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).
'SS' engine development work, comparing its performance and specifications against the F.2.B. series engine.
Identifier | WestWitteringFiles\S\September1928-October1928\ Scan187 | |
Date | 26th October 1928 | |
To R: from Hs{Lord Ernest Hives - Chair}/ACL c.c. to BJ. Wor.{Arthur Wormald - General Works Manager} c.c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c.c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL. Hs{Lord Ernest Hives - Chair}/ACL1/LG26:10:28 'SS{S. Smith}' ENGINE DEVELOPMENT WORK. X7770 (crossed out) X7771 We have carried out various tests on the 'SS{S. Smith}' engine and made comparisons with the std: F.2.B. series engine and the information derived from these tests has shewn that we have in the SS.{S. Smith} an engine - in its present form using the std. Phantom chassis carburetter - giving 10% increase in power over the F.2.B. series engine. We are concentrating on obtaining still greater power output and consider this engine is capable of further improvement in this respect, particularly so at the higher speeds. Analysing the results so far obtained we may say in a general way that the increased power output over the F.2.B. series engines is due to :- (1) Larger valves and ports. (2) Increased duration camshaft helping the larger valves. (3) Slightly higher comp: ratio - 4.5 to 1 compared with 4.25 to 1. A further probable gain may exist in slightly better mechanical efficiency due to the lighter pistons and the fewer rings. A mechanical efficiency curve is appended obtained by the usual method of 'cutting out' cyls. but we have no direct comparison to offer for the F.2.B. engines. A further power gain with the SS.{S. Smith} engine will be made possible by the introduction of the new RR. low depression expanding carb. from which instrument we hope to have the power output performance associated with the low depression static contd:- | ||