Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-01-19
BY PHILIP r. WHEELER.

There is danger in a forced landing
for an inexperienced pilot, or when
landing under adverse conditions, but
such occurrences are becoming less and
less frequent. Both manufacturers and
the United States Government are do
ing research and experimental work d.
rected toward the building OF engines
which will be safe and dependable for
the public.
Human fight became possible with
the development of the gasoline en-
CINE. All other forms of prime movers
have been too heavy in relation to the
power developed. Herein lies the grief
of all designers. trying to reduce weight,
to chop off little metal here. little
there. and leave only just what Is nee
essary to give a safe and dependable
engine. Every part must have an am
pie factor of safety, yet no part should
weigh an unnecessary ounce.
The stresses in many structures can
be calculated with mathematical accu-
racy and the exact size and shape may
thus be determined, but those in a
complicated casting would almost defy
an Einstein. Naturally. with the cut
and-dry method, mistakes are made.
While the automobile engine had its
period of uncertain operation and i'm
provement toward reliability. the haz-
ards of failure in ground travel are not
quite like those of the air. This fact
may be hastily passed over or left I'M
considered by the aviation enthusiast.
but a healthy fear where 1t is needed
can do much to prevent mishaps.
Realizing the rapid change and many
developments being made in the field
of aviation engines. the Government
established system of testing whereby
the public would be protected. to a
large extent. from newly developed end
untried engines. The testing also helps
the manufacturers to locate bugs" and
to get the design perfected before in
stalling costly production machinery.
Here are some brief glimpses OF an
engine in the process of being tested:
Contact" calls the mechanic.
Contact" echoes back the operator.
The propeller Is turned and the en-
CINE starts. 1t is mounted on queer
looking steel structure with innumerable
wires, tubes and pipes leading to 1t
from the adjacent wall In is minutes,
If all goes we'll it will be running with
wide-open throttle. stu wide open at
the end of five hours. 1t will have COM
pleted the first lap of a 50-hour endur-
ance test.
The remaining As hours are run at
about 81 per cent Of full-throttle speed.
If still whole at the end of SO hours.
the engine is taken from the "torque
stand" carried to the shop and torn
down.
vital parts are measured with mi
crometers to 10000 of an inch.
Clearances and wear are noted. Cast
ing5 are closely examined for cracks
and other defects. Blue prints are
compared to see If they check with
actual construction.
On a hill in the outskirts of north
west Washington are the buildings of
the United States Bureau of Standards.
Here, in the offices Of the automotive
power plant section, the collected data
from the 50-hour run and from the
tear-down inspection ale examined and
worked into report.
Everything being favorable, certifi-
cate of approval Is issued by the aero
nautics branch of the Department OF
Commerce and the type of engine can
be used In licensed aircraft.
During the 50-hour run three forced
stops are allowed for what are termed
minor failures, such as broken valve
spring or a cracked porcelain in a
spark plug. A failure of any major
part of the engine, for instance, a crank
case, Immediately terminates the test
and eliminates possibility of approval
until the faulty part has been rede-
signed.
One day at the testing laboratory a
whole cylinder barrel, head, valves and
all, popped eff from a radial engine
and struck the concrete wall. Pistons
sometimes freeza. and have their heads
pushed cut Propellers have been
known to come off.
To guard against the danger Of these
flying missiles. the concrete blocks in
the wall on either side are reinforced
with steel rods and the hollow spaces
filled solid with cement. A small OBJ