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).
The design, analysis, and building methods for the Goshawk II front and rear road springs.
| Identifier | ExFiles\Box 49\3\ Scan039 | |
| Date | 10th March 1921 | |
| X.4261 H8 1 To - from DA. {Bernard Day - Chassis Design} c.c. to BN. {W.O. Bentley / Mr Barrington} c. to E.O. X.4261 Road Springs - Goshawk II. DA {Bernard Day - Chassis Design} 4/CB10-3-21 RECEIVED We have made two schemes - "N" Scheme 788 Rear Spring and 790 - Front Springs both of the heaviest weight, namely, 110 and 660 lbs respectively, based on a car of 35 cwt. The method by which these springs have been designed has been shewn on "N" Scheme 771 and "N" Scheme 789, and again both have been analysed by the method shewn on "N" Scheme 779. We wish to point out that though the building up of the spring is not so very difficult a job, there is a considerable amount of trial and error involved. While in the case of the analysis of the spring, there is a very great deal of arithmetical work called for. Particularly so if an exact account is taken of the ends of the leaves by the method shewn on "N" Scheme 787. Because of this latter we have found that it is a great convenience to assume that the ends are square, and that this approximation is very nearly true in the case of leaves shaped as we propose they should be shaped, namely, to the nearest approximation to the hyperbolic shape which gives circular bending, that can be obtained by a simple rolling process. We should like to remark that we know that the methods of building up the spring are not strictly accurate, but we think that the method of analysis is accurate and corrects the errors in building up, except in the case of the top and bottom plate, where, on account of the peculiar conditions of bending, the stress given in both cases by the analytical method is more than it should be. Contd. | ||