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 comparing actual test horsepower data with theoretical calculations, including a heat balance table for an unsupercharged engine.
| Identifier | ExFiles\Box 140\1\ scan0214 | |
| Date | 28th March 1938 guessed | |
| -10- Correlation of Actual Test Horsepower Data With Theoretical Calculations Over The Speed Range. It has been previously stated and will be more fully developed later that for the actual supercharged engine, employing a separately-driven air compressor, the work corresponding to the area 2-3-4-5-2 of the theoretical cycle shown in Figures 25A and 25B, which is the work derived from the energy released by the combustion of the charge, is equal to the sum of the measured brake output work and the measured work necessary to motor the engine at the speed and intake manifold pressure considered. Such work sums are represented by the horsepower data shown in Figure 17. The gains in power output due to supercharging the engine at 5.55 to 1 compression ratio and various speeds are compared with corresponding theoretical gains in Table III. The methods of calculating the theoretical gains for this table will be discussed in detail later. TABLE II. Heat Balance of Unsupercharged and Supercharged Engine. Distribution of Total Energy Supplied. Engine Speed R.P.M. | Percent Converted to Brake Work | Percent in Cooling Water. | Percent in Exhaust Gases, Radiation, and Unaccounted for. --- | --- | --- | --- 5.55 to 1 Compression Ratio Engine Unsupercharged 500 | 19.9 | 26.3 | 53.8 1,000 | 21.9 | 25.1 | 53.0 1,500 | 21.6 | 22.7 | 55.7 2,000 | 21.8 | 20.5 | 57.7 2,500 | 21.8 | 19.8 | 58.4 3,000 | 20.4 | 18.4 | 61.1 3,500 | 20.6 | 18.8 | 60.6 4,000 | 20.4 | 21.9 | 57.7 Continued. | ||