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).
Hispano-Solex carburettor air silencer design and performance, with recommendations for experiments on the Phantom ll.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan041 | |
| Date | 20th December 1930 | |
| (11) up in an ingious way. They use a small bronze bridge piece bolted at the top and bottom of the alum bridge piece to form a bracing bar. The crankcase is recessed to receive this part. See sketch. I do not know why this practice should be found necessary on the car and not the aero engines. Car Carburetter Air Silencer. The twin choke Hispano Solex is used on both the large and small cars and they have taken the air intake right down into the crankcase. Two breathers containing gauze and baffles are place front and rear of the crankcase and supply the air to the carburetter via the crankchamber. They said the reasons for this are - (1) To act as a silencer. (2) To obtain clean and warm air and absorb fumes. (3) Cool air flow through crankcase. Later I had a run on one of the Boulogne model Hispanos and paid special attention to carburetter silence. There was an entire absence of the usual carburetter roar associated with twin carburetters. This is of particular interest to us now that we are starting experiments with a similar type carburetter for Phantom ll and it would be advisable to consider some such intake scheme for experiment. This method appears a very efficient way of silencing without loss of performance which nearly always results from the usual air silencer. The carburetters were fed by an electric petrol pump. The top gear acceleration on the Boulogne model was excellent and the engine very smooth. The springing however was very harsh. The general impression gained at the Hispano works is that with their present established design of aero engine they have got down very well to its production and produce an excellent finished job. They have the capacity to turn out 100 engines per week if required. Their general workmanship is certainly without criticism and the work appears to flow through shops in a very efficient manner. | ||