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).
Laborious operation of brake pedals and suggesting design modifications for various models.
| Identifier | ExFiles\Box 147\5\ scan0266 | |
| Date | 16th June 1938 | |
| [Handwritten]: 635 [Redacted]: Sy. Rm.{William Robotham - Chief Engineer} [Redacted]: Chief Designer c. Rm.{William Robotham - Chief Engineer} Da{Bernard Day - Chassis Design}/Hdy.{William Hardy}10/G.16.6.38. [Handwritten]: A.F.T. [Handwritten]: Should like your Comments Rm{William Robotham - Chief Engineer} BRAKE PEDALS. When driving 24-G-V1. last weekend, I found that the operation of changing my foot from the brake to the accelerator and vice versa was much more laborious than it should be in view of the frequency with which this movement is made. The difference in height on 24-G-V1. is about 2 3/8". The designed amount for Wraith is 2 1/4", 25/30 has only 1/2", Bentley 111 has 1 1/2". As far as I can see the difference between the Wraith and the 25/30 has come about from two causes, namely :- (1). An increase of nearly 1.0" is called for by our brake design N. schemes. (2). It appears that 1" has been allowed for matting under the brake pedal plate, which has not been allowed on the 25/30 and which is also not now allowed on the accelerator pedal of the Wraith. As regards (1) there is an allowance of 1/4" extra travel compared with the 25/30 to prevent the brake pedal descending on to floorboard in the event of a failure of the system. The remaining 1/4" of extra travel was provided to compensate for the much higher direct leverage on the Wraith compared with the 25/30 i.e. [Handwritten: 24] instead of 17:1. I suggest that it should be determined whether we can reduce the designed pedal travel by 1/2" and the allowance for matting by 1/2" and thus reduce the difference in pedal height to 1 1/4". With this difference the movement of the foot can be made without lifting the heel off the board, whereas with 2 1/4" difference I found it impossible to avoid lifting my foot. I understand that the accelerator pedal was recently dropped 1 1/4" as the result of a complaint by Sg.{Arthur F. Sidgreaves - MD} and therefore it seems inadvisable to raise this by even 1/2" unless the coachwork is modified accordingly. It seems to me that in new designs it would be possible to further reduce the difference in height of the pedalsby pocketing the brake pedal plate in the floorboard | ||