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).
Description of an engine's offset cylinder 'desaxe' arrangement and induction pipe depression.
| Identifier | WestWitteringFiles\Q\February1927-March1927\ 108 | |
| Date | 23th April 1925 guessed | |
| contd :- Print No. 6. shews the induction pipe depression which is remarkably low and only .7" of mercury at the speed of maximum power. This is lower than on the F.10. while the Goshawk at speed of maximum output is as high as 2.5" of mercury. This should result in good filling of the cylinders. OFFSET CYLINDERS. A rather unusual feature in the design of this engine is the 'off set' or 'desaxe' arrangement of the cylinders with respect to the crankshaft which amounts to 10 m/m.{Mr Moon / Mr Moore} (see diagram) This results in the top and bottom dead centre positions being assymmetrical with regard to the angular position of the crankshaft, requiring 181° 31' 55" movement for the piston to complete the down stroke and 178° 28' 5" for the upstroke apart from any other effect. The off-setting exerts a slight influence on the valve lift diagram when plotted against a piston displacement base but this is not appreciable. contd :- (bsg.2) Diagram Text: CYLS. ARE OFFSET 10 M/M.{Mr Moon / Mr Moore} ROTATION. OFFSET 10 M/M.{Mr Moon / Mr Moore} TOP CR.{Mr Cra???ster / Mr Chichester} 1° 56' 33" BOTTOM CR.{Mr Cra???ster / Mr Chichester} 3° 28' 28" | ||