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).
Results of using accelerometers to measure riding comfort and discomfort levels for the Phantom suspension.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan026 | |
| Date | 15th July 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Oy. c. to PN.{Mr Northey} CWB. ORIGINAL PHANTOM SUSPENSION. X8410 X235 We have spent a certain amount of time trying to evolve a satisfactory instrument for measuring riding comfort. We have made a number of contact accelerometers of a type for which great things were claimed in the States. So far, in spite of a large number of tests, these instruments have not proved successful. We can measure big differences which can be detected the moment one steps in the car, but otherwise results are unreliable. They have, however, given us some indication of the accelerations which cause discomfort. Considering road speeds between 20 and 30 M.P.H., we find the accelerations of .2 g.{Mr Griffiths - Chief Accountant / Mr Gnapp}, if measured by holding the instrument on the passenger's knee, are detectable but not unpleasant. .3 g.{Mr Griffiths - Chief Accountant / Mr Gnapp} may or may not cause slight discomfort. If the accelerations are measured by placing the instrument on the boards, far more .3 g's are recorded than can be felt by the passenger also sitting on the boards. Therefore with accelerometers, cushions have to be used to read accelerations felt by the passenger, which increases the variables. .4 g.{Mr Griffiths - Chief Accountant / Mr Gnapp} is definitely uncomfortable considered from the luxury car point of view. .5 g.{Mr Griffiths - Chief Accountant / Mr Gnapp} is the sort of acceleration we measured in the back of the car going over any normal sharp edged pot-hole with tyres at 45 lbs/sq.". If we let the tyres down to 25 lbs/sq." we can cut most of the .5 g.{Mr Griffiths - Chief Accountant / Mr Gnapp} out Contd. | ||