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).
Page explaining the function and data interpretation of a fifth wheel drive and accelerometer for vehicle testing.
| Identifier | ExFiles\Box 113\2\ scan0168 | |
| Date | 11th November 1930 guessed | |
| -4- A fifth wheel drive has been specially designed for the drive of the instrument on automobiles (Fig. 4). This device is composed of a fixing bracket forming a bearing around which pivots a frame carrying a bicycle wheel. The fixing bracket allows the device to be mounted on the left or right hand running board of any car. The rotation of the wheel is transmitted by chain gearing and flexible shaft to the instrument spindle. The whole is very simply fitted. Graduations. The following are standard - 30, 60, 90, 120, 150 and 180 kms., or miles per hour for a forward feed of the chart of 1,000 or 2,000 m/m per kilometre or mile and 1,200, 2,400, 3,000, 3,500, 4,800 or 6,000 revolutions per minute for a forward feed of the chart of 500 or 1,000 m/m per 1,000 revolutions. If desired the instrument can be arranged for other graduations and paper feeds to be determined for each particular case. Diagram. Fig. 5 is the reproduction of a diagram as obtained in practice by means of an accelerometer graduated to 90 kms. per hour, and having a paper feed of 2 m/m per metre. On the zero and 90 km. per hour lines will be seen the punctures spaced at 3 m/m, of the feed roller, allowing the distance traversed to be determined. 2 millimetres below the 90 km. line there is a double puncture every 60 m/m.{Mr Moon / Mr Moore} a) Acceleration - Acceleration has commenced at the point A, i.e. from starting and is represented by the stepped diagram. The horizontal line at the point B corresponds to the end of the first measurement period (1st M.P.) and the length of the horizontal line corresponds to the time during which the first measuring mechanism has been maintained in position. The height of the point B above the zero line corresponds to the average speed of the vehicle during the first period of measurement (1st M.P.). It is read direct or can be calculated as follows.- height above zero line in m/m 2.8 m/m maximum height recorded in m/m 60 m/m maximum graduation in Km.per hour 90 km. (2.8 m/m / 60 m/m) x 90 = 4.2 km. per hour | ||