Douglas Aircraft's Invader attack and medium bomber spans three wars
by Randy Wilson
Copyright © 1997 by the Confederate Air Force and Randy Wilson. All rights reserved.
In 1947, the U. S. Army Air Forces (USAAF) were reorganized into the U. S. Air Force (USAF), joining the Army and Navy as an independent armed force. A year after loosing the "A" for Army, the Air Force also lost its "A" designation for attack aircraft, carried by the Douglas A-26 Invader during World War II, and the Invader became the Douglas B-26.
Hold on there, wasn't the B-26 the Martin Marauder? Yes, but in 1948 the last of the Martin B-26s were withdrawn from active service, thus freeing up the designation for the newer Douglas bomber. So, during and after the Korean War, the Invader was the B-26! And if you think this was confusing, after the "A" for attack designation was reinstated by the USAF in 1962, some rebuilt Douglas B-26Ks were redesignated as A-26As and saw action in the Vietnam war.
Clearly the Douglas A-26 was an exceptional design to have served from World War II into the 1970s. However, the Invader's development was beset by a number of problems, both design and political, which slowed its introduction and limited its effective use during WWII.
In March 1936, Ed Heinemann and Jack Northrup of the Douglas Aircraft Co. began the design of a twin-engine attack aircraft under the company designation DB-7. Both the U. S. Army Air Corps (USAAC) and France were interested, and the prototype flew on Oct. 26, 1938. The first of an initial order for 270 French DB-7s was completed in August 1939, and the USAAC ordered 63 as A-20 Havocs. A total of about 7,478 A-20s were built during WWII, with more than 2,900 seeing service with the Soviet Union as part of the Lend-Lease program. The A-20 also saw service with the British, who called it the "Boston".
While the A-20 was seeing combat in Europe, America was still at peace, but the effectiveness of the A-20 led Douglas to design a faster, more heavily armed version, which could also serve as a medium bomber as well as an attack aircraft. New features included a laminar flow wing, advanced double slotted flaps for lower landing speeds, and remote controlled gun turrets, above and below the fuselage, controlled by just one gunner. Power was to be from two Pratt & Whitney R-2800 engines producing 2,000 hp each.
In June 1941 construction of three prototypes began, the XA-26 being a three-man bomber with a clear bombardier's nose, the XA-26A a two-man night fighter and the XA-26B a late addition with a solid nose armed with a 75mm automatic cannon. Even before the first prototype had flown, Douglas was preparing to produce 500 A-26s at its Santa Monica, Calif. plant. However, arguments over the projected price of the planes delayed government approval until late October. In addition, Douglas was building planes for both the Army and Navy at plants in El Segundo and Long Beach, Calif., Tulsa and Oklahoma City, Okla. and Chicago, Ill., and a shuffling of production allocations for different designs between the two services' plants further delayed construction of the A-26.
When it finally flew on July 10, 1942, the XA-26 bomber prototype performed well, with only minor engine cooling problems, and test pilot Ben Howard proclaimed the new design ready for service. But nearly two more years would pass before the A-26 was to see combat with the USAAF.
The XA-26B next flew with a 75mm cannon in its solid "gun" nose, however, the big cannon's slow rate of fire limited its firepower, especially in as fast a plane as the A-26 was proving to be. Studies of a number of combinations of machine guns and cannons further delayed production of the attack version. By this time, the Northrup P-61 Black Widow was already entering production, so the XA-26A night fighter design was dropped.
Officially named the Invader, development of the remote controlled gun turrets and delays in deliveries of some major components from sub-contractors caused further delays in production of the A-26B armed with six 0.50 caliber machine guns in a solid nose and the A-26C bomber with a clear nose. Production finally began in the fall of 1943, the A-26B being produced at Douglas' Long Beach plant, while the Tulsa facility built most of the A-26Cs plus some gun nose B models. Engines in both were P&W R-2800-27 or -71 (the later built by Ford) rated at 2,000 hp.
In the initial production models, up to 3,000 lbs of bombs could be carried in the bombay, with another 2,000 lbs mounted in underwing racks. In addition to six 0.50 caliber machine guns in the nose, early A-26B also had one or two more 0.50 caliber guns mounted in pods under each wing. The top turret could also be locked forward and fired by the pilot, giving a maximum forward fire of 12 heavy machine guns. For defense, the gunner controlled both the top and bottom gun turrets through a periscopic sight, with a view both above and below the fuselage, as required.
With a maximum weight of 35,000 lbs, early production A-26s had a top speed of 355 mph at 15,000 feet, but this dropped to 322 mph at 10,000 feet in later A-26Bs which had a gross weight of 41,000 lbs, including 6,000 lbs of bombs and more fuel.
The first Invaders to see combat were A-26Bs flying low-level attack missions in New Guinea in the spring of 1944 (see John Henebry's oral history in this issue). Their crews complained of poor visibility, especially to the sides from the cockpit and a lack of forward firepower for ground attack and strafing missions. The original A-26 cockpit had a flattened top with only one forward-hinged upward opening hatch on the right side, from which quick escape was difficult for the pilot. A new cockpit with outward hinged clear "clamshell" openings was quickly developed, which also improved the pilot's visibility.
To improve the forward gun fire, a new eight gun nose was designed with the 0.50 caliber guns in two vertical rows, and three more mounted in the wings, instead of in drag-producing pods, giving a forward fire of 16 guns, including the top turret.
When the Ninth Air Force first tried A-26Bs in the medium bomber role in Europe in the fall of 1944, the original canopy was not as great a problem as in the strafing roll. Thus European commands were equipped with early production A-26s, while improved Invaders with the clamshell canopies and heavier forward fire were earmarked for the Army's Pacific commands.
Douglas test pilot William Morrisey took the first of the new improved Invaders to the Pacific (see his oral history elsewhere in this issue). Morrisey demonstrated the aircraft and let other pilots fly on each demo flight (changing from the jump seat to the single pilot's seat in flight), and even went on missions to attack Japanese targets on Formosa. With an attack speed of 350 mph and the improved cockpit and firepower, the A-26 was superior to the A-20 and B-25, and had the war required an invasion of the Japanese homeland, the Invader's role would have been significant.
In Europe, conversion from the A-20 to the A-26 began in Nov. 1944 in the Ninth Air Force, while one bomb group of the Twelfth Air Force in Italy operated with both Douglas bombers from Feb. 1945 until the defeat of Germany in May.
At the end of the Second World War, the Douglas A-26 was the most modern attack aircraft in the USAF's inventory. With the coming of peace, however, orders were cancelled or drastically reduced after only about 2,452 had been built. The Invader equipped the few light and medium bomber units of the USAF in 1947, with the new designation B-26. When war broke out in Korea in June 1950, Invaders of the 3rd BG based in Japan once again went to war. One of the most difficult missions flown in Korea was that of night interdiction, and many of the Invader's sorties were flown at night.
One source credits the Invaders of the 3rd and 17th Bomb Wings with 55,000 sorties, with claims for the destruction of over 38,000 vehicles, over 4,000 railroad cars or locomotives and seven enemy aircraft during the fighting in Korea. To supply the active squadrons, many A-26s that had been transferred to the National Guard, Reserves, U. S. Navy and even some sold for surplus had to be reactivated or used for spare parts.
After Korea, the Invaders were replaced in front-line service by jet-powered bombers, but the new era of counter insurgency or "brush wars" gave them a new lease on life. The USAF's 1st Air Commando Group found the Invader valuable in this role, but the age of the aircraft was showing, and wing failures were a problem. To solve the problem, the Air Force decided to order improved Invaders from On Mark Engineering of Van Nuys, CA.
On Mark had developed an executive transport version of the Invader for civilian use, and their remanufactured B-26K Counter Invader featured a spar strap to strengthen the wings, 2,500 hp P&W R-2800-52W engines with fully-reversing propellers, dual flight controls and many other improvements. The Air Force ordered forty B-26Ks to be modified from existing B-26 Invaders. While in service in Southeast Asia in the 1960s, the reworked B-26Ks were redesignated A-26As, supposedly to prevent the aircraft from being referred to as bombers while based in some host countries such as Thailand.
Douglas' Invader carried a number of other designations over its long career, including the FA-26C night reconnaissance version, equipped with radar and cameras, and various utility, drone and target towing/launching versions.The U. S. Navy used 150 surplus A-26Cs as JD-1 target tugs. Fitted with higher-powered engines, A-26D and E models were ordered but cancelled before deliveries began. The single XA-26F had a GE J31 turbojet mounted in the tail, and served mostly as a flying test bed.
The last Invaders left active U. S. service in about 1972, largely for lack of spare parts to keep them flying. A number of foreign air forces also operated Invaders after World War II, and in civilian hands, they proved useful for aerial mapping and surveying, aerial fire fighting and as a fast executive transport.
Call it the A-26, B-26 or just the Invader, very few WWII combat aircraft can match the Douglas bomber's performance and service record of nearly three decades.
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