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).
The methodology for tests to determine the centre of gravity for various car types.
| Identifier | WestWitteringFiles\K\June1923\ Scan61 | |
| Date | 31th May 1925 | |
| TESTS TO DETERMINE POSITION OF CENTRE OF GRAVITY OF VARIOUS TYPES OF CAR. We originally intended to carry out these tests by jacking the car up on, say, the off-side, placing the wheels on blocks of equal height, finding the consequent weight on the near-side track, repeating this at various heights and so calculating the height of the centre of gravity from the ground. We abandoned this because the irregularity of the ground in the immediate vicinity of the only large weigh-bridge, made it impossible to ensure the height of the blocks being absolutely the same, also the difficulty of gating a repetition of readings to correspond. We then decided to turn the car about the off-side track until it was on the point of falling over, to balance it there, measure the height of the near-side track above the ground and so calculate the exact angle at which the car balanced, hence the height of centre of gravity above the ground. We did this with 3-Goshawk-ll and 7-Goshawk-ll, when it at once became apparent that we were going to get very small differences. We also found it unsatisfactory balancing the car on the tyres, as at 45º there was a very large area of contact, and unless the tyres were inflated to exactly the same pressure, errors obviously occurred. We therefore removed the tyres and balanced the car on the rims. We found we could then balance the car and obtain measurement as to the height of the near-side rims above the ground to within a thirty-second of an inch. contd:- | ||