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).
Unsatisfactory performance and high cost of Ley's 'Lepaz' brake drum material.
| Identifier | ExFiles\Box 120\1\ scan0170 | |
| Date | 12th February 1937 | |
| 1028 To Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} Sg.{Arthur F. Sidgreaves - MD} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Rm{William Robotham - Chief Engineer}/OSH. LEY'S "LEPAZ" BRAKE DRUM MATERIAL. This material seems most unsatisfactory for brake drums. It is very expensive and seems to be prone to squeak. 3.B.IV. was fitted with "Lepaz" rear drums and standard front drums. The rear drums developed an objectionable squeak. On changing the rear drums to standard, the squeak stopped. The "Lepaz" drums were put on another car with a different Ferodo; the brakes immediately started to squeak. Ley's have not quoted for Phantom III. drums yet; verbally they inform us their price is 45/- to 50/- per cwt. as against 44/- for Millenite and 35/- for Chromidium. There are serious disabilities attached to "Lepaz". Leys are quite unable to make standard Phantom III. rear drums. We have given them two alternative designs, each easier to make, and they cannot produce either. In view of the cramped spaces we now have to fit brake drums into, further limitations are a serious disadvantage. Leys can make our front Phantom III. drums. So as to give them every chance, we will order and test a pair. They have the advantage of extra rigidity, Young's modulus being high. When 6.B.IV. is on the road again in France, the rear drums will have "Lepaz" liners. It will be interesting to see if they squeak. "Lepaz" is an unsuitable material for liners for aluminium drums as it imposes more than double the stress in the aluminium than iron does. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||