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).
Failures of dynamo brushes, commutator, and steering box during a 10,000-mile test.
| Identifier | WestWitteringFiles\I\May1922\ Scan11 | |
| Date | 5th May 1922 | |
| R.R. 236A (10M I/S Dd 703. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 29/17. ORIGINAL re 4CII R1/M4. 5. 22. To Hs.{Lord Ernest Hives - Chair} EF. & Hy.{Tom Haldenby - Plant Engineer} from R.{Sir Henry Royce} and 10,000 miles c. to OJ. BJ. Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} PN.{Mr Northey} EFC. (Stamp) RECD MAY 10 1922 HS{Lord Ernest Hives - Chair} X4219 RE GOSHAWK 12. Scau 48. I regret to hear that we had rather bad experiences near the end of the 10,000 miles but I expected more and Works should be congratulated on no breaks through bad material. (1) DYNAMO BRUSHES. X.4333 The failure of these have vexed me very much as I gave exact instructions which were not followed, and someone must be made responsible. A certain brand of all carbon brush of Le Carbon make was instructed in several memos: instead I understand a copper-carbon Morganite high conductivity brush was used - result, disaster, loss of money, and disgrace. (2) DYNAMO COMMUTATOR. X.4333 This may have been due to overheating through bad brushes, but our dynamo runs very fast, and should be tested at all temperatures up to 5500 r.p.m.: in a quick note to Derby I have suggested short pieces of steel tube (rings) embedded in the end bakelite, also a central tube or the shaft arranged to pull the commutator together end-ways and prevent the end rings spreading; this latter idea seems quite necessary. I always thought this American scheme was not perfect enough but feared to make the work more elaborate. The other small faults suggest more perfect inspection and testing both as units (factory) and after being erected: this we expect will come. (3) STEERING BOX. This breakage reminds one of the similar trouble with the 40/50 but it may not be the same cause: it naturally must be due to stresses arriving by the lower lever or upper tube or some internal stress, or a combination of these. I believe it comes principally from the writhing of the frame down the upper tube due to the stiffness sideways of the dashboard: if it is a single cause it can be separated and proved on the bumping rig, or the supporting tube can be cut so as to shew if any movement would relieve i.e. make a tube with joints in the form of a flange, the bolts of which can be removed. I have suggested other treatment elsewhere, but I feel sure we ought to find the cause first. It has occurred to me that the stress due to steering might be less with irreversible steering, but also they might be greater by simpler reasoning - this should be tested. The spring buffers in the rear end of the long steering tube should have much greater clearance. There was only about .05 in that on No.4 Gos.ll. (1) | ||