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).
Modifications to the fabric engine coupling and the epicyclic starter gear on the gearbox.
| Identifier | Morton\M3.2\ img004 | |
| Date | 1st January 1925 | |
| TO [redacted] FROM AJS. Copy to [redacted] Copy to [redacted] Copy to - HS.{Lord Ernest Hives - Chair} ORIGINAL SECRET E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. 'V' SERIES. FABRIC ENGINE COUPLING & MODIFIED EPICYCLIC STARTER GEAR ON GEARBOX, ETC. Handwritten notes: X8310 / X8640 (crossed out) X8650 / X8705 We send herewith Lec. 1973. (original to BY.{R.W. Bailey - Chief Engineer}, print to R.{Sir Henry Royce}) shewing:- (1) Fabric coupling of as large a dia. as can be accommodated by the 40/50 gearbox with such modifications to box as recessed bolt head in front arm. (2) An epicyclic starter reduction gear of reduced dia. (therefore of reduced reduction) which is incidental to the fabric coupling. ? (3) Smaller chain wheel of 20 in place of 26 teeth on starter motor axis; this is incidental to the reduced reduction of No. 2. Referring to (1) this has been entirely redesigned from that shewn on previous drawings, and is flatter and lighter. To accommodate the former feature a slightly shorter first motion shaft is used. Regarding the removal of lock plate retaining wire BY.{R.W. Bailey - Chief Engineer} points out that these can always be readily removed if ends are treated as shewn. We have therefore adopted this scheme in place of the more expensive plier operated hook ends. In dismantling for removing clutch, or for other purpose, three bolts are withdrawn forward, and the remaining three pushed back in recesses in gearbox bearing cover which receives them. This allows first, the easy removal of the spider, and secondly the removal of the disc which, owing to its size and the limitations of space surrounding it, is not quite so easy. To facilitate its removal cone headed bolts are provided in the driven spider. These have an additional virtue in eliminating one of the centring slacks on driven side, the centring on driving side being accomplished by the sheet steel shrouding. Referring to (2), in this we have retained the same number and pitch of teeth in sun as used at present. This has fixed the number of teeth in the planetaries as a number which added to 1 was divisible by 3. 17 has been selected as the most expedient. The reduced reduction of the epicyclic means a 30% larger torque is imposed on sun wheel shaft than hitherto. This has been compensated for partly by:- (1) | ||