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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).
Page of airflow calculations and formulas for a Bentley engine.

Identifier  ExFiles\Box 17\6\  Scan149
Date  24th August 1933 guessed
  
-6-

Bentley :-

From similar calculations - assuming vol. efficiency approx. same as Phantom, the following air flows were obtained.

3500 - V₂ = 118.4 cu.ft/sec. (full valve lift.)
3750 - V₂ = 127.0 cu.ft/sec. (full valve lift.)
4000 - V₂ = 135.5 cu.ft/sec. (full valve lift.)
4250 - V₂ = 144.0 cu.ft/sec. (full valve lift.)
4500 - V₂ = 152.4 cu.ft/sec. ( ... )

(3) Calculation of air flow through port from pressure differences and temperatures measured.

For the type of metering nozzle used, the formula for mass flow is W = CK{Mr Clark} P₁ / √T₁

P₁ and T₁ be absolute pressure and temperature on high pressure side of nozzle, and C being a constant for any particular nozzle and K being a number dependent on the pressure difference across nozzle and obtained from calibration chart of nozzle.

Mass flow = W = K P₁ / √T₁ = 22.34 K P₁ / √T₁ (C = 22.34 for 1" nozzle used for all tests except 8 litre Bentley.)

If (3) refers to point at entry to port.

Density at (3) = P₃ / RT₃ lbs/cu.ft.
  
  


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