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).
Design choices for the Japan 3 engine, including ignition, governors, and connecting rod lengths.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan260 | |
| Date | 29th January 1931 | |
| E.{Mr Elliott - Chief Engineer} HS.{Lord Ernest Hives - Chair} FROM K.{Mr Kilner} (At Le CanadelHenry Royce's French residence.) c. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} c. to HY.{Tom Haldenby - Plant Engineer} RHC.{R. H. Coverley - Production Engineer} JAPAN 3. ENGINE. LeC. 2853. x5770. x8030. x6105. This seems quite right. The only additional suggestions I can make at the moment are that the crank pins shall be bored rather larger for lightness, and arrangements on crank for 4 balance weights equal to about half total out of balance. If we arrange to go straight on with double ignition (HS.{Lord Ernest Hives - Chair} and Mr. Minchin say it would be appreciated) I should like to see double head for this and P. 2. It would be better with a single governor because of synchronism and our double governor is so very efficient that it might control two, but there are arguments for 2 governors, and if we could get them very simple to make the general design might be easier. I imagine central spur driving 2 heads in the same direction, thus - or thus - [Diagram showing two options for driving two heads] [RECEIVED stamp: 3 FEB 1931] E.{Mr Elliott - Chief Engineer} will try what suits the drawings best. e.{Mr Elliott - Chief Engineer} CON. ROD LENGTHS. After much discussion there seems no very definite wish for long rods, but I understand that probably the longer rods are still worth their cost, because although they only help the small percentage we originally estimated several years ago they do reduce several troubles - i.e. say 1/20 less maximum bearing pressure, 1/10 less flywheel needed, or 1/20 less balance weights, and 1/10 less speed variation and over-running forces. Possibly they are needed to get the camshaft wheel below the top face of crankchamber. In short I agree to whatever suits the general design best, but somewhere between 1.8 and 2. Piston, skirt clearance, and possibly oil consumption all favour long rods. R.{Sir Henry Royce} | ||