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).
Comparative power curve analysis between Buick type and standard Bentley pistons.
| Identifier | ExFiles\Box 134\1\ scan0061 | |
| Date | 21th December 1937 | |
| -2- I. BENTLEY Comparative power curves are shown in Fig.II, where it will be seen that for the same compression ratio, the dome pistons give a much lower power output than standard pistons. This was investigated by taking compression pressures and at the same time noting power on five cylinders for an estimation of mechanical efficiency. These latter figures, however, proved so inconsistent that they are not included, and it was not considered worth while repeating. An inspection of the pistons showed marks of rather hard bearing, due presumably to the greater piston weight and inertia loading (30% greater than standard), but the power loss is much more satisfactorily accounted for by a consideration of the compression pressures. FIG. II Graph Title: — BUICK TYPE PISTONS.— Graph Subtitle: OPEN EXHAUST POWER COMPARISON Graph Legend: BUICK PISTONS (C.R. = 7.42) STANDARD BENTLEY (C.R. = 6.42) BUICK PISTONS (C.R. = 6.42) Axes Labels: Y-axis (left): B.M.E.P. X-axis: R.P.M. Y-axis (right): B.H.P. Graph corner text: E.D. 2.12.37 continued | ||