FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

104 SMITHSONIAN ANNALS OF FLIGHT
FIGURE 1.—Interruption of a monergol explosion by safety
device.
fahrt [German Aeronautical Research Institute] in
Trauen, we worked very successfully with a thixotropic
monergole based on ammonium perchlorate
suspended with higher alcohols and certain soaps
in nitromethane. We could control this system and
overcome all the difficulties which had troubled us
in the 1930s.
Another possibility in our effort to find an engine
system as simple as possible was to place one propellant
component as a solid in the reaction chamber
and to inject the other as a liquid, gas or vapor. We
called such a system a "lithergole." It was necessary
to find a suitable arrangement in the chamber to
obtain reaction everywhere on the surface of the
solid. It was Andrussow who proposed putting the
fuel in the reaction chamber in the form of coal and
injecting the oxidizer in the form of nitrous oxide.
The cross section through an experimental engine
in Figure 2 shows the coal charge consisting of
single discs with holes drilled axially. As coal has a
very low thermal conductivity, the outer shell did
not need heat protection, and only the area nearest
to the circumference was left unperforated. We
ignited the system (see Figures 3-5) by means of a
Graphite Coal Soft coal
Gunpowder plate
Active coat
Injection nozzle
forN20
FIGURE 2.—Lithergol engine combustion chamber. Maximum
thrust was attained in 12 seconds.
FIGURE 3.—Simplified coal charges.
FIGURE 4.—Partly burned coal charge of a lithergol engine.