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).
Fuel tests comparing Shell Aviation B against standard petrol and benzol mixtures for engine detonation, condensation, and pre-ignition.
| Identifier | ExFiles\Box 32\1\ Scan051 | |
| Date | 5th April 1919 guessed | |
| -2- sign of condensation shewed up on the cold steel plate. With Shell Aviation B there is not the least sign of condensation on the steel plate until the water temperature in the cylinder jacket was at 39°C. With the standard spirit we use for testing, with the water in the jacket at boiling point there was obvious condensation and with the water in the jacket at 40°C, liquid petrol was dripping from the exhaust port. We have also carried out further tests and compared it with benzol and benzol mixture as regards detonations and pre-ignition. We find that on an engine where detonations with ordinary petrol are very bad, that they are completely cured if we run on Shell Aviation B. We also find that with a mixture of 50% Shell Aviation B and 50% ordinary petrol it is excellent as regards absence of detonations. From our tests we estimate that a mixture of 50% Shell Aviation B and 50% ordinary petrol is as good as 25% benzol and 75% ordinary petrol as regards preventing detonations. The point we wish to make very clear is the difference between pre-ignition and detonation, for instance, although a mixture of 20% benzol and ordinary petrol will absolutely eliminate detonation on certain engines it is not the best fuel as regards preventing pre-ignition. The very best thing we know of to prevent pre-ignition is 100% benzol but there are several well-known disadvantages in using all benzol. We admit the claims that Shell Aviation B is much better from every point of view than a mixture of ordinary petrol and 20% benzol. Our tests have shewn, however, that Shell Aviation B is still.slight-ly improved as regards possibility of pre-ignition if. A.{Mr Adams}(S) is added to the fuel (Contd.) | ||