Evening star., 1940-10-11
Plane Parts UNDERGO
Grue|ing Tests
In Buffalo Factory
Bell Airoeobro Castings
x-Royed and Disseeted
To Prove Soundness
By JOSEPH S. EDGERTON,
Star Aviation Editor.

Star AVIATION Edltor.
BUFFALO, NY, Oct. 11.-Tech-
niques of the surgeon, the chemist
and the bridge builder are being
compounded in the modern airplane
factory to guarantee the soundness
and strength of the warplanes fight
ing the battle of Britain and going
into the air defenses of America.
Visitors with sufficient creden-
tials to get them past wartime
barbed wire and armed guards into
the plant of the Bell Aircraft Corp.
here are shown, among other things,
an X-ray laboratory which would
be the envy of the finest hospital.
They are shown a chemical lab
oratory as large as many small fac
tories. They are shown hydraulic
compressors with a load range up
to 100000 pounds, capable of smash
ing the toughest of small castings.
There are other machines and pro-
cesses capable of revealing secrets
of metal parts down to the bare
atomic componentS.
These processes are typical of
those which are being employed
throughout the aircraft industry.
They are becoming absolutely in
dispensable as greater speeds, the
shocks of higher horsepower and of
more powerful guns and the stresses
of modern operations impose more
and more loads on every part Of the
airplane structure.
Critical X-Ray Tests.
Every casting which goes into the
newest aerial thunderbolt-the Bell
Airacobra single scatter interceptor
pursuit airplane-must pass an
X-ray examination as critical as
that the surgeon gives his star pa
tient. Not only is every casting sub
jected to X-ray examination from
all angles, but the results of these
tests are recorded on film and the
films are examined microscopically
This treatment gives complete
history of conditions existing within
the casting-a history which can be
obtained in no other way short of
destruction of the casting Any de-
feet. whether it be a gas pocket
smaller than the head of a pin, a
thin crack entirely within the metal,
or even a small area where the me-
tallic alloys are not evenly distrib-
uted. shows up in the film
Not only are the films examined
microscopically; they are subjected
to other sensitive optical instru-
ments, such as the micro-denitom-
eter, device which checks the den-
sity Of the X-ray negative itself. so
that not only the original casting.
but the Photographic recording of
that casting as well, is checked for
flaws.
No casting escapes this searching
scrutiny.
Sample Castings Dissected.
But, In addition, sample castings
are taken at random from among
patches of castings at regular in
tervals for even more dtailed tests.
These sample castings are cut up
into sections. One section may be
immersed in salt spray for hours
and days to determine its ability to
withstand corrosion. The brine sets
up thousands of minute galvanic
batteries over the entire casting sur
face, so that small currents pass
back and forth between crystals and
atoms of one element and another.
Galvanometers so sensitive that they
can measure the number of electrons
moving from point to point within
the metal are used to gauge the
potential strength of the casting in
its battle with wind, rain and ad-
verse weather conditions.
Another piece of the casting goes
into the jaws of the compressor and
is squeezed to destruction by ma
chine which, although it can gen.
crate forces equal to $50 tons of
dead weight, can be controlled and
measured by mechanisms as fine
and delicate as the finest Swiss
watch.
A third piece may be pulled
asunder by another operation just
as delicately controlled and meas
ured
A fourth goes into an impact
tester. This is a pendulum-like af-
fair which strikes the specimen a
tremendous jolt and measures the
energy required to break the metal
under sudden, heavy blows.
Atotmic Design Checked.
Other samples are routed to the
chemical laboratory to be analyzed
for possible faulty composition, while
the crystalline structure is scanned
by microscope to check the pattern
of the atomic building blocks of
which all matter is composed.
Elsewhere in the laboratory the
visitor sees furnace for hardening
metals, delicate instrument for