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).
Table showing heat distribution as a percentage of initial heat supply at various engine RPMs.
| Identifier | WestWitteringFiles\K\September1923\ Scan25 | |
| Date | 12th July 1923 guessed | |
| SHEET 1. CONTD:- HEAT DISTRIBUTION AS PERCENTAGE OF INITIAL HEAT SUPPLY. R.P.M. | 500 | 1000 | 1500 | 2000 Thermal equt. of work done. | 18.3 | 19.90 | 20.45 | 19.8 Loss to engine friction. | 3.7 | 3.35 | 4.4 | 6.3 Heat loss to jackets. | 31.3 | 23.65 | 24.5 | 22.2 Loss through exhaust radiation etc. (by difference) | 46.7 | 53.10 | 50.7 | 51.7 Heat supplied. | 100 | 100 | 100 | 100 | ||