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).
Flooding tests on a 25/30 HP model to provide an effective overflow drain for a Stromberg carburettor float chamber.
| Identifier | ExFiles\Box 20\9\ Scan138 | |
| Date | 8th April 1936 | |
| Ha/FP.{F. Potts}11/KW.8.4.36. 25/30 HP. Flooding Tests. Tests have been carried out in conjunction with the Stromberg DG.42 Carburettor, to provide an effective overflow drain for the float chamber. Part Under Test. E.60903 Overflow Pipe. Object. The size of pipe required to enable an open vent to be used. Results. A vent .325" inside dia. was fitted to the float chamber lid{A. J. Lidsey} (see sketch). At .187" from the base of the vent, two .187" holes were drilled to take the overflow from the chamber. The first pipe and banjo tested was 3/16" bore, 1/4" piping. This did not prevent the petrol flooding over the vent pipe. A 1/4" bore pipe and an E.59979 5/16" banjo was fitted, this also flooded. The dixtampo connection to the drip tray below the float chamber was then opened out from .125" to .171" dia. This enabled the pipe to take the excess petrol without rising up the vent tube. Conclusion. (a) A vent tube .325" inside dia. required for the float chamber. (b) A 5/16" pipe, 1/4" dia. bore, is required from the float chamber lid{A. J. Lidsey} to the dixtampo, at the drip tray. (c) The bore of the dixtampo must be increased to .171" dia. from .125" dia. This bore must not be increased further, otherwise the petrol will build up in the drip tray and overflow. These tests were carried out, full bore flooding conditions, and an S.U. pump was used. From the dixtampo at the drip tray, downwards, the scheme is standard. Ha/F.Potts. | ||