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).
Continued technical comparison of engine balance between straight-eight and six-cylinder engines.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 3 | |
| Date | 6th December 1926 guessed | |
| contd :- -2- extra air valve (such as the latest Stromberg) and give a beautifully regular and dependable low speed performance (probably at the expense of very rich mixture). Possibly the size (etc.) of the manifold is responsible. (6) There is a theoretical out-of-balance in the straight eight which is nearly 100 times as large as the six. At 2000 revs. and with proportions of the Silver Ghost engine, the out of balance of an eight reaches 31 lbs. max. at a frequency of 4 times engine speed, whereas the six reaches .36 lbs. max. at 6 times engine speed. Since our ounce error in a piston will give about 21 lbs. max. unbalance force at the same speed, the straight eight error does not seem to be of any importance. But it occurs at firing frequency, and might cause humming and buzzing in the car which would be attributed to exhaust noise. The latest Packard eight is a very excellent car in many ways. Hs.{Lord Ernest Hives - Chair} | ||