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).
Tests on Bentley radiator shutters that fail to open correctly in cold weather at high speeds.
| Identifier | ExFiles\Box 39\4\ Scan337 | |
| Date | 8th December 1933 | |
| Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/FD.{Frank Dodd - Bodies} X3499. 8.12.33. BENTLEY RADIATOR SHUTTERS. Trouble has been experienced on 1.B.IV. car at present running 10,000 miles in France, the radiator shutters not opening after being closed through water temperature drop. Under the present extreme cold weather conditions the water temperature drops below normal when the car is slowed down when passing through a town or village. Where conditions permit full throttle to be maintained for 3 or 4 miles at speeds of 80 - 90 M.P.H. the wind pressure on the closed shutters is too great for the thermostat to re-open them until a water temperature of 90°C is reached. The shutters are then fully open, the water temperature then dropping down to normal. Wind pressure and speed have no closing effect on the shutters in the fully open position. We have carried out a series of tests here reproducing the above conditions as far as possible, in order to prove whether the thermostat is working efficiently or not. The shutters used were standard but the thermostat was made by the Packless Gland Co. the same type as fitted to 1.B.IV. With the thermostat out of commision a spring balance was connected to the shutters to ascertain what poundage is required to hold the shutters in either a quarter, half, or three quarter open position. A poundage of 28 lbs. is required on the present production lever which is only 1.1875" long. In our test we used a lever double the length - i.e. 2.375" long, and 14 lbs. was necessary. To prove this test we ran with the shutters closed at 90 M.P.H. until 90°C water temp. was reached and then half opened the shutters while still maintaining 90 M.P.H. The temperature then slowly dropped back to normal showing the shutters to be held open effectively enough to overcome all resistance from speed and wind pressure. The fall in temperature with shutters only half open is explained by the very cold running conditions now prevalent. The results shew that the present thermostat arrangement is not efficient enough for extreme cold running conditions, combined with high speed, as the variation in temp. is too great. Hs{Lord Ernest Hives - Chair}/F.Dodd. | ||