Evening star., 1941-05-18
By Joseph s. Edeerton.

By Joseph s. Edeerfon.
With the knowledge that in mechan-
lied world conflict, concentrated brute
horsepower may prove the key to victory,
the Army Air Corps, in cooperation with
the National Advisory Committee for
Aeronautics and the American aviation
industry, is pressing the development of
bigger aircraft engines than the world
has seen to serve as the power plants
for faster and larger airplanes than any
known today.
Although it is only within recent
months that the 2,0O0-horsepower air
plane engine has become available, the
Air Corps already is looking forward
TO an engine capable of delivering 5000
horsepower. At the Air Corps Materiel
Division, Wright Field, Ohio, installation
Of the test stand for the 8,000-horse-
power engine already is under construc-
ton.
The Materiel Division is becoming the
home of horsepower. In addition to the
research program in giant airplane en-
gines, the Air Corps now is completing
construction at Wright Field of a So $780,
900 high-speed wind tunnel to be de-
voted exclusively to military applied re-
search. This wind tunnel is powered
with a single 40 900 horsepower electric
motor more powerful than the total
power plant installation of the S. S.
America, the largest steamer built in the
New World, and far more powerful than
the power plants of the largest United
States battleships.
Expanded Research Facilities.
The National Advisory Committee for
Aeronautics also is building an $8,400,0 900
aviation engine research laboratory at
Cleveland, Ohio, and greatly expanded
research facilities at its aeronautical
laboratory at Langley Field, Va, and the
new California Laboratory at Moffett
Field, Sunnyvale.
Army Air Corps research experts at
Wright Field said that they already are
looking forward to the day when air.
plane power plants of up to 5000 horse
power will be ready for acceptance tests.
New power plant test equipment now
being assembled at Wright Field has
been designed with this goal in mind,
and when the big engines are ready, as
engineers are confident they eventually
will be, the equipment here will be heavy
enough and strong enough to perform
the necessary tests" it was said in an
official report from the Materiel Division.
An 5000 horsepower engine would
equal the total power installation OF a
10,0OO-ton steamship, usually composed
of at least two engines driving two pro-
pellers. The worlds largest airplane, the
giant Douglas Bio bomber, now nearing
fiight-test stage at Santa Monica, Calf,
must employ four of the latest 1000
horsepower engines to give the 5000
horsepower necessary to lift its 80 tons
into the air.
The effects of an 5000 horsepower
engine on single-engined airplane design,
however, are something of which aero
nautical engineers have had little to say
Some of the answers will be obtained
from the Arny's new high-speed wind
tunnel and 1t is probable that by the
time such an engine is ready, the air
planes will be ready to fly it.
This is especially true since engine de-
velopment toward the 5000 horsepower
giant which has been forecast will be by
successive stages, with steadily increas-
ing airplane performances as horse
powers go up.
First Airplane Engine.
As engine sizes have increased, theil
efficiency also has been improved. The
first airplane engine, built by the Wright
brothers for their 1903 flights at Kitty
Hawk, developed IL horsepower with
"dry" weight of IA pounds, exclusive o.
cooling apparatus and fluid. At weigh
of IL pounds per horsepower, the Wrigh
engine was far more efficient than an!
then available. Today, designers haV'
reduced airplane engine weight pc
horsepower to 108 pounds and expec
In the near future to reduce the weigh
to less than one pound per horsepower
At the same time, the durability OF en-
pines has been increased very greatly
During the World War the best engine
had to be overhauled every so hours
Today they are overhauled every 81
hours in this country and American
built engines in the European war ar
running as long as 1000 and 1900 hour
between complete overhauls. In an air
plane flying 200 miles per hour, whicl
is slow for modern warplanes, this woul
mean 100000 to 10000 miles OF trave
between overhauls. Many OF the Euro
pean engines, on the other hand, requir
overhauling at 120 to $50 hours. Tn
superior machining of American aircrai
engines, to which the longer life betwee
overhauls is due, came as revelation {
French and British users.
Increasing the size of a successful en-
CINE and its horsepower output is some
thing more than a matter of scaling u
the size of its parts. Many drastl
changes in design and even in metallurg
are required One of the most pressin
problems, for example, has to do wit
the design of bearings. The crankpi
bearing in the modern 200o-horsepowt
air-cooled engine, for example, takes
load of nearly As tons. Coupled wit
high engine speeds, this presents lubr
cation problem never before encounters
in a power plant of any kind.
None of the finest lubricants availab
was good enough. Hydrocarbon oils we
disintegrated under the tremendous pre-