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).
Analysis of brake system options, including servos and cylinder sizes, for the 'Myth' model car.
| Identifier | ExFiles\Box 110\1\ scan0021 | |
| Date | 25th October 1940 | |
| -2- Ev.{Ivan Evernden - coachwork}1/JH.25.10.40. wrapping shoe is not possible and the two non-wrapping shoes are prohibited with existing master and wheel cylinders. The pipe line pressure fixed could be restored by using an increased size of wheel cylinder, and a corresponding increase in the diameter of the master cylinder to compensate for the heavier load on the piston applied by the servo plus foot pedal. Such a scheme is opposed to rationalisation, whilst a larger wheel cylinder may not go into the available space in the present drums. If by direct braking we can stop the smaller Myth models, only an increase of 10% in the braking is required to brake the larger models. The servo can provide this, plus what we have lost in wrapping on the shoes and reduced pedal pressure. The servo does nothing to help the inadequate shoe area and heat absorption power in return for its added cost and weight. One is inclined to feel that any addedcost and weight on the larger models, if it can be allowed, would best be used in providing larger and more efficient drums. We feel that in the heaviest Myth (24 cwts) we have not reached the size of car which makes a servo a necessity. Ev.{Ivan Evernden - coachwork} Attached Sketch. | ||