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).
Results of crank tests for DES.995 models, including test conditions and a resume of previous tests.
| Identifier | ExFiles\Box 63\4\ scan0139 | |
| Date | 4th April 1932 | |
| To Rg.{Mr Rowledge} From Hs{Lord Ernest Hives - Chair}/Bl. X4 99 Hs{Lord Ernest Hives - Chair}/Bl.5/MJ.4.4.32. DES.995 MODEL CRANK TESTS. Three models of DES.989 crankshaft (.295" webs) stamped Vicker's Nitra Steel, were tested under the following conditions:- Rig Speed 285 R.P.M. Stroke 6 ins. Flywheel Inertia 130% (19.55 lb.ft.2). A time limit of 100 hrs. was imposed. CRANK INDEX. | TIME RUN. | TOTAL REVERSALS. | AVERAGE R.P.M. | RESULT. ---|---|---|---|--- V.C.M.1 | 100 hrs. 15 mins. | 3,387,860 | 282 | O.K. V.C.M.2 | 100 hrs. | 3,359,920 | 280 | O.K. V.C.M.3 | 100 hrs. | 3,361,060 | 280 | O.K. Resume of Previous Tests. Model crank tests were originally run at a rig speed of 300 R.P.M., using a U.648 flywheel. Models of E.32053 and DES.989, of S/NCR material, eventually ran successfully for 10,000,000 reversals (over 200 hrs.) but failed when the flywheel inertia was increased by 30% to 19.55 lb.ft.2. Another model (with .295" webs) accomplished 10,000,000 reversals without failure, and it was decided to increase the rig speed to 400 RPM. This caused the failure of the model after 129,080 reversals, and a model of E.32053 also failed under these conditions after 54,560 reversals. Further tests on DES.989 (.295" webs) models, in various materials were made under these conditions (i.e. 400 R.P.M., 130% flywheel inertia), but it was decided before running the "Vicker's Nitra" models, to revert to the slower speed, whilst retaining the increased flywheel inertia, since the failing times, with the increased speed, were too short to enable reasonable comparisons to be made. Originally the rig was driven by a separate motor, but before commencing the "Nitra" cranks it had been arranged to run through a countershaft from a mainshaft. The same rig is also used for other tests which are constantly run at 285 R.P.M. and since this decreased speed is approximately equal to a decrease of only 1% in the flywheel torque it was not altered. Hs{Lord Ernest Hives - Chair}/W.Bell. | ||