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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).
Test data sheet showing thermal efficiency, power, and heat balance for a low compression test engine at various RPMs.

Identifier  ExFiles\Box 24\4\  Scan093
Date  6th September 1923 guessed
  
SHEET 2. LOW COMPRESSION (PRESENT STD)

THERMAL EFFICIENCY, POWER ETC. OF THE 40/50 RR. TEST ENGINE.
COMPRESSION RATIO 3.9 - ENGINE CLEAN - FUEL 'SHELL' NO.2.
S.G. .752. CAL.{Mr Calvert} VALUE (LOWER) 19.000 B.Th.U's/LB.

First Table:
| R.P.M. | Fuel pts. hr. | Pts. HP. hr. | B.H.P. | I.H.P. | HP. req. drive motor. | Jacket water. °C Inlet. | Jacket water. °C Outlet. | Lbs. water min. | B.Th.U's. min. to water. | Mech. effcy. |
|---|---|---|---|---|---|---|---|---|---|---|
| 500 | 18.09 | 0.78 | 23.1 | | 4 | 57.75 | 80 | 41 | 1660 | |
| 750 | 26.27 | 0.78 | 33.67 | | 5.5 | 58 | 78 | 62.5 | 2250 | |
| 1000 | 32.14 | 0.706 | 45.42 | | 8 | 61 | 81 | 82.5 | 2970 | |
| 1250 | 40.45 | 0.71 | 56.75 | | 11.5 | 64.5 | 81.5 | 103.5 | 3167 | |
| 1500 | 46.75 | 0.70 | 66.25 | | 15.5 | 65 | 80 | 126 | 3402 | |
| 1750 | 52.9 | 0.71 | 74.75 | | 20 | 66.5 | 80.5 | 150 | 3780 | |
| 2000 | 58.53 | 0.75 | 77.29 | | 26 | 70.5 | 83 | 177 | 3982 | |

HEAT BALANCE.

Second Table:
| R.P.M. | 500 | 750 | 1000 | 1250 | 1500 | 1750 | 2000 |
|---|---|---|---|---|---|---|---|
| Thermal equt. work done. | 980 | 1428 | 1927 | 2407 | 2809 | 3171 | 3278 |
| Loss to engine friction. | 169 | 233 | 339 | 488 | 636 | 847 | 1103 |
| Heat loss to jackets. | 1660 | 2250 | 2970 | 3167 | 3402 | 3780 | 3982 |
| Ht. loss through exh. & radiation by difference. | 2577 | 3909 | 4332 | 5978 | 7073 | 7952 | 9067 |
| Heat supplied. | 5386 | 7820 | 9568 | 12040 | 13920 | 15750 | 17430 |
  
  


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