Evening star., 1940-06-11

expanding aircraft engine IdIluldC-
turers. But, while the aircraft en-
CINE producers, with their going
organizations and trained specialists.
can get plant additions Of almost
any necessary size into operation
within a year, it would require dou-
BILE that length of time to set up pro-
duction in a new plant or in a con-
verted automobile plant, it was
stated.
Because of their enormously
greater orSepower-more than ten
times that of the. average automobile
engine-and the necessity for very
light weight. parts of aircraft en-
gines are subjected to stresses Of
which the automobile engine maker
never dreams aircraft engineers
here pointed out. This calls for far
more precise machining methods
than the automobile engine manu-
facturers have had to consider for
almost every part Of an aircraft en-
gine and for machining tolerances
closer than great majority of au-
tomobile machine tools can follow
AS an example, it was pointed out
that automobile manufacturers
never have had any difficulty in OBJ
tanning gears of the types required
and that any competent gear manu-
facturer can turn out any of the
gears required in automotive pro-
duction But when the Pratt g.
Whitney engineers called upon the
gear industry for gears capable of
withstanding the loads imposed
upc<l the gears in a modern high
powered aircraft engine not a sim
gle gear company would undertake
to meet the requirements.
you can't build gears like that"
the gear company experts said. I'VE
can't produce gear that will stand
those loads or meet your tolerances."
Manufacture Own Gears.
The Pratt 81 Whitney engineers
had to design and manufacture
their own gears. They built, in the
subsidiary Pratt & Whitney ma
chine-tool factory west of Hartford,
machines capable of producing the
gears they required, and these new
precision gear-grinding machines.
without any parallel in the automo-
bile industry, are grinding gears out
OF special hard, tough steels within
tolerance of one-ten-thousandth OF
an inch for aircraft engines.
This Is but one of many special
lied problems the aircraft engine
makers have had to solve. In doing
so they have created an ever
widening gulf between their own
methods and machinery and those
of the automotive industry. This is
why it would require the complete
retooling of an automobile plant to
put it into aircraft engine produce
ton. An almost complete retraining
of the automobile factory personnel
also would be necessary, in the
opinion of aircraft engine manu-
facturers.
The aircraft engine industry
never has been put on a mass pro-
duction basis at all comparable with
that of the automobile engine busi-
ness. Many entirely new types Of
specialized machine tools would be
required to put even the most COM
pletely fooled aircraft engine
plant into Zine production" meth
DDS as they are understood In the
automobile industry.
There are, however, constant i'm
provements in methods and machine
tools in progress in the Pratt &
Whitney plant here. Five separate
machining operations must take
place inside the cylinder head of the
aircraft engine. The best machine
methods available a year ago re-
quired II minutes for this work.
There now is in operation in the
newly completed s12 900 900 so-called
French" addition to the Pratt &
Whitney factory, built during the
past year to speed up production of
engines for French warplanes, an
entirely new type Of machine which
performs the five operations, in sue
cessive stages, in 3 minutes 5 Sec
onds.
New Methods Developed.
Among the many interesting new
methods of treating engine parts
developed here which are unique to
the aircraft engine field is the pro-
tective coating of cylinders which
will be subjected to the corrosive
influences of salt air and water.
Instead of being painted, they are
sprayed with molten aluminium, fed
into the spraying machine in the
form of wire.
Because lives depend upon the
perfect functioning of an aircraft
engine, every engine produced here
is put through Is hours Of operation
before leaving the plant. For the