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 calculations for correcting the pressure under a car's bonnet based on speed and rig conditions.
| Identifier | ExFiles\Box 149a\2\ scan0262 | |
| Date | 6th November 1935 | |
| (Appendix - Sheet 2) Hs{Lord Ernest Hives - Chair}/Std.14/KW.6.11.35. Correction for pressure under bonnet :- For car speed of 85 m.p.h. equiv. dynamic head = (.070 x 124.7 x 27.7) / (64.4 x 144) = 3.250 " H2O Total head in front of matrix = 3.250 + Pa{Mr Paterson} where Pa{Mr Paterson} = atmos. pressure. From sheet 5 , air vel. at exit from matrix = 35 ft/sec. equiv. dynamic head = (.070 x 35^2 x 27.7) / (64.4 x 144) = .26 " H2O From tests on car (also see App. sheet 6 <strikethrough>) (See Sheet 7) total head under bonnet = Pa{Mr Paterson} + .67" H2O Difference of total head 3.250 - .670 (under running conditions) = 2.580 " H2O Difference of total head under rig conditions = 3.250 - .260 = 2.990 " H2O. | ||