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).
Design alterations for an induction system using a Stromberg twin downdraught carburetter.
| Identifier | ExFiles\Box 124\1\ scan0250 | |
| Date | 23th August 1939 | |
| BK{A. Birkett - Commercial Manager}/NS{Norman Scott} c. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/oms. c. Rm{William Robotham - Chief Engineer}/ens. 10HH DA.{Bernard Day - Chassis Design}7/G.23.8.39. B.80 - INDUCTION SYSTEM FOR STROMBERG TWIN DOWNDRAUGHT CARBURETTER WITH 1.437" DIAMETER THROTTLES. Please receive herewith :- E.CD.1462 Induction System with Stromberg AA.{D. Abbot-Anderson}25. Carburetter. B.80. This design has been made to the request in Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}14/JR{Mr James Royce} 28.6.39. and includes the following alterations compared with the previous design E.CD.1298.- (1). The main shape of pipes is square instead of circular to match with shape of ports in cylinder head, the area of pipes being equivalent to a 1.750" bore pipe. (2). The height of risers are now fixed, and facing for carburetter is suitable for the 1.437" diameter throttle bores of the Stromberg twin downdraught carburetter AA.{D. Abbot-Anderson}25. (3). The volume of the centre chamber at junction of risers and main pipes has been reduced to a minimum. (4). The water jacket is extended to include the risers and is also considerably lengthened on the longer pipe which feeds the front and rear cylinders. (5). The sloping floor of the centre chamber has been made to effectively drain chamber up to an inclination fore or aft of one in four. The size of the balancing slot between throttles is now specified .750" wide by .250" deep.. A new water return pipe from hot spot is called for, also the petrol supply and drain pipes are altered in length slightly from E.CD.1432 due to the new position of the carburetter. Regarding the size of the drain pipe from the centre chamber of induction manifold, we have retained this at .250" diameter until flooding tests have been made when the final diameter will be determined, the boss for the drain pipe union is shown sufficiently large to take a .3125" pipe union if required. We have discussed the question of core supports for the water jacket cores with Mr. Walker of the Pattern Shop, | ||