Evening star., 1952-04-16
Delicate Machine Parts
CIeonedbySoundWoves
General Electric Co. Reports
On Tests in Own Plants
By Thomos R. Henry

By Thomas R. Henry
Ultrasound waves now are being used
as means of cleaning small parts of
delicate machines that cannot be
reached in any other way except by
tearing the mechanism apart.
UltraSonic cleansing. according to
the March Review of the General Electric
Co., provides a method of removing
"oll. grease, chips and dirt from the
surfaces of small precision pieces at a
rate hitherto unattainable and to a de-
gree OF cleanliness which surpaSses the
most stringent industrial standard"
This is accomplished by beaming a
hlgh-frequency sound wave through
cleansing, solvent to the surface of the
submerged part which it Is desired to
clean.
For some time to come, according to
the General Electric statement, the
system will be rather expensive and
difficult to install and will be justified
mainly for professionally work pieces
having a. high intrinsic value per cubic
inch and requiring a really thorough
cleaning.
Superlative Claims Made.
But within these limitations we can
make superlative claims for the method.
1t is applicable to pieces of almost any
material - metals, glass, textiles or
nodded products-and to parts of al
most any conceivable shape. We may
even say the more irregular the shape
the better. UltraSonics is particularly
good for getting at blind holes and
Honilloru
sible in the choice of solvent solutions
or detergents. The liquid medium must,
OF course, be compatible with the ma
terlal OF the workpiece and will usually
be one which would accomplish a par
tial cleaning without ultrasonics.
"We' confidently predict that the
present decade will see many more such
installations saving untold thousands
OF manufacturing dollars"
The ultraSonic cleaners, it is ex-
planned, were first developed for use in
the General Electric Co.'S own factories
and no effort has been made to extend
their use. Several other manufacturers.
notably the Fairchild Camera Co., how
ever have adopted them and several
others are considering installations.
Speeds approaching 1000 miles per
hour are attainable by tactical military
aircraft In the foreSeeable future
But now standing in the way of such
speeds, which would carry one around
the world between sunrise and SUM-
set, are formidable barriers-most i'm
portant OF which is heat wall"
Means OF crossing this wall" now are
major concern of aeronautical re-
search, according to John F.. Victory.
executive secretary of the National Ad-
Vlsory Committee for Aeronautics. In
the end. he believes, it may not prove
more formidable than that much
feared sonic wall" of few years ago
which was supposed strictly to limit
plane speed to approximately that of
sound. This was crossed successfully for
the first time five years ago.
This "heat WALL Is due to the enor-
nous increase in temperature due to
friction OF the atmosphere against a
planes outer surface. At about $500
miles per hour at sea level the surface
temperature would rise to about ATS
Fahrenheit. Even in the thin atmosphere
eight to ten miles above the earth it
would rise to approximately $50 Fahren-
heit.
At ATS degrees the aluminium ALLOW
commonly used in the manufacture of
airplanes loses about 40 per cent of its
strength. Under the enormous stresses
involved the plane probably would fall
to pieces.
Two Materials Hold Promise.
Research conducted to date" Mr..
victory said, indicates that two ma
terials hold real promise for use in
future aircraft construction. One is
stainless steel, which has good strength
advantages. especially at temper
atures above 800. The other is titanium.
which has been found to have good
strength properties in the intermediate
temperature range. from 600 down.
ward. Another possible solution may be
the use of insulation inside the airplane
skin, which probably will require de-
Velopment Of new types of structure.
Then 1t will be necessary to provide
very efficient refrigeration equipment
to keep the pilot from being roasted
alive, and temperature sensitive elec-
tronic equipment from being baked to a
crisp. Still another problem demanding
solution Is how to cool, or otherwise
protect, non-metallic materials now used
IN alrplanes. such as the plastics used in
Windshields."
At 1,500 miles an hour and above, Mr..
Victory said, the ram-jet type of pro-
pulsion probably will be used but its
performance is greatly affected by the
altitude and speed at which the plane
is flying.
1T would be relatively simple" he
said, ito build a ram-jet to operate
efficiently at only one altitude and one
speed. Research now is being conducted
to make the ram-jet more flexible in
operation"