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).
Analysis of a howling side shaft, calculating vibration frequencies based on engine speed and gear teeth.
| Identifier | ExFiles\Box 75\1\ scan0003 | |
| Date | 24th January 1911 | |
| R.R. 300 (6 B) (W. 159. 24.1.11) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1411. ROLLS-ROYCE LIMITED. INSTRUCTIONS. 511 19 To Order No. Customer's No. Re Howling Side Shafts Cont. For instance, a certain sideshaft was loudest on the notes (about) G to C (middle C of piano) when the engine speeds were 400 to 450 per minute. Note A (intermediate) is given by about 217 vibrations per second. We have (400 revs) x 30 (teeth on side) / 60 (seconds) = 200 450 x 30 / 60 = 225. This result would of course be expected. But the note given is a musical one whereas the teeth would produce merely an even noise. Evidently therefore there is something in the box [text struck through]. Signed This Sheet must be filed on completion of the work. | ||