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).
Design and analysis methods for Goshawk II road springs.
| Identifier | ExFiles\Box 49\3\ Scan037 | |
| Date | 8th March 1921 | |
| H.{Arthur M. Hanbury - Head Complaints} R.{Sir Henry Royce} D.{John DeLooze - Company Secretary} 295A (Copy from D.A.) c. to E.U. X.4261 DA{Bernard Day - Chassis Design}4/CBB-8-3-21. [Stamp: RECEIVED MAR 9 1921] X.4261 X.4263 (crossed out) ROAD SPRINGS - GOSHAWK II. We have made two schemes "R" Scheme 788 rear spring, and 790 - front spring, both of the heaviest weight, namely, 1100 and 660 lbs respectively, based on a car of 35 cwt. The method by which these springs have been designed has been shewn on "P" Scheme 771 and "N" Scheme 789, and again both have been analyzed 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 of error involved. While in the case of the arithmetical analysis of the spring, there is a very great deal of 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 letter we have found that it is a great convenience to assum 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 parabolic shape which gives constant stress. That can be obtained by a simple grinding 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 buolding up, except in the case of the top and bottom spring 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. | ||