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).
Report comparing the cooling systems and overheating issues of the 20 HP and 40/50 HP models, including notes on driver habits.
| Identifier | ExFiles\Box 24\4\ Scan195 | |
| Date | 25th August 1924 | |
| - 3 - BY17/H.{Arthur M. Hanbury - Head Complaints} 25.8.24. 20 HP. Cooling System. In BY21/H.{Arthur M. Hanbury - Head Complaints} 19.8.24. I did not suggest that the 20 HP is satisfactory. I stated definitely it is not, but I contended, and still do, that the 20 HP. has a very much smaller deficit against it than the 40/50 HP., a statement which embraces the fact that the 20 HP. is developing greater percentage of its power over any distance than does the 40/50 HP. In addition to having a smaller deficit in the direction of heat taken out of water as against heat added to water by the engine, I pointed out that much larger openings or passages for the air to escape from the bonnet are provided and that therefore the 20 HP. offers a much easier opportunity of solution than the 40/50. The overheating of neither 40/50 or 20 HP. cars occurs at much below full throttle, or to be more exact, under approximately full engine torque conditions. Use of Lower Gears. In Para. 5, Page 1, F.H. assumes that climbing on the gears will prevent boiling, but as pointed out in my report, this is not true if the throttle is held full open on each gear. It can be done if driver is content to drive on a less throttle when he drops to his lower gear, and not unless, and this is precisely what our awkward customers refuse to do. Incidentally, my remarks above are precisely similar to the argument in my report under discussion, which caused R.{Sir Henry Royce} to say in this connection I say "Yes" and "No". It is true I do, but with clearly outlined distinctions. BY.{R.W. Bailey - Chief Engineer} | ||