Improvements and outstanding issues with the 16-G-4, 25HP engine, including flywheel vibration, balance, and exhaust.
| Identifier | ExFiles\Box 5a\1\ 01-page152 | |
| Date | 1st May 1931 | |
| HS. {Lord Ernest Hives - Chair} ) FROM R. {Sir Henry Royce} BY. {R.W. Bailey - Chief Engineer} ) C. TO ST. {Capt. P. R. Strong} WOR. {Arthur Wormald - General Works Manager} C. TO HY. {Tom Haldenby - Plant Engineer} RHC. {R. H. Coverley - Production Engineer} X1990 R6/1428.5.31. 25HP. - ORIGINAL JAPAN(Experimental Engine) I. 16-G-4. has greatly improved, for which I give credit as follows: (1) The mounting - softer diabolo rubbers and torque dampers, much less rough from torque impulses etc. (2) Increase in power due to exhaust. (3) The balance weights-possibly some smoothness and increase in mechanical efficiency. Although the speed indicator has been corrected to reduce the reading the increase in power has maintained the reading, and 70 MPH. seems possible. W. says for speed the roof could be 5" lower, and we suggest a continental touring close coupled 4 seater saloon be made for demonstration. We shall struggle to get the flywheel steadier but one does not definitely feel it. We know the S balance weights are not quite as good as the S. - i.e. two halves for saving the bearings, and we think rather heavier ones should be tried on the 8 weight scheme until we get dangerously near the master period, but should not exceed the half crank, half big end, and quarter little end, and piston as a unit, and 4 units. I like the F. {Mr Friese} steering: it is very easy to see out and not too low for my figure. One thing is still very wrong, and that is the drumming exhaust. EV. {Ivan Evernden - coachwork} is sending you a complete scheme reminding you of several features we sent some time ago, and some new ones to bring it in line with P.2. - i.e. from expansion box and greater capacity main silencer with double internal tube. We must not have external jackets if at all possible. I think that what the flywheel vibration is felt more on the 25-F. {Mr Friese} is that the overhang is greater and one may not feel the couple, but only the out-of-balance due to the centre of gravity overhanging the bearing and becoming out of truth. The C.I. unit may be better while the bearing is a close fit but would soon become bell-mouthed and allow the flywheel to go. The amount the crank bends and go a long way when the period is right. We must not get the period up above 70 MPH. or lower it and steady up bearing on shaft - see special memo. R. {Sir Henry Royce} | ||
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).