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Performance analysis memo detailing brake horsepower figures and discussing Brooklands lap times.


Identifier  ExFiles\Box 5a\5\  05-page196
Date  24th December 1931
  
HW/Wal/MA.24.12.31. Cont'd

At 70 M.P.H.
Carb. 6 B.H.P.
Comp. Ratio. 4 B.H.P.
Cut Out. 7 B.H.P.

19 B.H.P. on 70 M.P.H.
or 37% increase.

At 80 M.P.H.
Carb. 11 B.H.P.
Comp Ratio. 4 B.H.P.
Cut Out. 7 B.H.P.

22 B.H.P. on 80 M.P.H.
or 50% increase.

As regards performance with these increased powers, 18-G-4 lapped Brooklands at 78.43 M.P.H. and did over the half mile with an average of 81.47 M.P.H. which is about what we shall get (S/52/MS.3.8.31.) In quoting Brooklands figures it should be noted that 18-G-4, our last 16,000 mile car has only a Brooklands lap speed of just over 70 M.P.H. and yet frequently ran up to 80 M.P.H. in France and a maximum of 84 M.P.H. actual was recorded under favourable conditions. It would therefore be fair to consider the proposed car with a lap speed of 80 M.P.H. as an 88 M.P.H. proposition.

The only alterations from 2-G-4 to give this result would be pistons, cut out control, and throttle edge slow runner on the carburetter.

HW/WH.

Attached : Ms.51.
  
  
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).


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