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).
Method for determining the position of piston knock using a stroboscopic telephone.
| Identifier | ExFiles\Box 35\2\ scan 152 | |
| Date | 11th October 1919 | |
| To Bn.{W.O. Bentley / Mr Barrington} from EFC. c. to EH. c. to Da.{Bernard Day - Chassis Design} x.2748 370H RE METHOD OF DETERMINATION OF POSITION OF PISTON KNOCK IN CYCLE BY MEANS OF STROBOSCOPIC TELEPHONE We have experimented with a view to determining the right method to use for this purpose, and we have arrived at the following :- We cannot find any means of getting rid of the click due to the opening and closing of the synchronised contact, but matters can be arranged by placing the microphone in parallel with the contact breaker instead of in series and making the period of make very small, such that the circuit is quite normal until the contact makes and so produces the click in the telephone. The point is this, that if we can hear the piston knock in the telephone at all, then by producing another timed click by means of a contact made by the contact breaker, we can vary the instant of this click until it synchronises with the piston knock. We shall then be able to say that the instant of piston knock is the same as the instant of contact. For this purpose we can use a standard make and break, except that the cam for this should have only one of the six flats. We shall then be able to produce one instant only of make per two engine revolutions which is what we require for this purpose. The Experimental Dept. have already prepared a cam like this. EFC. W W' RIPPON (300 8/10/19 SOW SP{Mr Spinney}/141) NEW DERBY | ||