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).
Analysis of power loss caused by air silencer components and proposed modifications to reduce it.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan009 | |
| Date | 1st May 1930 | |
| -2- Hs{Lord Ernest Hives - Chair}/BP.1/H.J.5.30.Contd. (8%) at 2750 R.P.M. This figure may be split up as follows :- air port cowling = 4 BHP.(3%); air-silencer end pieces,E.804 85/6 = .8 BHP.(.6%); inner silencer tube E.80481 = 2.2 BHP.(1.7%); outer silencer tube E.80482 = 3.5 BHP.(2.6%). Referring again to V.851, it will be noticed that the worst offender is the outer silencer tube (E.80482), the effect of which is felt below 1750 R.P.M.; the loss caused by the air-port cowling being almost as great. It is proposed to reduce the former loss by increasing the size of the apertures in the outer silencer tube; but to reduce the latter it would apparently be necessary to further increase the annular space around the air-valve ports, which would require an altered casting. A slight improvement could probably be effected to the existing carburetter by turning a groove around the outside of the air-valve body in the vicinity of the ports. These modifications are to be carried out as soon as possible, when it is hoped that the power loss will be materially reduced. Regarding the silence of this carburetter it does not appear to be any noisier than the original one of this type. The loud hiss (caused by the opening of the air valve on the Std. carb) is entirely absent, but the roar appears to be very slightly louder than on the standard instrument. Hs{Lord Ernest Hives - Chair}/CMP. | ||