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).
Suggestions to overcome the distortion of the floatchamber lid on a Wraith III carburetter when tightening the petrol drain pipe union.
| Identifier | ExFiles\Box 7\4\ X 608 Carburetter-page36 | |
| Date | 7th July 1938 | |
| 608 DR/JMS. c. Rm.{William Robotham - Chief Engineer} S.P.R. A.F.S. WRAITH 111 - CARBURETTER. DISTORTION OF FLOATCHAMBER LID{A. J. Lidsey} CAUSED WHEN TIGHTENING PETROL DRAIN PIPE UNION. A number of suggestions have been made to overcome the trouble of distortion of the floatchamber lid{A. J. Lidsey} when tightening up the union nut of the floatchamber overflow pipe, which is attached rather rigidly to the drain pipe from the catch tray beneath the accelerator pump operating mechanism. One suggestion was to do away altogether with the catch tray, as there is only a small amount of petrol leakage at this point, which occurs when the carburetter is flooded. If this were done there is just a risk of causing fire by petrol dripping near to the sparking plug terminals. Assuming the tray therefore is necessary, the following methods of avoiding petrol getting near the sparking plugs may be considered, each of which avoids the distortion trouble.- (1). Carburetter as at present with die cast tray and with the pipe connection from tray omitted and the hole plugged up, allowing the petrol to evaporate from tray. (2). As (1) except that a separate short drain pipe is fitted from the tray leading petrol to a point outwards from engine to just below sparking plug level. (3). As (1) with complete set of drain pipes not rigidly coupled to each other as shown on E.CD.769. (4). If it is desired to use a standard type of Stromberg carburetter without the die cast tray to reduce the cost of the carburetter, a loose tray could be fitted for petrol evaporation as shown on E.CD.783. We send herewith the two aforementioned design drawings:- E.CD.769 Modified Floatchamber Overflow Pipe - Wraith lll. Carb. E.CD.783 Petrol Catch Tray for Stromberg Carburetter - Wraith lll. These designs should not be detailed for the time being, unless asked for by the Experimental Dept. as they are at present trying various types of Stromberg carburetters and the question of the petrol drains, leaking floatchamber lids etc. will receive attention during the normal experiments before making a final recommendation. | ||