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).
Crankshaft modifications and experiments for supercharging 6-cylinder Bentley engines.
| Identifier | ExFiles\Box 85\5\ scan0083 | |
| Date | 21th January 1935 | |
| To Sg.{Arthur F. Sidgreaves - MD} & Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Bn.{W.O. Bentley / Mr Barrington} X217 HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KW. 21.1.35. Crankshafts for 6-Cylinder Engines. In view of the remark in the last car meeting minutes that we may be pushed into the position of having to supercharge the existing Bentley, we attach a report by Gry.{Shadwell Grylls} which is a summary of the work we have been doing on crankshafts for the last two years. Briefly, the position is that if the short pin crankshaft and lightened flywheel successfully complete 15,000 miles in France, the critical speed of the engine will have been raised from 5,000 to 5,620 r.p.m. This really means that the unit can be run safely at 5,000 r.p.m. which we think is sufficient to enable it to be supercharged if this is found imperative. The experiments we have carried out with the 4-bearing crankshaft have indicated that even if the engine could be completely re-designed to make the best possible use of this arrangement, we should only gain about another 230 revs. We shall shortly be able to demonstrate a supercharged Bentley on the road. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||