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).
Comparative power curves between old and new carburettors.
| Identifier | ExFiles\Box 36\2\ scan 112 | |
| Date | 27th April 1927 | |
| R.R. 493 (40 H) (SL 45 12-7-25). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. 27.4.27 COPIES TO: R.C.J. BJ. WOR.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} EP.{G. Eric Platford - Chief Quality Engineer} PN.{Mr Northey} OY. Expl. No. 3996 REF. Hs{Lord Ernest Hives - Chair}/VH1/LG29.4.27. OBJECT OF TEST. Comparative power curves with old Lec.2322-6-52 and new carbs. in the vee - Lec.2382-5-6. TESTER. V.Halliwell. CONDITIONS. X-F-12. Pistons - Originally E.23480 with skirts of decreased length and unstrengthened piston rings. Valves - Unstrengthened tulip type E.27944. SUMMARY OF TEST. The power curves attached shew the results obtained with the new carbs. as compared with the results from the original carbs. in the vee - the two curves being run off consecutively on the same engine. In each case there were no intakes fitted - only the bare carburetters. The corresponding depressions were also taken in the induction manifolds. It was thought that the loss in power with the new carbs. was a restriction effect due to the bulge caused by the portion of the float chamber which projects into the air intake. The dia. of the diffuser just below the choke is 0.1" more than on the old carbs. - this further restricting the flow of air at this point. Another feature of the intake at this point is a pocket which exists behind the diffuser opposite the intake flange. For a trial run to reduce the restriction a set of diffusers were converted into jet nozzles having a stem dia. of 0.44" - the diffuser tube dia. in the new carb. being 0.9". Adjustable jets were used to correct the mixture when the engine had been run up to speed. contd :- | ||