The steady state catalytic combustion of fuel borne air, Rowing parallel to a catalytic fin surface, has been studied. Experimental studies determined the temperature profiles of a catalytic fin when heat is extracted from the fin by a heat sink at the fin edge. A mathematical model of the catalytic tin was developed from the basic equations of change and the model predictions of fin temperature are compared with experimental results with combustion of propane or carbon monoxide fuel/air mixtures over a platinum/alumina catalyst. The heat fluxes from the fin to the heat sink were calculated and the effect of process variables on this are reported.