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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 estimations calculating the effect of increased horsepower, or reduced frontal area and weight, on maximum speed.

Identifier  ExFiles\Box 161\1\  scan0253
Date  22th December 1938
  
also HOD.

To Rm.{William Robotham - Chief Engineer}
COPY FOR FILES.

Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}22/JH.22.12.38.

Given a max. lap speed of 88 m.p.h. with 128 clutch B.H.P. it is estimated that 160 clutch B.H.P. would give an increase of 7½% i.e. to 94¾ m.p.h.

Assuming,

Frontal area of car 24 sq.ft.
Total weight with two passengers. 1.84 tons.
Tyre pressures. 35 lbs/in².

..................

As a point of interest this is equivalent to reducing the frontal area (K being assumed unchanged) by 24% i.e. to 18¼ sq.ft.

..................

Reduction of 1 sq.ft. would give a speed gain of 1 m.p.h, which same result would require a reduction in weight by 21% i.e. to 1.45 tons.

..................

Rm{William Robotham - Chief Engineer}/T.A.Swinden.
  
  


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