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).
Phantom III gearbox testing, detailing failures and running times of various components.
| Identifier | ExFiles\Box 94\2\ scan0150 | |
| Date | 8th January 1937 | |
| 328. E.{Mr Elliott - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. to Hs.{Lord Ernest Hives - Chair} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} c. to By.{R.W. Bailey - Chief Engineer} P.III GEARBOX TESTING. Since the reinstallation of our water-brake chassis dynamometer, we have been able to do some intensive gearbox testing. All running is done full throttle at 1500 r.p.m. Box No.4.HS{Lord Ernest Hives - Chair} with Cadillac 45° spiral angle gears. In 3rd gear. (1) 3rd Speed gears 20 1/4 hours - no failure (2) "Concertina" coupling 16 1/4 hrs. " " In 2nd gear. (1) Tab washer locking nut on rear of 2nd motion shaft, sheared several times after running times varying between 55 minutes and 6 hours. The tighter the washer is done up, the longer the washer lasts. (2) Thread at rear of 2nd motion shaft fractured after 5 hours and 6 1/2 hours. (3) Bearing at rear of 3rd motion shaft failed after 5 1/2 hours. (4) Now standardised 2nd speed coupling N.Sch.4824, 10 hours without failure. (5) The same 2nd speed pieces were then given .030 diametrical clearance, and after a further 13 1/2 hours the middle ring was cracked at root of the radius. (6) 2nd speed gears 11 1/2 hours without failure. Another pair ran 12 hours without failure. (7) Flange of 2nd speed pinion bush broke after 10 hours and 13 1/2 hours. The constant mesh pair of gears have completed 44 hours. The 13 ball no gap bearing on the 1st motion shaft has done 23 hours. | ||