Certainly one of the most elegant bomber aircraft to appear in the
early years of World War II, Martin's B-26 Marauder stemmed from a US
Army Air Corps high-speed medium bomber specification which had been
circulated to US manufacturers in January 1939. This called for a
number of characteristics which, together, made the US Army requirement
very difficult to meet. To accommodate a crew of five, which meant that
it must be fairly large, it was required also to be fast and with good
high-altitude performance, to have a range in excess of 2,000 miles
(3219 km), and be able to carry good defensive armament plus a
worthwhile load of bombs.
Martin's design, by Peyton M. Magruder, was far in advance of competing
submissions, and as the company not only guaranteed that performance
would be as good as, or better than performance estimates and also
promised early production, it was not surprising that this company was
chosen to build the USAAC's new bomber. The startling feature of the
contract, awarded in September 1939, lay in the fact that it was for a
substantial number of production aircraft (201) ordered 'straight off
the drawing board', a course then unprecedented in USAAG history. No
prototypes or preproduction aircraft were called for, so the first of
the Martin Model 179s, designated B-26 by the US Army, flew for the
first time on 25 November 1940.
As
then flown it was a cantilever shoulder-wing monoplane of all-metal
construction, except that all control surfaces were fabric-covered, and
the conventional but small-area wing had plain trailing-edge flaps. The
fuselage was a near perfect aerodynamic cigar-shape form of circular
cross-section, marred only by the 'step' of the windscreen, and with a
conventional tail unit which had a high-set tailplane. Landing gear was
of the retractable tricycle type, the main units retracting forward and
upward into the centre of the engine nacelles, and the nosewheel unit
aft into the forward fuselage. To provide the necessary performance a
new Pratt & Whitney engine had been selected, the 1,850 hp (1380 kW)
R-2800-5 Double Wasp, and the two of these each drove a four-blade
constant-speed fully-feathering propeller. An innovation was the use of
a 'cuff' at the root end of each propeller blade, this enabling the
normally useless area of each blade to provide extra airflow for
improved engine cooling. Initial armament comprised two 0.30 in (7.62
mm) machine-guns, one in the nose position and one in the tailcone,
plus two 0.50 in (12.7 mm) guns in an electrically operated dorsal
turret, the first powered gun turret to be installed in an American
bomber. Maximum bomb load, all carried internally, was as much as 5,800
lbs (2631 kg) for deployment at short range.
(ABOVE)
Just away from its Italian base, a Martin B-26F-MA cruises atop a
cloud deck. Crewed by Sgt. Joe Allen, the Marauder was one of three in
the 441st Squadron, 320th Bomb Group, bearing the number 07. While
combat operations caused the first two 07s to crash land, the crews
got back unharmed. The bomber's structure, though built for survival,
nearly always ensured Class 26 (salvage) status after a wheels up
landing. Allen was quite proud he never lost a combat crewman.
Basically similar to the B-26B, the F model's major change was a 3.5
degree increase in wing incidence angle, a shot at giving the aircraft
improved takeoff performance. The Marauder went through a number of
design changes throughout its service life, but this visible
difference in the raised thrust line of its Pratt & Whitney R-2800
engines is one of the easiest to spot, a characteristic of all
subsequent models
Following the first flight, it was not until February 1941 that
succeeding production aircraft began to come off the line, and while
some of these were diverted for test purposes, there were sufficient
available to begin deliveries to the USAAC. This initial equipping of
the US Army Air Corps' squadrons was not without problems, for while
they had been supplied with an aircraft which attained the desired high
performance specification, this performance had been achieved at the
expense of good low speed handling characteristics, leading to what is
usually termed a 'hot' aeroplane. This made conversion training a
difficult and slow process, for even at loaded weights well under
maximum the aircraft's stalling speed was not far below 100 mph (161
km/h), a very high figure for that period.
In
spite of this Marauders, as the B-26 had been named in preference to
the originally chosen Martian, gradually began to equip USAAF squadrons
and as experience was gained a number of modifications were considered
to be desirable, resulting in the B-26A of which 139 were built. All
had engines of the same power as the B-26, but R-2800-5, -9 and -39
units were installed in different batches. The electrical system was
changed from 12-volt to 24-volt, two additional fuel tanks were
installed in the bomb bay, provision was made for the carriage of a 22
in (559 mm) torpedo and, as a result of combat reports from the war
then being fought in Europe, the nose and tail guns of 0.30 in (7.62
mm) calibre were replaced by similar 0.50 in (12.7 mm) installations.
The result of these changes, of course, was to increase the gross
weight and also, as a consequence, the problems that were soon to come
to a head.
Before that, however, the Japanese on 7 December 1941 attacked Pearl
Harbour and, on the following day, the USAAF's 22nd Bombardment Group
was despatched to the Pacific zone, becoming operational initially from
northern Australia in April 1942. This unit's B-26As soon found ready
employment in a variety of roles, including unsuccessful torpedo
attacks against the Japanese fleet engaged in the Battle of Midway. At
about that same time the RAF received three examples of the B-26A for
evaluation, these being designated Marauder 1. Successful testing
resulted in this type being chosen for tactical use in the North
African campaigns, and the additional 48 of this version allocated
under Lend-Lease were delivered direct to the Middle East and used
first to equip No. 14 Squadron.
While these events had been taking place, a special board of
investigation had been set up in the USA, under the chairmanship of
Major General Carl Spaatz, to enquire into the abnormally high accident
rate associated with the B-26, especially during training, and to
decide whether production should be terminated. Fortunately this latter
course was not adopted for, with growing experience of how best to
handle the Marauder, it was later to have the lowest attrition rate of
any American aircraft operated by the US 9th Air Force in Europe. The
eventual findings of the investigation board resulted in continuing
production, but with some recommendations regarding modifications
intended to improve low-speed handling.
During the foregoing enquiry all production had been suspended but soon
after it was resumed, in May 1942, Martin began to deliver its first
B-26Bs, the major production version of which 1,883 were built. These
incorporated initially improvements which combat experience had proved
to be necessary, but many other changes were introduced on the line
throughout the long manufacturing run. Major items included the
installation of 1,920 hp (1432 kW) R-2800-41 or R-2800-43 engines, the
introduction of slotted trailing-edge flaps, and a lengthened nosewheel
strut to increase wing incidence and so improve take-off
characteristics. The most important change, one which had been
recommended by the enquiry board, was an increase in wing span/area but
this, in fact, achieved nothing because the USAAF immediately upped the
gross weight. The comparisons of maximum wing loading are interesting,
the B-26's being 53.16 Ibs/sq ft (259.5 kg/m2), the early B-26B's 56.48
lbs/sq ft (275.7 kg/m2), and the late B-26B's 58.05 lbs/sq ft (283.4
kg/m2), which all goes to prove that the initial handling problems were
largely those of inexperience. Today little is thought of a wing
loading of 149 lb/sq ft (728 kg/m2), and that for a civil transport
aircraft, not a 'hot' military aeroplane.
The
introduction of the larger wing necessitated an increase in vertical
tail surface area, achieved by increasing fin and rudder height by 1 ft
8 in (0.51 m). The armament, through a succession of modifications,
became almost as potent as that of the USAAF's heavy bombers, with no
fewer than 12 0.50 in (12.7 mm) machine-guns. The increasing demand for
Marauders resulted in the establishment of a second production line by
Martin at Omaha, Nebraska, which built 1,235 aircraft as B-26Cs from
late 1942, these duplicating various batches of the B-26Bs built at
Baltimore, Maryland. The D and E designations were taken up by two
one-off aircraft: the XB-26D was an experiment in thermal wing
de-icing; and the XB-26E was a 'weight watchers' version with some
2,000 lbs (907 kg) weight reduction and with the dorsal turret moved
forward to a position adjacent to the wing leading edge.
The
final production versions were the generally similar B-26F (300 built)
and B-26G (893), plus 57 TB- 26Gs without armament and other purely
operational equipment to serve as target tugs or trainers. The major
difference between these aircraft and the B-26B/B-26Cs which had
preceded them lay in a final attempt to improve take-off performance,
wing incidence being increased by 3°30', so giving a noticeable
nose-in-the-air look to the engines. There were also some armament and
fuel system changes. Last of the B-26 designations was taken by a
single XB-26H with tandem bicycle type landing gear with each of the
main units carrying twin wheels and an outrigger, for balancing, was
housed in each engine nacelle. This experimental installation was made
to evaluate a landing gear of this type which was being developed for
the Boeing XB-47.
All
of the USAAF's early deployment of the B-26 had been confined to the
Pacific theatre, but B-26Bs and B-26Cs began to appear in North Africa
during November 1942, equipping 12 squadrons of the 17th, 319th and
320th Bomb1l.rdment Groups of the 12th Air Force, providing admirable
support to the Allied ground forces as they followed the bitter but
victorious trail to the south of France via Sicily, Italy, Sardinia and
Corsica. However, the B-26's first operation with the 8th Air Force in
Europe was disastrous, all 11 aircraft sent to make a low-level attack
on installations in the Netherlands failing to return to base.
Subsequently, in a tactical role, Marauders went from strength to
strength in operations with the USAAF's 9th Air Force, also in Europe.
Under Lend-Lease the RAF received a total of 522 Marauders, these
comprising the Marauder I mentioned above, plus Marauder IA (B-26B), II
(B-26C) and III (B-26F/B-26G). Used by the RAF's Nos. 14, 39, 326, 327
and 454 Squadrons and the South African Air Force's Nos. 12, 21, 24, 25
and 30 Squadrons, they were deployed most successfully alongside the
B-26s of the US 12th Air Force, after initial failure in a torpedo
carrying role.
In
1943 the USAAF converted 208 B-26Bs and 350 B-26Cs for use as
high-speed target tugs, stripping out all armament and operational
equipment, and these were redesignated initially as AT-23A and AT-23B
respectively, but subsequently TB-26B and TB-26C. Of these the US Navy
acquired 225 AT-23Bs which they designated JM-1, and 47 TB-26Gs, the
last Martin production version, as JM-2s.
Nicknames:
Widow-Maker; The Flying Coffin; B-Dash-Crash; The Flying
Prostitute; The Baltimore Whore (The last two because it had no
visible means of support; "Baltimore" because the Martin Company was
located there.)
Specifications (B-26G):
Engines: Two 2,000-hp Pratt &
Whitney R-2800-43 Double Wasp radial piston engines.
Weight: Empty 25,300 lbs.,
Max Takeoff 38,200 lbs.
Wing Span: 71ft. 0in.
Length: 56ft. 1in.
Height: 20ft. 4in.
Performance:
Maximum Speed: 283mph
Ceiling: 19,800 ft.
Range: 1,100 miles
Armament:
11 12.7-mm (0.5-inch) machine guns
Up to 4,000 pounds of bombs
Number Built:
5,157
Number Still Airworthy:
One, with at least one more undergoing restoration to flying condition.
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