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).
New dynamometer power charts and a carburation fault observed at 1000 RPM during engine testing.
| Identifier | ExFiles\Box 72\2\ scan0090 | |
| Date | 14th November 1928 | |
| OY1.R.11.14.28 Y8991 November 14th, 1928. TO: Mr. Caswell cc - Mr. Nadin Mr. Beaver Mr. Burton Mr. Poole Mr. Ainsworth Mr. Hives(England) FROM: Mr. Olley E N G I N E (Dynamometer Test) New charts. I attach 2 prints A-12879/80 of Dynamometer Power charts for the 14/52 and 13/51 axles respectively. The one for the 13/51 axle is new and will be required whenever 13/51 axles are used on dynamometer test. I think you will find it an advantage to have prints made of both these for the dynamometer house. Instead of the obsolete "minimum power curve" of the present chart I have given a curve representing the average of 6 cars of 2301 series. "Flat Spot" at 1000 Revs. This curve illustrates a fault in carburation that we first noticed on the Stromberg test, (and which shows even on the original English curves of the "green book") namely the falling off in engine torque at 1000 R.P.M. (26 m.p.h.) The dynamometer pull falls short 5 lbs. of its correct position at this speed. This 5 lbs. is 25 lbs. at the tires. That is nearly 5% of the total tire thrust. Obviously this fault has something to do with faulty low speed acceleration. Anything which we can find which will reduce this fault will have a great effect on the acceleration from 10-50 m.p.h. Manifold. The fact that it occurs with the Stromberg and with every type of air valve tested, and appears on all our dynamometer tests, shows that it has nothing to do with the carburetter. On A-12879 I have drawn the Stromberg curve in pencil to illustrate this. It possibly has to do with distribution or with a resonance effect in the intake manifold or exhaust system. -continued- | ||