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).
Proposed design modifications for the 40/50 HP Distribution Board and Tyre Pump.
| Identifier | WestWitteringFiles\F\April1921\ Scan19 | |
| Date | 12th March 1921 | |
| To HS.{Lord Ernest Hives - Chair} ) from E.{Mr Elliott - Chief Engineer} " DA.{Bernard Day - Chassis Design} ) Copy to CJ. " " BJ. " " WOR.{Arthur Wormald - General Works Manager} " " BY.{R.W. Bailey - Chief Engineer} " " WD.{Mr Wood/Mr Whitehead} " " EFC. RE VISIT OF MESSRS. HIVES AND DAY TO WEST WITTERINGHenry Royce's home town. ON 6 EX - 12th MARCH, 1921. (1) 40/50 H.P. DISTRIBUTION BOARD. X4173 x2515 A place must be provided for carrying fuse wire within the distribution box. Fuse holders seem to be rather loose in their grip on the fuse carriers. Special attention must be given to the material from which the spring fingers of the fuse holders are made, so that it shall be as elastic as possible. (2) 40/50 H.P. TYRE PUMP. The Works found it difficult to get the crankshaft true owing to slight inaccuracies which occur in the grinding operations. Mr. Royce thinks that there is no need to change the design, and that the Works will do better with some special tackle for jigging the pieces, also the standard of inspection of the finished crankshaft must not be too high. The inlet valve plug has been made with very coarse thread. This thread should be made much finer (20 T.P.I.) and the plug head should be formed with a recessed square top. The piston rings are too stiff, they should be .075" deep instead of nearly .100". Also, Mr. Royce would like two wider rings instead of three narrow ones, to make the job a little more simple. Referring again to the crankshaft of the pump, Mr. Royce suggests that this should be tried with central bolt and washers to tie the shaft together to avoid a possible error due to the threads of the crankpin, which might throw the shaft out of alignment in the assembly. Mr. Royce thinks that the big pump gear wheel might be in bronze. The spigot on the pump cylinder was too tight a fit in the crankcase, and the bolt holes also were too close a fit. These two jobs can be made quite slack, as the only essential condition is that the cylinder axis shall be at right angles to the crankshaft axis. Mr. Royce thinks that the rounding of the teeth on the gear wheels might be dispensed with on the score of economy if found unnecessary in practice. Perhaps the rounding of the teeth on one wheel only would be sufficient. The oiling scoop on the big end was not used, but the more expensive scheme of oiling was adopted. Mr. Royce thinks that a simple scheme of external oiling for the big end should be adopted, with no internal oil passage and no scoop, but with oil collecting holes in the top of the big end, and also oil holes in the bottom for oil to splash in. The crankshaft webs should be drop forged with panels in them on the crankpin side, as in sketch. These will be lighter and will balance the piston partly. (Contd.) | ||