Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-10-07

Two striking demonstrations Of Uncle
Sans latest developments in the sci
ence of military aviation have beer
offered to the public during the past
week; the first at the remarkable ord
nance demonstration at Aberdeen Prov
ing Grounds, Md, last Thursday and
the second at the military exposition
and carnival at the War College here
ending last night.
The Aberdeen demonstrations were
actual service tests designed to show
the f1repower. Of The modern pursuit
plane and bombardment group and the
in the perfection of anti-aircraft ma
terial. The Army Air Corps exhibit at
| the local carnival, on the other hand
was partially a museum exhibit tracing
| the history of aviation development
and partially a demonstration of air
maneuvers and combat flying by planes
of various types.
Guns Trained Mechanically.
The anti-aircraft demonstration at
Aberdeen was a revelation to thousands
of scientists and engineers who at
tended and who saw for the first time
the wonderful new f1re-control appa-
ratuS which automatically trains bat
terry of guns on their aerial target,
keeping the guns pointed during the
entire time the target is within range.
The control apparatus mechanically
computes the height of the target above
the ground, its distance from the guns,
its speed the velocity of the wind and
other data entering into fire control,
keeping the weapons ION the target"
with an accuracy that is little ap-
palling. The value of such an appa-
ratuS in anti-aircraft defense may be
appreciated when it is realized that
there are seven "variables' entering
into the Spotting Of an aerial target
and that formerly seven highly trained
men were required to perform the single
duty of swinging the gun muzzleS.
The mechanical pointer, which has
service, was used by the SD Coast Ar
tillery Regiment, Anti-Aircraft. from
Fort Totten, N. Y, with 3-inch guns
and 80 and so nm. Browning machine
guns. A sleeve target, with 5-foot
opening and q feet long, towed 1900
feet behind an airplane, was used and
q number of direct hits scored on
straightaway flights at fixed attitudes.
The 3-inch anti-aircraft gun is the
latest type for mobile defense against
aircraft, firing shell or shrapnel at a
muzzle velocity of $500 feet and $500
feet, respectively, per second. The pro-
jectiles weigh Is pounds and attain a
vertical range of 10000 yards and a
horizontal range of $4,000 yards. The
rate of fire is about % shots per minute.
The two caliber machine guns are fired
either from tripods or four-gun multi
pie mount, the .30-caliber at rate OF
FIRE of $50 shots per minute and the
.50-caliber about 500 shots per minute.
Huge Bombs Exploded.
The use of 600-pound demolition
bombs, with and without delayed fuse,
was demonstrated A bomb Of each
type was dropped from a Martin
bomber, one with instantaneous contact
fuse and the other with 1.2-Second
delay fuse, used chiefly to obtain a
mining effect against the bottom OF
ships.
At the Aberdeen aviation field there
was an exhibition Of bomb types used
by foreign governments during the
World War, as contrasted with Ameri-
can bombs Of recent development, In
GLIDING augmentation, chemical and
demolition types. There also was an
exhibit of the various types of pursuit,
bombing and observation planes used
by the Army Air Corps.
The combat pilots came into their
own at Aberdeen with demonstration
of fighting methods employed by. pur-.