identifier | ExFiles\Box 129\2\ scan0076 | |
| Date | 3rd October 1935 | |
| To RHC.{R. H. Coverley - Production Engineer} X 1110 Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}24/KW.3.10.35. Borg & Beck Clutch. We think that as we are fitting these clutches to all large bore units, the flywheel should have 118 teeth for either 20/25 or Bentley. In all cases, therefore, these engines will have 20/25 geared starter motors. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||