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).
Choke flow testing procedures and the justification for using a dedicated flow rig.
| Identifier | ExFiles\Box 122\4\ scan0174 | |
| Date | 30th June 1938 | |
| -4- Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}8/JH.30.6.38. CHOKE FLOWS. Choke flows may be carried out to represent cold start characteristics. With choke closed and throttle set at normal starting position the vacuum valve is slowly opened from the closed position. Air and fuel flows at integral carburetter depressions are noted up to an arbitrary depression of 15" hg. Hence air flow and mixture ratio are plotted against carburetter depression. ................. The rig may further be used for the flowing of manifolds, valve ports at various valve openings, air silencer restrictions etc., as well as in the development of vacuum controlled chokes, spark controls etc. A criticism which must obviously be levelled at the purchase of a flow rig, that the carburetter company themselves own a flow rig and should be able to satisfy our requirements, is met by the fact that the carburetter company's programme must of necessity be too large to include a tryout of all our proposals and modifications. To quote a case in point, the tilting of the P.III carburetters alone necessitates the resetting of the entire carburetter, added to which is the fact that the level of fuel is far lower than originally intended by the makers. With a flow rig the task of restoring the characteristics to the original would be a comparatively simple one. (c) COSTS. An approximate cost for the outstanding items which would have to be bought outside is appended. The remainder of this apparatus could be costed by the Planning Department and built by the firm if desired. | ||