—Results are presented of detailed gas analysis traverses carried out within a gas turbine type research combustor. The combustor was run at approximately atmospheric pressure, and fuelled by propane vapour. Two sets of results are described; these were obtained by using two alternative fuel injector nozzles in an attempt to modify the degree of fuel-air mixing within the combustor. Detailed measurements on axial and radial planes within the combustor of quantities of interest in gas turbine combustion at idle (equivalence ratio, temperature, carbon monoxide and unburned hydrocarbon) are presented and discussed. Some molecular hydrogen measurements are also given.