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).
Chassis periodicity issues and suggesting improvements for the 'SS' engine mounting.
| Identifier | ExFiles\Box 14\5\ Scan089 | |
| Date | 4th March 1929 | |
| x7505 To Hs.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} To E.{Mr Elliott - Chief Engineer} } LE CANADELHenry Royce's French residence. To DA.{Bernard Day - Chassis Design} } c. to BY Wor.{Arthur Wormald - General Works Manager} c. to PN.{Mr Northey} CWB. Copy of written note 4.3.29. R2/LGS.3.29. 'SS{S. Smith}' ENGINE MOUNTING. I believe that the front end of every chassis will have a period such as we are experiencing trouble from. Every axle with given tyres etc. will also have a period. Both these can be found on the bumping rig possibly needing more than one block per rev. and also sometimes may need the blocks in effect on the wheels. Two things seem possible (1) is that the periodicity of one shall not be the same as the other (which struck me at once was our trouble) - (2) is as much damping as possible should be applied to the parts. Our next point is that we have to avoid the engine torque reactions from reaching the frame so that we have not a free hand in the use of the engine as part of the structure. I am suggesting here that we find the periodicity of the frame front end and if we can make this out of step with the axle, which I believe is generally understood to be between 600 and 700 per minute, we cannot expect to do much more. I am also suggesting that we test the value of an elastic vertical suspension (horizontal rubber), and instead of rubber on the vertical sides of the frame, we fit brake lining material, spring load the surfaces so as to contd :- | ||