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).
Predicting the relative severity of 6th order torsional vibration on a Phantom II engine compared to a 60 Vee 6250cc engine.
| Identifier | ExFiles\Box 179\2\ img278 | |
| Date | 24th February 1932 | |
| ORIGINAL R.{Sir Henry Royce} From HS{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to E.{Mr Elliott - Chief Engineer} c. to Rs.{Sir Henry Royce's Secretary} TORSIONAL VIBRATIONS. X634 E.{Mr Elliott - Chief Engineer} has asked for a prediction of the relative severity of the 6th. order vibration on P.II and a 60 Vee 6250 cc. engine. That is of course a comparison of the Phantom half period and the 12 cylinder top period. Assuming the same indicator diagram in each case the period on the 12 cylinder should be 5/6 of the magnitude of that on P.II. This is true for any firing order of the Vee engine. A GGO engine would be a negligible improvement. Lincoln employ an unusual firing order namely :- 1 <-> 5 <-> 3 <-> 6 <-> 2 <-> 4 <-> 1 For the 6th. order vibration this has no effect on the magnitude of the vibration. It is true to say that the magnitude of the nth order vibration of an a throw crankshaft engine is independent of the firing order. Other vibrations are however affected. Hs{Lord Ernest Hives - Chair}/H.Grylls. | ||