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).
Letter explaining discrepancies in road test temperature readings and proposing a new reporting method.
| Identifier | ExFiles\Box 11\3\ 03-page086 | |
| Date | 7th May 1930 | |
| To: Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From G.W.H. X7940. Hôtel de France, Châteauroux, Indre. 7/5/30 We have received your letter Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}7/MJ.5/5/30. We agree with you that our remarks are misleading. The explanation is that on 30/4/30, when the air temperature was 23° and the water temperature 90°, was an afternoon's run only, when the average air temperature is much higher than when you take the morning and afternoon averages. There are also many snags in water temperatures and air temperatures on the road, for example I was out on the car the other morning when the air temperature was round about 17° and on the run out the water temperature was at an average of 75°. On turning round, the air temperature was still the same, but my water temperature immediately went up to 89/90°. It is all a question of whether you have a following wind, or side wind, or a wind dead against you. It does not necessarily mean that the air temperature will vary. These remarks will perhaps explain the difficulties in giving exact comparisons of water and air temperatures. You will notice that, in to-day's Daily Report, I am giving the maximum air temperature and the maximum water temperature. In future, we will do this as we believe it will be less confusing. We are also giving you the average for the day. We have not had any further definitely high temperatures or loss of water from the radiator. The weather has been much more variable and has not maintained the heat throughout the day, as we happened to have for two or three days when the trouble arose. We are still of the opinion however that with a steady high air temperature with no wind, there will be difficulties in keeping the engine cool at any high speed. | ||