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).
Goshawk 11 engine vibration, its potential causes and solutions.
| Identifier | ExFiles\Box 74\3\ scan0258 | |
| Date | 18th February 1922 | |
| X4221 To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to CJ c. to Wor.{Arthur Wormald - General Works Manager} c. to BY.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} R1/M18.2.22. GOSHAWK 11. ENGINE VIBRATION. X.4221. With reference to your Hs{Lord Ernest Hives - Chair}1/LG16.2.22., is the crank-chamber bending in its length, if so it can only bend sideways by deflecting the nearly vertical walls. It looks as though such a deflection would be proportionate to the square of the speed, and that it might strike a period at this 3,000 odd revs. and then build up to anything. If this is the trouble we must strengthen the crankchamber, to raise the period out of danger zone. But make sure that it is this kind of vibration. I was beginning to think it was the hunting of the spring drive due to intermittent firing when the valves left their seats; this would have been proved by increased valve springs altering or otherwise the speed at which these vibrations occur, and also by increasing the damping of the spring drive. Your experiment of belt drive suggests that it is not explosions at all: (with and without bottom half should make a difference.) Goshawk 1. is different in the crankchamber, carried on an underframe, and it was shorter also, so the period of this may be higher and out of reach. The simple bending of the crankchamber could be reduced by lightening the crank pins and webs: (as Goshawk 1) balance weight contd:- | ||