Strana 9
HISTORY
to Curtiss on April 26, 1939, for 524 P-40s at
a cost of nearly 13 million USD. Again, foreign
customers came calling at Curtiss. France was
first to order the export version of the P-40,
tagged the Tomahawk by Curtiss, and Great
Britain soon followed suit.
Curtiss built 525 Hawk 81s in three versions
of the P-40 for the U.S. Army. Only a few of
these saw combat in Hawaii, the Philippines
and Iceland early in the war. More than twice
as many export Hawk 81 Tomahawks were
built. These 1,181 aircraft fought extensively
with the British Commonwealth air forces in
North Africa, the American Volunteer Group
of Chinese Air Force in Burma and China; and
with the Red Air Force on the Eastern Front.
There was no denying that the Hawk
81 was a commercial success for Curtiss,
but a challenge was looming for the company’s
design staff. Thus far, Curtiss had been unable
to wring sufficient performance from the Hawk
81 to match the best European designs, and
one of the main problems was that the plane
was underpowered. The output of the 1,090 HP
Allison V-1710-33 engine, with its single-stage
supercharger, was insufficient to propel the
airframe to its maximum capabilities for speed
and service ceiling. The U.S. would soon need
fighters with more power than the current
C-series V-1710 could deliver, so Allison
designers went to work on the problem.
Unfortunately, the fix wasn’t so simple as
merely souping up the engine. The C-series
V-1710 delivered power to the propeller via an
internal spur reduction gearbox, but this de
vice was only able to handle 1,100 horsepower,
and the engine already was pushing this limit.
The new Allison, and all F-series Allisons
to follow, featured an external propeller
reduction gearbox drive, which was beefed up
sufficiently to absorb the 1,150 horsepower of
the V-1710-39 (F3R) and more. The reduction
ratio remained 2:1, but the new engine was
10.16 inches shorter than previous versions,
and the thrust line was raised several inches
so the gearbox could mount between the
cylinder banks at the front of the engine.
The redesign of the V-1710 had major
implications for Curtiss, because the new
engine, with its shorter overall length and
raised thrust line, did not conform to the
nose contours of the Hawk 81. It not being
practical to craft a new nose for the Hawk
81, Curtiss designers took this opportunity to
draw up an entirely new fuselage. The change
was considered sufficient to cause Curtiss to
give the plane a new designation, the Hawk
87. The U.S. Army continued to call it a P-40,
designating it the model D, while the Royal Air
Force gave it a new name, the Kittyhawk.
On the way to better Hawks
The Hawk 87 incorporated a number of
improvements over the Hawk 81. The fuselage
was not only 6 inches shorter but also slightly
shallower, top to bottom. Up front, the nose
guns were eliminated, and a deeper cowling
with a larger opening held the coolant and
oil radiators under the engine. Because the
propeller hub sat higher on the nose, landing
gear legs could be shorter and still allow
clearance for the propeller during takeoffs
and landings.
To improve visibility for the pilot, the cockpit
opening was deeper with a larger sliding
canopy and an enlarged windshield with flat,
bulletproof glass in the center panel. The rear-
view coves behind the cockpit also were bigger.
In addition, the airframe was stressed to carry
one 500-pound bomb or a drop tank of 52 or
75 gallons under the belly.
The wing and tail designs were relatively
unchanged from the Hawk 81. The new plane’s
guns were mounted in large bays in the wings
and aimed so their fire would pass outside the
arc of propeller, converging about 300 yards
in front of the plane.
The Hawk 87 line was a superior warplane
to the Hawk 81, but not by much. While the
changes in armament made it more versatile,
the new model’s performance remained
unimpressive. As a result of all the changes,
the combat gross weight of the Hawk P-40D
rose to 8,809 pounds. At the same time, the new
V-1710-39 engine produced just 60 horsepower
more than its predecessor. Despite having
a slightly sleeker profile than the P-40C,
the P-40D boasted a top speed just 5 miles
The 57th Pursuit Group, USAAC, flew P-40Es in the U.S. prior to deploying to North Africa in the summer of 1942.
Capt. Phil Cochran, commanding officer of the 65th FS “Fighting Cocks,” flew No. 50 from the airbase at Windsor
Locks, Connecticut, during that period. (photo: author’s collection)
Col. Robert L. Scott was the first Commanding Officer of 23rd FG. He scored 13 aerial victories during the War
making him one of five top scoring USAAF P-40 fighter pilots. A member of the ground personnel is pointing on
the five victory marks on Scott’s second P-40E. (photo: NARA)
INFO Eduard
9
February 2025