Sadly, the Douglas TBD Devastator torpedo bomber will
forever be remembered for its tragic involvement during the Battle of Midway
and the sacrifice of its crews. Although the aircraft was immediately removed
from front-line operations, it should not be forgotten that just five years
earlier it was deemed to be the most advanced aircraft of its kind anywhere in
the World. As such, it was the US Navy’s first all-metal mount and the first to
feature hydraulically-assisted folding wings (for improved carrier storage). It
also had the distinction of being first US Navy monoplane to be fielded in
quantity on its carriers.
The Douglas TBD Devastator was born out of a US Navy
requirement issued in 1934 for a carrier-based torpedo bomber. The Douglas
entry was one of the winners of the competition, which also saw orders placed
for the Northrop BT-1 (which would evolve into the SBD Dauntless), the Brewster
SBA and the Vought SB2U Vindicator.
The Devastator emerged in prototype form as the XTBD-1 to
which first flight was recorded on 15 April 1935. Only a single prototype would
ever be constructed and evaluated, this being powered by a single Pratt &
Whitney XR-1830-60 radial piston engine. The XTBD-1 was accepted into service with
the US Navy as the TBD-1 and these entered production with a Pratt &
Whitney R-1830-64 series Twin Wasp radial piston engine of 850hp.
The Devastator marked a large number of `firsts’ for the US
Navy. It was the first widely used carrier-based monoplane as well as the first
all-metal naval aircraft, the first with a totally enclosed cockpit, the first
with power-actuated (hydraulically) folding wings and in these respects the TBD
was revolutionary. A semi-retractable landing gear was fitted, with the wheels
designed to protrude 10in (250mm) below the wings to permit a `wheelsup’
landing which might limit damage to the aircraft. A crew of three was normally
carried beneath a large `greenhouse’ canopy almost half the length of the
aircraft. The pilot sat in front; a rear gunner/radio operator took the
rearmost position, while the bombardier occupied the middle seat. During a
bombing run, the bombardier lay prone, sliding into position under the pilot to
sight through a window in the bottom of the fuselage, using the Norden
Bombsight. Maximum speed was listed at 206mph with a range of 435 miles and a
service ceiling of 19,700ft.
In terms of defensive armament, the TBD Devastator was
limited. The pilot controlled a single forward-firing 7.62mm general purpose
machine gun or 12.7mm heavy machine gun to engage targets ahead of his
position, suitable for strafing actions during the bombing run. The rear gunner
operated a single 7.62mm machine gun, though this was later upgraded to include
a pair of 7.62mm machine guns for slightly improved defence. However, it was in
its offensive prowess that a torpedo bomber would ultimately succeed or fail.
As such, primary armament for the TBD Devastator family was a single 1,200lb
Mark 13 torpedo for attacking ships along their broadsides.
A total of 129 of the type were purchased by the US Navy’s
Bureau of Aeronautics (BuAer), and starting from 1937 began to equip the
carriers USS Saratoga, Enterprise, Lexington, Wasp, Hornet, Yorktown and
Ranger. In pre-war use, TBD units were engaged in training and other
operational activities, but the US Navy was already aware that the TBD had
become outclassed by fighters and bombers of other nations. Although a
replacement was in the works, when the US entered World War 2 the Devastator
was still in front-line service with over 100 operational.
With the Japanese attack on Pearl Harbor, the Devastator
began to see combat action. Taking part in attacks on Japanese shipping in the
Gilbert Islands in February 1942, TBDs from USS Enterprise had little success.
This was largely due to problems associated with the Mark 13 torpedo. A
delicate weapon, the Mark 13 required the pilot to drop it from no higher than
120ft and no faster than 150mph making the aircraft extremely vulnerable during
its attack. Once dropped, the Mark 13 had issues with running too deep or
simply failing to explode on impact. For torpedo attacks, the bombardier was
typically left on the carrier and the Devastator flew with a crew of two.
Additional raids that spring saw TBDs attack Wake and Marcus Islands, as well
as targets off New Guinea with mixed results. The highlight of the Devastator’s
career came during the Battle of the Coral Sea when the type aided in sinking
the light carrier Shoho. Subsequent attacks against the larger Japanese
carriers the next day proved fruitless.
At Midway, a total of 41 Devastators, the majority of the
type still operational, were launched from Hornet, Enterprise and Yorktown to
attack the Japanese fleet. The Devastator proved to be a death trap for its
crews. It lacked manoeuvrability, had light defensive weaponry and poor armour
relative to the weapons of the time. Moreover, its speed on a glide-bombing
approach was a mere 200mph (320km/h), making it easy prey for fighters and
defensive guns alike. Tragically, during the battle, only four TBDs made it
back to Enterprise, none to Hornet and two to Yorktown, without scoring a
torpedo hit. This brought the aircraft’s combat career to an inglorious end.
In the wake of Midway, the US Navy withdrew its remaining
TBDs and squadrons transitioned to the newly arriving Avenger. The 39 TBDs
remaining in the inventory were assigned to training roles and by 1944 the type
was no longer in the US Navy’s inventory.
Reputation I
The reputation of the Douglas TBD Devastator has been
somewhat blackened by circumstance. It was a very early monoplane design with
ludicrously inadequate power. While its performance was still better than that
of the Swordfish, it faced much tougher defenses. Moreover, USN doctrine for
its employment was inadequate, in that it did not sufficiently stress delivery
of a massed, coordinated attack by dive bombers and torpedo bombers. Finally,
it was lumbered with a torpedo which, while fundamentally adequate, was not
very effective in 1942 due to several problems.
The Devastator story is limited by the aircraft’s small
production run, but within the careers of those 130 airframes that were built
is a surprising variety of trivia. For instance, barely half of all TBDs were
assigned to Pacific Fleet squadrons between the climactic events at Pearl
Harbor and Midway. Of those 76, more than threequarters (59) were lost to
combat or operational causes.
For such a well-known aircraft, the TBD logged surprisingly
little combat. In fact, the 178 sorties that resulted in enemy contact equate
to barely one mission for every aircraft produced. On average, each wartime
Devastator assigned to a Pacific Fleet squadron flew 2.2 combat sorties between
1 February and 6 June 1942. The highest individual mission count probably
belonged to VT-5’s BuNo 0354, which logged perhaps six combat sorties,
including a Japanese submarine contact.
Overall, the five PacFleet TBD units launched 132 aircraft
with torpedoes, of which about 95 (72 per cent) dropped their `fish’. However,
only ten hits were recorded – 7.5 per cent of the aircraft launched and 10.5
per cent of Mk 13s dropped. By far the most successful mission was the combined
Lexington-Yorktown strike of 7 May, when full co-ordination with SBDs saw 36.8
per cent hits from 86 per cent of the aircraft launched.
At Midway, VT-3 and -6 each got about 42 per cent of their
TBDs to the drop point despite severe opposition from fighters and
anti-aircraft gunfire. Torpedo Eight, poorly positioned from the start, managed
just one known drop from 15 TBDs. The overall performance figures were further
skewed when VT-6’s three pilots followed orders and jettisoned torpedoes rather
than attack the cruisers Mogami and Mikuma on 6 June.
Although primarily a torpedo aircraft, the TBD flew nearly
one-quarter of its sorties with bombs. A further five sorties resulting in
contact with the enemy were made with depth charges. The 112 torpedo sorties
resulted in four Mk 13s jettisoned or failed to release. Thus, 108 effective
sorties resulted in about 95 torpedoes dropped, with ten hits on four ships, of
which two were sunk.
The Japanese Navy was disappointed with the B2M design so it
turned to its own resources in designing a replacement. The First Naval Air
Technical Arsenal’s engineers, led by Suzuki Tamefumi, designed the
three-seater biplane Type 92 Carrier Attack Bomber (also known as the B3Y1)
that entered service in 1933. Wing structure was of wood and the fuselage
structure of welded steel tube. Powered by a 750-horespower Type 91 water-cooled
engine, the B3Y1 had a top speed of 136 miles per hour and a range of 500
miles. This model’s engine also proved unreliable and the performance,
especially in range, was unsatisfactory, so a new design was prepared by
Kawasaki Sanae at the First Naval Air Technical Arsenal that entered service in
early 1937 as the Type 96 Carrier Attack Bomber (or B4Y1). The new design
married the wings of the successful E7K1 shipboard floatplane to a new fuselage
and tail unit to produce a three-seater biplane with all-metal structure.
Powered by an 840-horsepower Nakajima Hikari radial engine, it had a maximum
speed of 173 miles per hour and a range of 978 miles, both markedly superior to
any of its precursors or any similar machine in service, although this
superiority was cut short by the introduction of Douglas’s monoplane TBD-1
later in 1937.
