The third prototype XA-26B 41-19588, S/No 1006 was the last Invader to be built
at the El Segundo plant.
Plans were for the production version of the Invader to be built
at newly-constructed Douglas plants in Tulsa, Oklahoma and in Long Beach, California. It was planned that the solid-nosed
B would be manufactured side-by-side with the transparent-nosed C at both plants.
The production of the Invader began
first at the Long Beach plant. The solid-nosed B was actually the first off the production line.
The first of five A-26B-1-DL Invaders appeared
in September of 1943. As compared with the prototype, the A-26B had an increased bomb load (6000 pounds) and higher internal
fuel capacity of 1600 US gallons. The powerplants were housed in slightly revised nacelles and drove three-bladed propellers
The engines were a pair of 2000 hp Pratt & Whitney R-2800-27
Fifteen A-26B-5s followed with minor changes and which eliminated the camouflage that had
been applied previously to bombers. These versions had one 75-mm cannon in the nose and two 0.50-inch machine guns on the
A new all-purpose nose was installed beginning with the A-26B-10-DL. Initially, the USAAF
was undecided about what armament this version should carry. As originally planned, it was expected that the A-26B would be
fitted with a variety of alternate solid nose sections, and that one deemed to be the best would be selected. Options that
were tested on early A-26Bs included
One 75-mm cannon to starboard and two 0.50-inch machine guns
One 75-mm cannon to starboard and one 37-mm cannon to port
Two 37-mm cannon with one on each side of the nose;
One 37-mm cannon to starboard and two 0.50-inch machine guns
Four 0.50-inch guns starboard and one 37-mm cannon to port
Four 0.50-inch guns to starboard and two 0.50-in guns to port.
Eventually at the end of 1944, the USAAF finally made up its mind
and decided that the solid-nosed A-26B would have six machine guns with 400 rounds per gun. The guns in the two turrets had
500 rounds each.
Beginning with the A-26B-15, the forward-firing armament could be supplemented by
eight 0.50-inch guns mounted in four twin packages underneath the outer wing panels.
Five aircraft from the initial
Fiscal Year 1941 A-26 production batch were completed as A-26C-DL bombers with transparent noses and two nose guns.
These were destined to be the only A-26Cs to be built at Long Beach, all the remaining A-26Cs being built at Tulsa.
first 500 Invaders (up to A-26B-40-DL) were built at Long Beach. A parallel production line was established
at Tulsa, Oklahoma for 500 aircraft ordered on March 17, 1943. The first Tulsa-built A-26Bs appeared in January of 1944. Of
the Tulsa-built Invaders, 205 were delivered as A-26Bs with the rest being built as A-26Cs with glazed noses. Most of these
Tulsa-built A-26Bs were powered by the Ford-built R-2800-71 engine with a revised ignition system.
Although both the
Long Beach and Tulsa plants had started building both Invader versions, it was decided in late 1944 that this was an inefficient
arrangement and that it would make better sense for the Long Beach plant to build only A-26Bs and the Tulsa plant to build
only A-26Cs. This was indeed done, and the Long Beach plant stopped producing A-26Cs after only five were built.
production, a number of improvements were introduced on the line. The oil cooler inlets on the wing leading edge were redesigned.
The dorsal turret was modified to eliminate empennage buffeting. Initial combat reports from the field had complained about
poor visibility from the cockpit, especially to the side. In order to improve visibility, the original flat-topped cockpit
canopy which opened upward on the right side of the cockpit was replaced by a raised canopy opening in clamshell-fashion in
two frameless elements around hinges on both sides of the pilot's cockpit. The new canopy enabled the pilot to see over both
engine nacelles and towards the tail surfaces as well as to check whether both main landing wheels were down. This new canopy
was at first hand-built and fitted to a few early aircraft, but was introduced as standard equipment beginning with the A-26B-30-DL
Beginning with the A-26B-45-DL block, the engines were switched to Ford-built R-2800-79 with
water injection, raising the war emergency power to 2350 hp.
The forward-firing armament of the early A-26B was found
to be insufficient, especially in the Pacific theatre.
Beginning with the A-26B-50-DL production block,
a new eight-gun nose was fitted, and six internally-mounted 0.50-inch guns were mounted in the outer wing panels so that bombs
or rockets could be carried underneath the wings. However, the eight-gun nose and the internal wing guns were often retrofitted
to earlier A-26B versions, so the mere presence of these features cannot be used as a positive identification feature.
aircraft destined for service in the Pacific (-51-DL, -56-DL, -61-DL, and
-66-DL), the remotely-controlled ventral turret was replaced by a 125-US gallon auxiliary tank for extra
A total of 1150 A-26Bs were built at Long Beach (A-26B-1-DL to A-26B-66-DL) and an additional 205 were built
at Tulsa (A-26B-5-DT to A-26B-25-DT).
Production of the A-26B ended at Long Beach in September 1945,
when the end of the war resulted in the cancellation of further contracts. Production of the B at Tulsa had ceased at the
end of 1944 at Tulsa, when the decision was made that the Oklahoma plant would concentrate solely on the transparent-nosed
In June of 1948, the A-26B was redesignated B-26B. There was no danger of confusion
with the Martin B-26 Marauder, since that aircraft was by that time out of service.
In May 1966, the B-26K was re-designated A-26A for political
reasons ( Thailand did not allow the U.S. to have bombers stationed in country, so the Invaders were redesignated with an
"A", for attack aircraft ) and deployed in Thailand to help disrupt supplies moving along the Ho Chi Minh trail.
Douglas Aircraft Co. El Segundo, California ( Prototype
Douglas Aircraft Co. Tulsa, Oklahoma
- Douglas Aircraft Co. Long Beach, California
Beech Aircraft Corporation, Wichita
McClellan AFB - Refurbishement
In 1914, when the Army first began to acquire tractor-engined aircraft,
the official serial number began to be painted in large block figures on both sides of the fuselage or on the rudder.
These numbers were so large that they could be easily seen and
recognized from a considerable distance. At the time of American entry into the First World War, the large numbers were retained
on the fuselage and sometimes added to the top of the white rudder stripe.
By early 1918, the letters "S.C." (for "Signal Corps") were often
added as a prefix to the displayed serial number. When the Army Air Service was created in May of 1918, the letters SC were
replaced by "A.S". (for "Air Service"). In July of 1926, the Army Air Service was renamed the Army Air Corps, and the serial
number prefix became A.C. for "Air Corps". However, these prefix letters were not part of the official serial number, and
were finally dropped in 1932.
By late 1924, the fuselage serial numbers began to get smaller
in size, until they standardized on four-inch figures on each side of the fuselage. In 1926, the words "U.S. Army" were often
added to the fuselage number, and in 1928 the manufacturer's name and the Army designation were also added to the display,
but this was not always done.
The lack of a readily-visible serial number on Army aircraft began
to be a serious problem, and on October 28, 1941, shortly after the USAAF had been formed, an order was given that numbers
of no less that 4 digits would be painted on the tail fin of all Army aircraft (where feasible) in a size large enough to
be seen from at least 150 yards away.
This was officially called the radio call number, but was almost
universally known as the tail number. Since military aircraft were at that time not expected to last more than ten years,
the first digit of the fiscal year number was omitted in the tail number as was the AC prefix and the hyphen.
Thus Serial #: 44-34713 would interprit as 44, being (1944)
34713 ( The given serial No. )
The number on the fin being 34713
An example regarding Serial No's comes in the form of the below
shot, that was sent to me by Scott Lindley (Spirit of "SC" Fixer and historian)
EB-26C-DT, B-26C-DT modified for missile guidance
tests, USAAF Serial # 44-35300
Regarding the "0" on the fin of this aircraft, for a period in the 50's & 60's there
was a problem with airframes starting to last longer than normal and the possibility of 2 aircraft serialled 48-4500 and 58-3500
both shown as 83500
It was decided that the one that was older would have a ZERO in front of it to denote 'Over
10 years old' so one would have 84500 the other 0-84500
Somewhere along the line somone decided that the ZERO
was an 'O' for Obsolescent and this error has been repeated in many sources.
Understanding Production codes (
Excerpts taken from Randy Wilson's aviation history site )
The manufacturer’s code told not only what company built
the aircraft, but in which plant it was assembled, this was to help deal with minor differences and changes within the system,
especially when trying to join spare parts to the correct airplane.
Following the aircraft type code (A) A-26, came a number, indicating how many of that type had been designed
or ordered by the USAAC. Thus, the A-26 was the 26th attack aircraft designated or actually ordered. Some numbers were
assigned to designs which were never built, and the sequence of numbers does not always indicate which came first.
Finally, many U.S. Army aircraft had a popular name, such as Invader. These names were often dreamed up by the
Thus you have the A-26 Invader
Production codes, what did they mean
Designation Prefix Aircraft Mod Var
Block Loc Pop
B 15 DL
V - Prefix for Staff transport (
See Note 3 )
A/B - Aircraft type or Class
- Attack/Bomber and light weight
26 - The Douglas model No. was sequential with each type, i.e. A-26 as it was the 26th attack aircraft to be orderd
by the USAAC. Each new designation was given, even if the aircraft
was never produced.
B - Series or variant letter
- Usually, the first pre-production batch of a design did not have a series suffix letter, i.e. A-26 and the first full
production version bore the series letter B (solid nose), C (glass nose), although there are a number of exceptions.
15 - Block No ( See
Note 1 )
DL - Manufacturer, in this case
Douglas Aircraft Co., Inc., Long Beach, California ( See Note 2 )
Invader/Counter Invader - Popular name
Note: The B-26K Counter Invader was so named because of
their use as counter insurgency aircraft
and was also often refered to as Little hummer or Little racer
Note 1 : Block numbers
are not part of the official MDS designation, and their use is optional to the various DOD services. In fact, block numbers were
used for some production aircraft (e.g. the A-26) but not all. Block numbers were introduced by the U.S. Army Air Force in
World War II to distinguish between minor sub-variants of a specific aircraft variant, and were originally assigned in steps
of five (1, 5, 10, 15, ...), with the gaps being intended to be used for modifications after production.
The manufacturer’s code told not only what company built
the aircraft, but in which plant it was assembled. Again, this was to help deal with minor differences and changes within
the system, especially when trying to join spare parts to the correct airplane.
2: Douglas plant production codes
- Douglas Aircraft Co. Chicago, IIIinois
Douglas Aircraft Co. El Segundo, California ( Prototype
Douglas Aircraft Co. Oklahoma City, Oklahoma
- Douglas Aircraft Co. Long Beach, California ( A-26 )
- Douglas Aircraft Co. Santa Monica, California
Douglas Aircraft Co. Tulsa, Oklahoma ( A-26
Note 3: In the case
of the JD-1 - J was for Transport/Utility and D was for drone director and mods were carried out at Navy facilities.
Understanding "Buzz" numbers
At the end of World War II there was an abundance of well trained
and confident pilots who frequently flew low over air-bases or residential areas.
In order to prevent this and possible accidents the 8th Air Force
in Germany introduced a letter / number code system for quick identification of low flying aircraft on November 6th, 1945,
termed after what they were designed to stop "buzzing" of airfields etc.
The first letter denoted the
type - A (Attack), B (Bomber), generally the same as the Type Letter in the designation
The second letter has no meaning except for just being the letter
assigned to that aircraft variant. The numbers were simply the last three digits
of the serial number. For example Attack/Bomber
type B-26C S/n: 44-35326 was assigned buzz number BC-326 with C
being the letter assigned to the A/B-26 model. ( See below photo )
Buzz Numbers were dropped in the
mid 1960's when camouflaged aircraft began to appear with low-visible serial numbers. The last use of Buzz Numbers was in
Note: AC was also assigned to A/B-26 Invader