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).
Tests conducted on an Air Silencer Carburetter S.S., detailing power loss and modifications.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan217 | |
| Date | 20th December 1929 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. C. to SG.{Arthur F. Sidgreaves - MD} WOT. C. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} C. HY.{Tom Haldenby - Plant Engineer} ORIGINAL x7080 x7770 AIR SILENCER CARBURETTER S.S. A number of tests have been carried out on the above carburetter (LEC.2734), and the conclusions drawn therefrom are that the air passages are generally small, and that the metering is considerably impaired by the use of a smaller diaphragm and air valve. Comparing the complete carburetter with a standard instrument, a power loss of 10.0% is noted at 2500 R.P.M. (See V.757). This loss may be split up into (a) 6.2% due to the smaller diaphragm and air valve, ascertained by removing the air-silencer and fitting a standard air-intake instead; and (b) 3.8% (the difference) due to the air silencer.(See V.758). It should be noted that this latter figure is the excess of loss over that which is caused by the standard air intake. The standard type air intake is responsible for 2.2% loss at 2500 R.P.M., therefore the air silencer is responsible for a total loss of 6.0%. The spray chamber was now machined out to receive a standard suction chamber; but as the space between the air valve ports and the spray chamber body had consequently become rather small, a groove was turned round the suction chamber at the air ports, thus increasing the annular clearance. A standard high speed choke and diaphragm were also fitted. The carburetter was again fitted with a standard air-intake; thus converting it into a standard instrument, with the exception | ||