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).
Modifications to the Claudel-Hobson carburetter diffuser jet for Condor, Eagle, and Falcon engines.
| Identifier | ExFiles\Box 37\2\ scan 202 | |
| Date | 29th July 1918 | |
| R.R. 22a (400 T) (S.C. 536. 18-2-16) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1546. X3188 To EH. from E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to EFC. 29th July 1918. E2/G29718. X3188 X1853 X3010 RE CLAUDEL-HOBSON CARBURETTER DIFFUSER JET We have received from Mr. Bailey, a leaflet printed by Messts. Hobson's entitled "Modifications, July 1918" concerning their carburetters. There are three points which seem to require some application on our part to the diffuser jets we are using in the "Condor", "Eagle", and "Falcon" engines, (1) It is instructed that the pilot jet be mounted in series with the main jet, which apparently means that the holes feeding the pilot tube jet with petrol should draw their supply from the reservoir within the diffuser tube which is supplied by the main restriction jet, instead of drawing direct from the petrol reservoir in the boss of the carburetter carrying the diffuser jet. Personally, I have never seen a jet made which did not follow the former specification. Our standard variable jet is obviously in series. Further, for the carburetters H.C.7/8 the petrol supply holes in the pilot jet tube should be 90 mm. from the top of the tube, so that they shall receive no petrol when the engine is running at cruising speed, and the level of the petrol in the jet reservoir has fallen nearly to the bottom. This has the effect of preventing any "snivelling" from the pilot jet into the lower pressure within the throttle barrel with the throttle half shut, and thus results in greater economy. Contd. | ||