Because of its simple construction and low weight, combined rocket, ramjet, pulse-jet engines, or detonation enginesinsteadofturbojets,weretakenintoconsiderationaspropulsionforhypersonicaircraft.Combinedpropulsion requires an active control system to change the propulsion operation mode and to sustain the high-efe cient pulse combustion. Therefore, the transient behavior of the combustor is investigated to show the benee ts that can be gained, especially from a pulse combustor with active control. Several experiments were performed to survey system performance and to e nd suitable control parameters and strategies. Propulsion installation, including thrust augmentation, is considered to dee ne the tasks of the combustor controller. Nomenclature A = cross section b = fuel consumption c = sound velocity D = pipe diameter F = thrust f = frequency H = net calorie c value L = tail pipe length M = Mach number C m = mass e ow n = rotational speed P = pressure Re = Reynolds number T = temperature t = time u = velocity X, Y = coordinates a = angle of attack D P = pressure amplitude g = efeciency j = ratio of specie c heats q = density Subscripts and Superscripts