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. | ||