(Page 100, Astronautics, September 1958) "Spontaneous combustion may be obtained by contacting furfural with solid permanganates of many metals, and also with sufficiently concentrated permanganate solutions. Since permanganates in aqueous solution may be introduced conveniently into a reaction zone, those which have a high solubility in water are preferred.

Permanganates which form solutions sufficiently strong to burn furfural spontaneously include those of calcium, aluminum, sodium, magnesium and barium. Others, including potassium permanganate, which are not sufficiently soluble in water, may be employed in the solid state, or, in some cases, as concentrated solutions in other solvents.

The manganese dioxide and other metallic oxides formed through the spontaneous combustion of furfural and permanganates are, especially as freshly formed, active catalysts of a variety of nitroparaffins. The invention contemplates the formation of manganese oxide in the combustion chamber through the reaction of furfural with a permanganate, and the catalysis of a principle gas-producing reaction -- say, the combustion of a nitroparaffin -- in the chamber by the oxide thus formed, and the use of predeposited solid permanganate in the chamber for the same purpose.

In motor operation, the outlet valves of the combustion chamber are set for proper flow rates of the furfural, permanganate and main propellant. The furfural and permanganate may be introduced simultaneously in advance of the main propellant, so that the spontaneous combustion of the first two establish proper conditions for ignition of the third.

Injection of the main propellant may be omitted and the jet created by reaction of the furfural and permanganate alone. Preferred practice is to inject all substances simultaneously, relying upon the reaction of the furfural and permanganate to ignite the main propellant, which might be a self-combustible mixture of nitroethane and nitromethane.

The catalytic effect may be prolonged and enhanced, especially if the supply of furfural and permanganate is interrupted after combustion of the main is initiated, by providing means for catching and holding some of the oxides within the combustion chamber. Normally, some of the oxides tend to accumulate on the chamber walls near the nozzle, and this effect can be enhanced by providing baffles or catching surfaces within the chamber. A set of baffles, in the form of small annular serrations on the wall of the reaction chamber, interferes little with passage of the jet while providing surfaces for collection of solid oxides. Baffles are formed by cutting annular grooves around the inner periphery of the chamber, and in section appear as a series of saw teeth. In practice, it has been found that ordinary rough lathe markings serve to catch a catalytic layer adequate in many instances."