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).
Dynamometer test report on a Wraith gearbox, detailing component failures at different running times and speeds.
| Identifier | ExFiles\Box 8\11\ 11-page154 | |
| Date | 26th January 1939 | |
| 628 To By.{R.W. Bailey - Chief Engineer} From Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. DA.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} c. RHC.{R. H. Coverley - Production Engineer} c. HS.{Lord Ernest Hives - Chair} WRAITH GEARBOX. We have now completed our dynamometer running on this gearbox. The total running time is 149 1/2 hours. During this time there have been 10 involuntary stops. The B.50 box ran a longer test without a stop. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}1/JH. gave an account of the troubles experienced up to Dec. 12th. 10 1/2 hours were run on 2nd. gear and the rest on 3rd., all running full throttle at 1,500 r.p.m. on a 4 1/4 Bentley engine. As regards the running on 2nd. speed After a run of 3 hrs. the nut at the rear of the side shaft was undone. " " " 7 hrs. The 2nd. speed bush flanges failed. " " " 10 hrs. teeth were cracked in the driven gear. As regards 3rd. speed After 54 hours teeth failed in the driven gear. A similar failure occurred on new gears after 69 hours. The strengthened S/ZNX 1st. motion shaft with 45° helix ran 70 hours without failure. The standard Hoffmann 1st. motion shaft ball bearing running with a 35° helix shaft failed after 35 1/2 hours. An R & M Duplex bearing with split inner race running with a 45° helix shaft failed after 44 hours. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||