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).
Test report comparing pedal travel lost in the rear axle linkage of 40/50 and EAC.VII models, including measurements and calculations.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 124 | |
| Date | 28th January 1927 guessed | |
| contd :- -3- In order to determine the relative amount of pedal travel lost in the rear axle linkage on the 40/50 and EAC.VII cars, a test was carried out in which the brakes were brought into contact with the drum lightly, and then increasing loads applied at 'P', the movement of 'P' being measured after each increase in load. | Values of P. Initial load & required to bring the shoes in contact with the drum. | Resultant lost movement measured at P. | |---|---|---| | | EAC.VII. | 40/50 HP. | | 20 lbs. | -- | -- | | 200 lbs. | .555 | .341 | | 250 lbs. | .805 | .372 | | 300 lbs. | .981 | .403 | To convert to pedal movement, multiply deflection at P. by 14.0/5.875 X 1.7/2.5 = 1.625 It will be observed that the movement at the extremity of the lever on EAC.VII is .578 greater than that on the 40/50. It was suspected that this increase was due to drum distortion, and measurements were accordingly taken of the drum distortion on EAC.VII at the shoe centre under a load of 300 lbs. This was found to be .018" which is equivalent to - .018 X 4.5/.5 X 2/1 X 5.50/3.35 = .530" at point P. Assuming that the 40/50 drum distortion is negligible, this means that only .048" movement can be attributed to greater flexibility in EAC.VII shafts and mountings. contd :- | ||