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).
Details on a new, lighter back axle design, its adjustments, and strength compared to the 1906 pattern.
| Identifier | ExFiles\Box 2\6\ B002_X 140 141 157-page025 | |
| Date | 18th June 1912 | |
| 3. New design of back axle having rather smaller dimensions, the chief aim being reduction of weight, and owing to the Works' appreciation of the value of the facility for adjustments in the present standard over X/34 1906 pattern, we have gone a considerable step further to increase this facility which I am sure will result in still better adjustments of these bevel gears. After this box has been thoroughly tested I am in hopes that if it is found satisfactory, and we are convinced of the great-er suitability of the bevel over the worm for our car, we shall be able to have a central portion of this axle drop forged. In passing, it may be of interest to note that Mr Bailey has calculated that this axle will carry in the centre 7 tons before reaching its elastic limits, i.e. before suffering permanent distortion. What it has to bear when dancing over rough roads at high speeds, no one knows, but it can be compared for strength with our old 1906 axle, and i hope it will be found to be considerably stronger without being perceptibly heavier. While making this alteration many small improvements, principally in the saving of weight, have been introduced. Everything has been made as close as possible so that for a gear ratio lower than 3 to 1 the box will be unsuitable, that is to say, we have not worked it out for cars intended to exceed 70 miles and hour except with very high engine speeds. Handwritten note: Extract from FHR 18.6.12. | ||