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).
Accelerometer road testing discussing instrument modifications and correlating results with physical sensation.
| Identifier | ExFiles\Box 138\2\ scan0044 | |
| Date | 1st July 1926 guessed | |
| -2- to enable us to carry out continuous tests more than 4 days without the points requiring attention. Whenever we clean up the points we have to re-set the accelerometer. We find it exceptionally difficult to reproduce the original setting. We find that the points are not so highly susceptible to slight oxidization if we increase the pressure between them. To do this it is necessary to increase the weight of the inertia element. We have temporarily carried this out by making the elements in our accelerometer out of a heavy lead antimony alloy. We feel however that for measuring accelerations of .3 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} and below, better results would be obtained with a larger inertia element of considerable weight, giving a high unit pressure between the points in its static position. Of the results we have obtained on the road, few seem to correspond with our own physical impressions. We find that if we place the accelerometers on the seat without cushions, they measure .3 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} accelerations as frequently as 30 times a second on quite a moderately good road. When we sit on the seat we cannot feel anything to correspond with this. On the other hand, some of the .3 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} accelerations which we record can be felt quite distinctly. There is no doubt that the amplitude has a marked effect on accelerations of this type. We find that when the instrument is held upon the knee of the passenger, people of different weight produce different record, this is only to be expected as they produce different cushion deflections, however, it adds yet contd :- | ||