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).
Technical explanation of static and dynamic wheel balancing.
| Identifier | ExFiles\Box 29\1\ Scan116 | |
| Date | 8th October 1925 guessed | |
| contd :- -19- H.{Arthur M. Hanbury - Head Complaints} OUT OF BALANCE OF THE WHEELS. There are two sorts of out-of-balance :- (a) Static out of balance which can be easily observed and suppressed. (b) Dynamic out of balance which is more difficult to ascertain and eliminate. We designate a wheel out of balance statically when being suspended freely on its hub, its plane being vertical, it tends to take up a position of stable equilibrium such that its centre of gravity is as low as possible, since it does not coincide with the axis of rotation of the hub. A wheel is, on the contrary, balanced statically when, no matter what its position relative to the axis of the hub may be, it is in equilibrium. That is, its centre of gravity coincides with the axis of the hub. In garages, static equilibrium is restored in the following manner. The vertical diameter of the wheel when it is in its position of stable equilibrium is brought into a horizontal position. A weight P. is then applied diametrically opposite to the out of balance on the rim so that if one calls the out of balance m, d₁ and d₂, the distance of their centres of gravity from the centre of the hub, one has - mgd₁ = P. d₂ When the wheel turns rapidly, the centrifugal forces applied to the corresponding centres of gravity have for expression m w² d₁ and P/g w² d₂ and we have contd :- | ||