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).
The investigation of boiling in Large Bore 20/25 models due to radiator shutters not opening at high speeds.
| Identifier | ExFiles\Box 105\1\ scan0245 | |
| Date | 6th February 1936 | |
| To E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Sft.{Mr Swift} 7540 Hs{Lord Ernest Hives - Chair}/Std.6/KW.6.2.36. Boiling of Large Bore 20/25 due to Shutters not opening at High Speeds. This trouble, reported by Hancock on 21-C-IV, has been investigated on 18-G-IV, GUB-5 and GAE-20 (the last having a small bore engine). The manner of testing was to run the car until a water temperature of approx. 70°C. was attained, the shutters being closed at this temperature, and then drive the car at maximum speed and throttle opening for about 2 1/2 to 3 miles on the Six Hills road, observing the water temperature (cyl. block) at which the shutters opened. The opening temperatures observed in the case of the three cars were :- (1) 18-G-IV. 90°C. (2) GUB-5. 85°C. (3) GAE-20. 88°C. GAE-20 was also tested with a calorstat spring to E83210 fitted. This gave an opening temperature of 93°C. The average running temperatures noted were as follows :- (1) 18-G-IV - no calorstat spring - 72°C. (2) GUB-5 - " " " - 71°C. (3) GAE-20 - " " " - 74°C. (4) GUB-5. - With calorstat spring- 80°C. (5) GAE-20 - " " " - 80°C. | ||