A French Conference: Summaries of Papers Read at the Annual Meeting of the Association Technique Maritime et Aeronautique

An account of tests carried out at Chalais Meudon for the purpose of investigating the detonating properties of fuels by means of a new calorimetric method which only requires measurements of the heat acquired by the cooling water in the cylinder jackets. The plant used includes a single‐cylinder laboratory engine designed by the Ethyl Gasoline Corporation for investigations of knocking by the Midgley method, but adapted at Chalais for measurements of temperature, and a 250‐h.p. six‐cylinder engine to normal aero‐engine design with special apparatus for the delivery and collection of the cooling water enabling accurate gauging of quantities and heat In addition, tests have also been carried out with a 450‐h p. aero‐engine, the special advantage of the calorimetric method being that investigations of fuels can be effected directly on the engine in which the fuel is to be used. The fuels investigated in the tests reported on were mixtures of petrol with benzol in quantities varying from 10 per cent to 40 per cent, or petrol with small admixtures of fluid ethyl (tetra‐ethyl of lead) or iron carbonyl. It was found that the addition of 40 per cent benzol or of 0·775 per cent ethyl fluid had the same effect as regards elimination of knocking.