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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).
Performance analysis detailing brake horsepower increases at various speeds and comparing results to Brooklands lap data.

Identifier  ExFiles\Box 56\3\  Scan034
Date  22th December 1931
  
-2- HS{Lord Ernest Hives - Chair}/Rnl/MA.22.12.31. cont'd

At 70 M.P.H.
Carb. 8 B.H.P.
Comp. Ratio. 4 B.H.P.
Cut Out. 7 B.H.P.
----------
19 B.H.P. on 70 B.H.P.
or 27% 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 B.H.P.
or 36% increase.

As regards performance with these increased powers, 12-G-4 lapped Brooklands at 73.43 M.P.H. and did 80.3 M.P.H. over the half mile with 39 Clutch B.H.P. which is about what we shall get (HS{Lord Ernest Hives - Chair}2/MJ.29.8.31.) In quoting Brooklands figures it should be noted that 18-G-4, our last 10,000 miles 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 85 M.P.H. proposition.

The only alterations from 20-G-4 to give this result would be pistons, cut out control, and throttle edge slow runner on the carburetter.

Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}

Attached : Rn.{Mr Robinson}61.
  
  


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