Evening star., 1933-03-19

Army Air Corps during the past year
has made considerable progress in at
tanning the goal set in the four "di-
receives" covering pursuit aviation.
Pursuit aviation is divided by these
directives into four subtypes Of air.
planes, each designed for a specialized
type OF combat duty. The types are
designated as high speed at low alti-
tude, high speed at high altitude, BIZ
| plane, or two-seater, and intermediate
maneuverable
Though the types are separated for
the purposes of the directives, in prac-
tice it has been difficult to obtain a
| clear demarkation, owing to the fact
that In the present models compara-
lively modest changes will convert an
airplane from one type to another or
make it available within the fields cov-
cred by two or more directives.
AS progress Is made in airplane de-
sign and construction, however, the line
OF demarkation becomes ever clearer
and inevitably the time must come
when highly specialized types of pur-
suit airplanes will prevail in the COM
bat squadrons.
In the first of the four directives the
Air Corps has obtained some results,
though still short of its goal. The KIP
934, which, il it goes into service, will
become the P-31, was built by Curtiss
for high speeds at low attitudes and
has undergone extensive flight testing
at Wright Field. Dayton, Ohio
Though tested with both the geared
Conqueror liquid-cooled engine and the
Wasp, air-cooled, the XP-934 still is
short Of the goal 1t was hoped to at
tain and further work IS in progress to
| further increase its already high maxi
mum speed.
Various Designs Submitted.
There have been various preliminary
designs submitted by airplane manu-
facturers to meet the requirement of
high speed at low altitude, according
to report made by Maj. C. w. How
| ard. Air Corps, chief of the engineering
section, who has charge of this work
for the Army. Most of these designs
are based on the racing planes used in
the National Air Races.
In general, however" Maj. Howard
said. "the division (Materiel Division,
Army Air Corps, Of which the engineer
ing section is a branch) will not en-
courage manufacturers to lay down new
types until high-powered engines now
| IN experimental stages have been
proved to meet military requirements.
Preliminary designs and calculated per-
formance on a considerable number of
combinations Of airplanes and engines
are under way. These preliminary de-
signs and performance estimates con-
tain studies of adaptation of present
models, with the various engines, and
new designs and lay-outs. some of
which will be used in connection with
the preparation of new directives, and
others as basis of making changes in
existing types"
In the high speed at high altitude
classification, the Air Corps has made
notable progress. Geared propellers
and more efficient superchargers for de-
liver1ng air at sea level pressures to the
carburetor have resulted in vastly i'm
proved performance at high altitude. A
P-6D pursuit plane Of 1925 model, at
10000 feet, has been made to give q
high speed in excess Of 200 miles per
charger was used in connection with q
V-1570 liquid-cooled engine.
The Air Corps, however. has gone be-
yond the comparatively old P-6D type
and now has under test a new XP-23
Curtiss, powered with a Conqueror en-
gine, geared and supercharged for great
speed at high attitudes. AS with all
new type planes, exact performance
figures are not disclosed, in accordance
with military policy in force in all fore
most world air powers.
New Two-Seater Tested.
In the two-seater classification, the
Air Corps has one squadron, the Gath
Pursuit Squadron, of the 1st Pursuit
Group, Selfridge Field, Mich, equipped
with the P-16 Berliner-Joyce two-seater
biplane. This squadron has carried on
field work with the P-16 for nearly a
year and invaluable lessons have been
learned, as q result Of which even fur
ther progress is in sight. The Air
Corps now IS carrying on work on the
P-25. built by Consolidated, a two
scatter low-wing monoplane. Although
misfortune has attended the flight test
ing Of this type at Wright Field, def
| mite progress has been made. This
plane, Maj. Howard said, shows great
promise"
In the intermediate maneuverable
classification the Air Corps is directing
its efforts at present chiefly to the P-26
Boeing, low-wing monoplane, a fast,
highly maneuverable single-seater The
P-26 met the directive requirements in