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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).
Comparison of power output from Claudel and S.U. type single jet carburettors on a P10G0 engine.

Identifier  ExFiles\Box 121\3\  scan0040
Date  28th October 1931
  
81452

To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Ra.
c. to Ss.{S. Smith} Wor.{Arthur Wormald - General Works Manager}
c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer}
c. to Hy.{Tom Haldenby - Plant Engineer}

Hs{Lord Ernest Hives - Chair}/Ra.3/KT. 28.10.31.

X1487
Y1452

POWER OUTPUT. SINGLE JET CARBURETTORS
CARS. COMPARED WITH P10G0 ENGINE
HIPPER TYPE.

We obtained a power of 34 B.H.P. with a Claudel carb., free area past choke 1.46 sq.in. on a Japan unit with a 112' shaft, high lift valves and a c/r of 5.13
When we tried to reproduce this with an S.U. we were 10 HP. down, as shewn on Curve (1). Due distribution with the S.U. appeared to be quite good at the top speeds with pipe "B", but in view of the large discrepancy in power output between the two carbs. we decided to try another pipe on the S.U. "A". This pipe gave an increase of 8 B.H.P. and almost equalled the Claudel though it was poor for distribution at low speeds.

The inference we draw from these results is that we can get as good power from a single jet as a diffuser, though the former is more susceptible to distribution troubles. Incidentally we took the induction pipe depn. opposite No.4 & No.5 cyls. in these tests and you will note that the results shew quite a wide variation in depression between the two points.

Hs.{Lord Ernest Hives - Chair}/Ra.
  
  


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