Rolls-Royce Archives
         « Prev  Box Series  Next »        

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 methodology for measuring vehicle speed and acceleration over specific time periods.

Identifier  ExFiles\Box 113\2\  scan0169
Date  11th November 1930 guessed
  
-5-

The duration of the 1st M.P. can vary between zero and one second, for it depends on the position of the escapement at the moment when measurement begins. In order to reduce this error to a minimum, we recommend that the 1st M.P. should be based on ½ second. If, from B, we drop a vertical on the zero line, we get a point C. The distance A-C is proportional to the distance traversed during the first measurement period, and since 2 m/m = 1 metre the distance in metres -

length A-C in m/m = 2.2 / 2 = 1.1 metres.

At the moment when the first measuring mechanism is held (point B), a second mechanism comes into action, and is raised from the point C. As the speed has increased, it attains, at the end of the second M.P. a height greater than that of the preceding mechanism. In fig. 5, the elevation of the second mechanism is represented by the line C-D and we see that the horizontal line after the point B rises obliquely immediately this measuring mechanism rises higher than the preceding one. If we drop a vertical on the zero line, we obtain the point E.{Mr Elliott - Chief Engineer} The distance A-E corresponds to the two first measurement periods, the distance C-E to the second measurement period only. The duration of the second and of all the following measurement periods is now always one second. At the point D.{John DeLooze - Company Secretary} the end of the 2nd M.P., the 3rd measurement period thus commences to the point S, and so on until the maximum speed is attained. In fig. 5, this moment is attained at the point F, or after the 17th M.P., from the fact that the following M.P., presents no acceleration, the height attained remaining the same as that of the 17th M.P. The diagram shows us that the 17th M.P. is the last which presents any acceleration. We cannot determine at what point of this 17th M.P. the maximum speed has been attained. To reduce the error, this last M.P. must, therefore, like the 1st M.P. be only counted as a half, i.e. ½ a second. The distance traversed by the vehicle to attain the maximum speed is represented by the
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙