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 results for the Wraith gearbox, detailing failures and endurance of shafts and bearings.
| Identifier | ExFiles\Box 8\11\ 11-page147 | |
| Date | 12th December 1938 | |
| 628 To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Da{Bernard Day - Chassis Design}/Hdy.{William Hardy} Rm{William Robotham - Chief Engineer}/PJH.1/JH.12.12.38. WRAITH GEARBOX. We give below the results to date of dynamometer testing on the Wraith gearbox following the failure of a 1st. motion shaft on 29.G.VI. All running has so far been in 3rd. speed at 1,500 r.p.m. 1st. motion shafts. (1) Original type GW.1829 S/ZNX failed, 10½ hrs. (2) " " " cracked 20¼ hrs. (3) " " " softened locally in region of oil retaining 12 hrs. thread - cracked. (4) Strengthened type PD.310 S/ZNX 45º helix. Still satisfactory. 64 hrs. 1st. Motion Shaft Bearings. (1) Original type CW.788 45º helix balls chipped. 13 hrs. (2) Original type CW.788 45º helix Ball chipped. 18 hrs. + 35,000 miles. (3) R.{Sir Henry Royce} & M.{Mr Moon / Mr Moore} 40 MJC. 45º helix failed. 12 hrs. (4) R.{Sir Henry Royce} & M.{Mr Moon / Mr Moore} Duplex type D.M.J.T.40. 45º helix. Balls chipped. 44 hrs. 3rd. Motion shaft. Shoulder broken off 62 hrs. | ||