A copolymer consisting of the combination of the LP-33 polysulfide and hydroxyl terminated polybutadiene is produced as a candidate low ignition temperature ramjet fuel. The objective of the copolymerization of the materials is to combine the low decomposition and autoignition characteristics of the sulfur based LP-33 with the high heat of combustion per unit mass of the HTPB. Dynamic mechanical analysis and differential scanning calorimetry data for the copolymer show that the glass transition temperature is loweras compared to the LP-33 formulation. Storage modulus values are found to be within acceptable ranges with the copolymer showing an improvement in the storage modulus over the LP-33 formulation at ambient and above temperatures. Thermogravimetric analysis demonstrates that the onset of decomposition of the copolymer does not deviate significantly from the LP-33 preserving the desired low decomposition characteristics. Pipe combustor data demonstrates that the mass burning rate of the copolymer has very similar and predictable characteristics as a function of the heating rate when compared to the monopolymers' formulations. Analysis of the combustor data shows that the copolymer has improved performance over the LP-33 monopolymer at high inlet momentum values. Published by Elsevier Inc. on behalf of The Combustion Institute.