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).
Data table showing the loss of power due to the temperature of a hot spot at various RPMs.
| Identifier | ExFiles\Box 66\2\ scan0020 | |
| Date | 10th February 1925 guessed | |
| (2) LOSS OF POWER DUE TO TEMPERATURE OF HOT SPOT. Bar. 754.5 Temp. 18°C. R.P.M. | With ht. lbs. | Cold lbs. | Loss due to ht. lbs. | % loss due to heat. 2500 | 107.5 | 110 | 2.5 | 2.27 2250 | 118.5 | 121.5 | 3 | 2.48 2000 | 128 | 130.5 | 2.5 | 1.92 1750 | 135.5 | 135.5 | 2 | 1.475 1500 | 136 | 137.5 | 1.5 | 1.09 1250 | 139 | 142 | 3 | 2.1 (6) 1000 | 139.5 | 139.5 | --- | --- 750 | 143 | 141 | -2 | -1.42 650 | 145 | 142.5 | -2.5 | -1.75 | ||