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).
List of tests carried out to overcome drive to overrun transmission chunking.
| Identifier | ExFiles\Box 124\3\ scan0363 | |
| Date | 18th October 1935 | |
| F.T.H { L.E. Smith } <1049? Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}25/KW.18.10.35. Drive to Overrun Transmission Chunking. Attached is a list, not in chronological order, of tests so far carried out to overcome this trouble. The noise is characterised by the fact that it is worse the lower the speed, and that there is always a maximum speed above which chunking is not audible. CAR | TEST | RESULT (1) 29-EX | Original separate synchro 2nd speed J-3 box | Worse than standard Ph.II (2) 29-EX | 25º gears having very little total backlash. 3rd gear .013 at 1.875 on 3rd motion shaft. | Very good (3) 33-EX | C.M. and 3rd continuous 2nd motion shaft gears tight on splines | Improvement (4) 35-EX | C.M. .0045 pitch line} 3rd .0045 "} Sliding piece .002 on splines .003 in top dogs, .005 in 3rd | Bad in 3rd gear (5) 35-EX | Same as (4) but C.M. pitchline slack .001 | Much better in 3rd gear. (6) Any SpectreCodename for Phantom III | Heavy flywheel or softer rubber mounting. | Improvement (7) 30-EX | Mobiloil 'C' instead of Hi-Press light | No improvement | ||