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).
Modifications to the Wraith III rear wings, axle, and body.
| Identifier | ExFiles\Box 159\2\ scan0039 | |
| Date | 3rd September 1937 | |
| 1369 DA.{Bernard Day - Chassis Design}1/G.3.9.37. Wyman noted WRAITH 111 - REAR WINGS. ------------------------- The reasons for the wide gap which appears on Wraith cars between the rear wing and the tyre are the use of the standard P.111 axle with .850 hypoid instead of the Wraith axle with 1.625 hypoid and the use of 6.5 section tyres instead of 7.000. The Wraith bodies were designed for 1.625 hypoid and 7.000 tyres, and in order to use .850 hypoid it was necessary to raise the car .800, by substituting rear springs flat under normal load for those with .800 negative camber, originally proposed. This was necessary in order to maintain the clearance of the propeller shaft with the frame cross members and the rear floor of the body. Another reason for the excessive gap is that the bodies are mounted too high on the frame, in the worst case .600". The body drawings require modifying to suit these changes, which were made after the bodies were ordered, and the next body can be correctly built. The reason for the tyre hitting the side of the wing in spite of the large gap is that the rear buffers have not been modified to suit the raised car, and as a result the bump obtained is too great. A packing is required under the present buffer. It will be remembered that the use of the P.111 axle with resulting modifications was originally confined to the first car, and the modifications were naturally not extended to all cars. This now requires doing. DA.{Bernard Day - Chassis Design} | ||