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).
Failure of a Peregrine crankshaft during testing and proposals for new dimensions.
| Identifier | ExFiles\Box 85\5\ scan0012 | |
| Date | 21th June 1932 | |
| X217 To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} EV.{Ivan Evernden - coachwork} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} 9/KT. 21.6.32 BENSPORT CRANKSHAFT. Our tests with the Peregrine crankshaft with no inertia on the nose except the fan pulley show the half speed period to be at 2700 r.p.m. After a very short run at 6200 the crankshaft broke. E.{Mr Elliott - Chief Engineer} has therefore asked for the calculated critical speeds with crankshafts of other dimensions. These are given in the accompanying table. It must be remembered that increasing the pin diameter increases also the inertia of the pins, big ends, and possibly balance weights. The figures for the suggested crankshafts are based on a figure of 5400 r.p.m. for Peregrine. It appears that with the maximum dimensions suggested by E.{Mr Elliott - Chief Engineer} a speed higher than 6200 r.p.m. cannot be obtained, and this will be lowered by the damper hub. The speed of our engine will be limited by the crankshaft and not by the valve gear, with either overhead camshaft or push rods. All the successful really high speed 6 cylinder engines use only 3 or 4 bearings in the crankshaft. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||