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).
Performance, noise issues, and potential modifications for Bentley Aluminium brake drums.
| Identifier | ExFiles\Box 146\2\ scan0093 | |
| Date | 3rd February 1937 | |
| [Handwritten top left: 12 u 5] [Handwritten top right: Sr3/Crn.3.2.37.] [Handwritten top right: MARTINDALE : File] Bentley Motors (1931) Ltd., DERBY..................Rm.{William Robotham - Chief Engineer} Bentley Aluminium brake drums. ----------------------------- In answer to your memo. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}I/AP.I.2.37, the position with these brake drums at the present moment is that they have [strikethrough: been fitted] to my car - B. 8 GA - [handwritten: with] the standard [strikethrough: servo cams.] [handwritten above: have been] fitted. Why, I am going to investigate. As previously mentioned on the 'phone, I find the braking on this car, as it is, very effecient, although I must admit that the best braking is obtained at high speeds. At this moment, the effort on the foot brake appears to be normal, whereas the braking effect is much more positive than with the standard brake drums. By this, I mean that the car seems to pull up in a more "one piece motor car manner", there being no tendency for the front to "jelly". On the other hand, a exceedingly disagreeable crackling noise (bell tinkling noise) has developed, principally on the right front brake drum. This is particularly annoying, and kicks up what I should like to call for a brake drum a "hell of a din" everytime the brakes are applied, even ever so slightly. I have also observed that the amount of effort that one has to apply to the brake pedal to pull up the car at slow speeds, by this I mean 60 m.p.h. downwards, is considerably greater than the effort necessary on a standard car. In spite of this, personally I like the brakes. They remind me very much of Alfa Romeo brakes - more effort but more positive. In view of the crackling that has developed, which I understand is more or less standard, at least on these brake drums, shall we fit the 35° servo cams and make tests, or not? If these cams have the effect of increasing the front braking, which I understand they will have, I think it will be an advantage. I shall be interested to have your views on the way you intend getting over the "bell tinkling effect" set up after the brakes have been applied. [Signature: Sr.] P.S. With reference to paragraphs 5 & 6 on Page 2 of my memo. Sr3/ET.I.2.37, concerning chassis B 8 GA, we plugged up 8 holes on the front portion of the cylinder head, and not at the rear, as stated. Please excuse the mistake. [Signature: Sr.] | ||