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).
Cooling efficiency tests conducted on hills around Clermont-Ferrand, France.
| Identifier | ExFiles\Box 5a\2\ 02-page119 | |
| Date | 26th June 1929 | |
| XE X58400 Hôtel de France, Châteauroux, Indre. From: C.W.H. C to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} R.{Sir Henry Royce} 26/6/29 We received your telegram to carry our tests on the hills round Clermont-Ferrand. We proceeded there yesterday and to make the tests as reliable as possible the four testers went with me, thus loading the car to its maximum. The weather unfortunately has cooled down considerably, at no time was the air temperature more than 15°C. On the way to Clermont-Ferrand we had one or two steady climbs at 30 M.P.H. top gear. On each of these climbs the water temperature was brought up to 90°C, at the bottom, during the climb and at the finish it had dropped to 75°C. These were approx. 2 miles in length. Upon arriving at Clermont-Ferrand we took the route to Mont-Dore, this appearing to be the severest by the map, alt. 1050 metres. It is a steady climb the whole way, but at no time was the engine taxed its full power. I slowed down to 10 M.P.H. several times, but the engine was equal to it and very quickly regained a normal speed. The water temperature during these trials never rose above 75°C. over a distance of 40 miles, the air temperature meanwhile had dropped to 10°C. I eventually found one hill approx. three miles long which the car would just not do in top gear. The speed for some distance was 20 M.P.H. in top gear. The water temperature gradually built up to 85°C., air temperature 12°C, but upon changing into third it immediately dropped to 75°C. On the return journey I tried the third gear whilst climbing, speed 40 M.P.H. the highest water temperature was then obtained, 90°C. being reached, air temperature 13°C. In this case however the hill could have been negotiated in top gear. The tests proved that under all normal conditions the cooling efficiency is all that could be desired. The extra power of the engine makes it almost top gear work for any main route over the mountains. Our high speeds tests during extreme hot weather, 30° - 35°C. in the shade, at no time has the water temperature rose above 85°C. CWH | ||