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 for petrol and water boiling at high speeds on hot days, comparing inside and outside petrol pipes.
| Identifier | ExFiles\Box 91\1\ scan0364 | |
| Date | 27th June 1936 | |
| 102/ HOTEL DE FRANCE. CHATEAUROUX. Indre. France. GWH{George W. Hancock - Head Chateauroux}/HH/6/JAB. 27th June 1936 To E Clowes By MX{John H Maddocks - Chief Proving Officer} To. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} 32. EX. We have been able to carry out further tests with regard to petrol boiling at high speeds on hot days. We enclose a set of readings and show the point at which the outside pipe had to be fitted. The car was run using the inside petrol pipe, and recording the temperature inside the "V". The outside air temp. was 28°C and the highest under bonnet air during the run was, 70°C. Everything went well till we had completed 80 miles and then the car started to splutter & frequently felt wooly. We therefore decided to change over and replace the outside pipe. We continued our running and had no more trouble at all. The above results confirm our opinion that boiling during running takes place in the supply pipe and not in the carburetter, for had this been so, the engine would have continued to splutter, whereas it immediately ran without trouble & continued to do so for the remaining 110 miles as soon as the outside pipe was fitted. We enclose also a set of readings taken outside the "V" with the same average outside air temperature; this should give you a value for the outside pipe as compared with the inside pipe. We think it safe to say that with the use of the outside pipe and sufficient cooling of the petrol pumps, the average customer will not meet with any difficulty due to petrol vaporising in any form, unless he runs his car under extremely severe conditions i.e. outside air temperature of 30°c or more, and can maintain a high average speed over 60-100 miles. These figures include a set of water jacket readings, also radiator inlet readings. The water only boils after a fast prolonged run with an outside air temperature of 26°c and upwards. The radiator head was filled 1.1/2 inches above the bottom plate, before the run. We suggest that the front water passages in the blocks be stopped up in order to circulate the water more evenly, as has been done on B.56.BN.{W.O. Bentley / Mr Barrington} & 22.G.V. The above remarks should answer your query with regard to water boiling. ref. your memo. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}26/KW.25.6.36. ---------------- GWH{George W. Hancock - Head Chateauroux}/H.H. Hf.{H. W. Frost - Coachwork Inspector} Hamilton | ||