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).
Difficulties and solutions discussed with E.R.A's concerning their Girling brake layout.
| Identifier | ExFiles\Box 120\3\ scan0167 | |
| Date | 29th April 1935 | |
| X4456 To E.{Mr Elliott - Chief Engineer} c.c. to Da.{Bernard Day - Chassis Design} c.c. to By.{R.W. Bailey - Chief Engineer} c.c. to Hdy.{William Hardy} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}2/KW.29.4.35. Girling Brakes. We have been able to have a further discussion with Berthon of E.R.A's on their Girling brake layout. The difficulties they have met are (1) Insufficient front braking due to the front axle coming back under the braking forces, (2) Inefficiency of brakes after adjustment, (3) Front axle judders and (4) Brakes locking on. As regards (1) it would appear necessary in a system of very small sponge that the friction in the fore and aft compensation be small enough to allow compensation necessary due to axle movement. We know the Bentley axle comes back about .200" when braking, and that the rear brakes are self-servo-ing. Efficient compensation seems therefore very necessary. (2) Has been corrected by the latest type of adjustment as supplied by Girling to us. For (3) they had to reduce by 2½" the length of lining on the wrapping shoe and by now will have less than 90º arc of embrace. As regards (4), they have found interesting confirmation of what Girling told us, namely, that if we fixed the floating fulcrum the brakes would not free as the sideways load of the wedge is taken on the dry bearing of its housing and is not balanced between each shoe. During the Donington meeting one of the E.R.A. cars had a rear brake seize. This was freed by hitting the fulcrum which had jambed. It seems to us important to prevent this trouble happening, by giving the wedges roller bearings in their housings. A rear brake on 3-B-IV has locked on one occasion. To make sure that the fulcrum n ever sticks seems almost impossible. It is open to dirt and grit on both sides and never slides very freely. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||