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 GB.1250 torsion test performed on a Bentley front axle.
| Identifier | ExFiles\Box 84\3\ scan0282 | |
| Date | 6th March 1936 | |
| X201 FILE. HS{Lord Ernest Hives - Chair}/WB.{Mr Brazier/Mr Bell}1/JH.6.3.36. Bentley Front Axle. GB.1250 Torsion Test. A completely machined axle fitted with a standard pivot and pivot pin at one end was secured by its spring pads, and a gradually improving torque (applied by the double lever method to obviate bending) applied to the pivot, the angular deflections and permanent sets being recorded on a dummy carrier plate. The result shown in the attached graph show that permanent set commenced at 2400 lbs/ft. i.e. after being subjected to an angular deflection of 4.5° - the ultimate torque measuring 4490 lbs/ft. The main failure occurred at the pivot pin bore but there were also two slight fractures in the neck of the axle in the vicinity of the locating screw - see attached sketch. It is interesting to note that when dismantled, the pivot pin was sound, but was found to have bowed .001". HS{Lord Ernest Hives - Chair}/W.Bell. | ||