FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

NUMBER 10 105
FIGURE 5.—Lithergol combustion chamber.
small charge of gunpowder. The problem was to
cause a simultaneous reaction over the full length
of the intake so that the charge would burn off not
from one end to the other but radially. We solved
it by a lining of celluloid inside each hole, which
instantly heated the entire inside surface to ignition
temperature. In our experiments on the test
stand, full thrust could be reached within one second
and thrust oscillations could be reduced to less
than 5 percent. At that time we thought these simple
systems could be used for long burning times, although
we realized that the necessary diameter sets
a limit on the overall impulse.
At this point it is pertinent to remark on the
application of the oxidizer used in the lithergole
engine to increase the high-altitude output of piston
engines and pulse jets. Figure 6 shows an arrange-
-100
-E
^4^=133^-
*- m 9P
FIGURE 6.—Temperature distribution in the air intake to the
supercharger.
ment to inject the liquid nitrous oxide into the air
intake of the supercharger. In the graph is plotted
the temperature of the air for different oxidizers
and for injection before and behind the supercharger.
The cooling of the air results in a greater
mass flow into the cylinder. Figure 7 illustrates the
increase of the cylinder pressure due to the injection
of N20 and to varying the point of ignition. The
thermodynamic and physical properties of nitrous
oxide suit the requirements of a piston engine in
such a fortunate manner that the high altitude out-
87.5
75
BUS
50
37.5
25
12J5 — A
B Igniti on of b and c
-* |—10°
—- Vr^7.9
—
c
IT" k8 °
0
H B 120 90 60 30 TC 30 60 90 120 150
1 °KW
-A26"
-J7°-J
—
Nv
i No addition
b Addition of iMg/sectyO
cAddition of &60g/sec N70
Addition of 9.02g/sec N,0
L
90 120 150
'HW
FIGURE 7.—Pressure-time diagrams (T. C. = top center,
°KW = crankshaft angle).