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).
The performance of original and new clutch springs.
| Identifier | ExFiles\Box 90\1\ Scan196 | |
| Date | 29th October 1937 | |
| Rm{William Robotham - Chief Engineer} .263 B-23-AE RLB Original clutch springs 38 lbs mean now (29/10/37) 50.5 mean. with old springs moderate slipping, now good, can only be made to slip by brutality, and in my opinion is suitable for customer's use. The servo spring now works well VPE 29/10 | ||