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).
Test report on carburetter water jacketing, fuel temperatures, and flooding causes.
| Identifier | ExFiles\Box 179b\3\ img046 | |
| Date | 17th January 1931 | |
| -4- Es/Zms.7/CT.17.1.31. It would appear from the tests that full bore water jacketing of the carburetter is only detrimental to the running of the engine by richening up the slow running mixture, and causing unstable running by the fuel boiling off and gassing, which supplements the low speed jet by taking a gaseous mixture past the throttles, but when the engine is opened up from this position, the mixture is excessively rich while clearing the heated diffusers, and then cuts out due to weakness as the diffuser wells fill with cooler fuel, to commence to function in the normal manner. With full bore system the water temperature drop across the carb. jackets is 69°C and the fuel reaches 57°C and when restricted by .125 orifice the temperature drop is 16°C, and in this case the fuel temperature does not exceed 28°C, owing to the considerably reduced water flow and consequently less heat dissipated. The tests have proved that carburetter flooding is not caused by fuel boiling, but the flooding trouble which occurs after a backfire is a subject which is dealt with in a separate report. Es/G.H.Farmer. | ||