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 a percentage correction to Brake Horsepower (B.HP).
| Identifier | ExFiles\Box 37\3\ scan 110 | |
| Date | 9th August 1917 | |
| R.R. 238 A (770 H.{Arthur M. Hanbury - Head Complaints}-S.D. 442. 9-8-17) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1965 Contd. -4- b = Bo - B = 19/17 (Io - I) = 19/17 I. Hence the % correction to the B.H.P. = 100 b/B = 100 * (19/17 I) / ((19I - 200)/17) = 100 * 19 I / (19 I - 200) = 100 * 1/I { 1 - 200/19I }^-1 = 100 * 1/I { 1 + 2/19 } approx. since I = 100 nearly. = 21/19 x 100/I + [text struck through] = 21/19 x ( .1316 p + .1831 t ) ~= .15 p + .20 t (nearly enough for practical purposes). Example. If P = 740mm. and t = 20°C. then p = 20 and t = 20 and the % correction to the B.H.P. is 3.0 + 4.0 = 7.0 so that every 100 B.H.P. corrects to 107.0 B.H.P. at N.T.P. EFC. | ||