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).
Test report on Bentley III torque arms.
| Identifier | ExFiles\Box 100\1\ scan0060 | |
| Date | 26th November 1937 | |
| ZOOB LES What thickness material are you proposing to go to Rm{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/W. Bell. c. to Rm{William Robotham - Chief Engineer}/Les.{Ivan A. Leslie} Rm{William Robotham - Chief Engineer}/WB.{Mr Brazier/Mr Bell}2/CB.26.11.37. BENTLEY III TORQUE ARM TEST. - FB.2924. WHb Three torque arms A, C & D made by the Projectile & Engineering Co., were tested on the rig shown sketched on the attached chart, fig. I. Loads were applied until failures occurred, readings being taken at the points A, B, C, G & H as shown in table II on the chart. Arm "A" made of .104" (12 SWG) material and with all joints arc welded, failed under a load of 4,000 lbs., the failure occurring at the top welded joint, shown in fig II.A. Under the maximum estimated load of 1,500 lbs., the arm was not distorted in any way. Arm "B" made of material of similer thickness, but with the joints carbon arc welded, failed under a load of 3,500 lbs., the welding at the top joint having failed over more than half its length - see fig. II.C. Under a 1,500 lbs. load however, the arm was unaffected. As in each case, the welding had failed and no apparent damage done to the material itself, a third arm "D" (FB.2924) of thinner material .080" (14 SWG) was tested. At 1,500 lbs. load, the test piece was just showing signs of failing, a decrease in height of .002" across G.G. being measured with a corresponding increase in width of .0015" across H.H. The load was then gradually increased to 2,900 lbs. before the material buckled just below the top joint - see fig. II.D. The welding on this specimen was undamaged. In all three tests, no bowing over the length of the arm had occurred. Rm{William Robotham - Chief Engineer}/W. Bell. | ||