Tactical Turnabout: Development of the Last
U.S. Propeller-Driven Attack Aircraft
Martin’s XBTM-1 was the
frontrunner in the race to become the Navy’s newest attack aircraft
until Douglas’s XBT2D-1 entered the picture.
Flemmings Island
Field, Florida, June 12, 1949: Navy
pilot Ens. Rex J. Vannoy of VA-84 was about to learn the value of a
pre-takeoff checklist. The big Martin AM-1 Mauler he was flying had just
left the runway at full takeoff power and he’d smartly moved the gear
selector lever to the "UP" position. Seconds later, at an altitude of
about 75 feet, the plane’s 28-cylinder Pratt & Whitney R-4360 engine
coughed a few times and completely died: In his haste to take off,
the young pilot had neglected to switch fuel tanks. At that moment,
there was no time for him to do anything except land the airplane -
straight ahead, gear up. Without power, the 10-ton Mauler dropped like a
stone. Evidently not forgetting everything he’d learned, Vannoy
maintained flying speed and bellied the plane into the overrun. Still
moving at nearly 100 mph, the big Mauler erupted through the perimeter
fence, slid across a road, snapped down a telephone pole, demolished a
second fence, and didn’t come to a complete stop until it plowed into a
stand of pine trees. Ensign Vannoy survived the incident; his aircraft,
AM-1 Bureau No. 22326, however, was a complete write-off. Ironically, the
most serious threat to "Able Mabel" (the Mauler’s unofficial
nickname) wasn’t inexperienced naval aviators, but an arcane process
known as the naval aircraft procurement system.
The Bomber-Torpedo
Requirement
Aircraft procurement is often dictated by the
lessons learned in combat, and the early carrier battles of WWII taught
naval strategists that a higher ratio of fighter aircraft was needed in
the carrier air groups to ensure air superiority around the task force
itself, and provide better protection for the aircraft of the carriers’
strike force. As a result, a decision was made in early 1943 to downsize
the complement of torpedo and scout-bombers (i.e., SBDs or SB2Cs and TBF/TBMs)
and replace them over time with one type of single-seat, multi-role strike
aircraft under the new designation bomber-torpedo (BT). With extra fighter
protection, strike aircraft would no longer need to carry gunners, and the
weight normally associated with aircrew, guns, and ammunition could be
exchanged for useful load and greater range. Moreover, with the more
powerful engines becoming available (i.e., the Wright R-3350 and the
P&W R-4630), the new BT types were likely to carry twice the payload
of existing torpedo and scout-bombers, thereby reducing the number of
strike aircraft needed by half. And to optimize mission flexibility, the
requirement further specified that all ordnance be carried on external
racks.
During the same timeframe, Douglas Aircraft Co.
was already at an advanced stage of development with an aircraft that had
been designed as an SBD/SB2C replacement - the two-place, tricycle-gear
R-3350 powered XSB2D-1 Destroyer; similarly, the Airplane Division of
Curtiss-Wright had the XSB3C-1 - a larger, more powerful . . .
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Douglas XBT2D-1 Prototype
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