Abstract: A rocket motor construction wherein a convolutely wound propellent strip forms a fuel grain disposed within the rocket motor casing. The fuel grain consists essentially of double base propellent having a plateau or mesa burn characteristic and is shaped to provide a plurality of rearwardly extending blades connected to a convolutely wound margin of the strip. The blades cooperate with each other and with the rocket motor casing to define flow channels between angularly adjacent blades and between adjacent convolutions thereby providing flow channels for combustion product.