The Douglas A-26 Invader (designated B-26 between 1948 and 1965) is an American twin-engined light bomber and ground attack aircraft. Built by Douglas Aircraft Company during World War II, the Invader also saw service during the Korean and Vietnam wars. A limited number of highly modified United States Air Force aircraft served in Southeast Asia until 1969. It was a fast aircraft capable of carrying a large bomb load. A range of guns could be fitted to produce a formidable ground-attack aircraft.Wheeler 1992, p. 82.
A redesignation of the type from A-26 to B-26 has led to confusion with the earlier and unrelated medium bomber Martin B-26 Marauder, which had already been withdrawn from service when the designation was reused.
Design and development
The A-26 was Douglas Aircraft's successor to the A-20 (DB-7) Havoc, also known as Douglas Boston. Designed by Ed Heinemann, Robert Donovan, and Ted R. Smith,Francillon 1979 the innovative NACA 65-215 laminar-flow airfoil wing of the A-26 was the work of project aerodynamics expert A.M.O. Smith.Smith, A.M.O., "High-Lift Aerodynamics; the 37th Wright Brothers Lecture", AIAA paper 74-939, reprinted in the AIAA Journal of Aircraft, Vol. 12 No. 6, June 1975.Lednicer, David. The Incomplete Guide to Airfoil Usage. Champaign, Illinois: UIUC Applied Aerodynamics Group, 2010. Retrieved: 18 May 2011
The Douglas XA-26 prototype (AAC Ser. No. 41-19504) first flew on 10 July 1942 at Mines Field, El Segundo, with test pilot Benny Howard at the controls. Flight tests revealed excellent performance and handling but engine-cooling problems led to cowling changes and elimination of the propeller spinners on production aircraft. During testing, the nose wheel was found to be structurally inadequate, so it was strengthened.Mesko 1980, p. 5.
The early A-26 versions were built in two forms The A-26B gun-nose could be equipped with a combination of armament, including .50 caliber (12.7 mm) machine guns, auto cannon, or an experimental pack howitzer (never used operationally). The 'B' gun-nose version housed six (and later, eight) .50 caliber machine guns, officially the "all-purpose nose", later known as the "six-gun nose" or "eight-gun nose". The A-26Cs "glass" "Bombardier nose", contained a Norden bombsight for medium-altitude precision bombing. The A-26C nose section included two fixed M-2 guns, but those were eliminated after underwing gun packs or internal guns in the wings proved effective during colder weather.Borland, Hal. "Plane of Many Faces". Popular Science, July 1945.
After about 1,570 production aircraft, three guns were installed in each wing, coinciding with the introduction of the "eight-gun nose" for A-26Bs, giving some versions as many as fourteen machine guns in fixed forward mounts. An A-26C nose section could be replaced with an A-26B nose section, or vice versa, in a few hours, thus physically (and officially) changing the designation and operational role. The "flat-topped" canopy was changed in late 1944 after about 820 production aircraft, to a clamshell style with greatly improved visibility.Winchester 2004, p. 75.Thompson 2002
Alongside the pilot in an A-26B, a crew member served as navigator and gun loader for the pilot-operated nose guns. In an A-26C, that crew member served as navigator and bombardier, and moved to the nose section to bomb. A few A-26Cs were fitted with dual flight controls, some parts of which could be disabled in flight for access to the nose section. Access for the bombardier was through the lower section of the right instrument panel; he normally sat next to the pilot. This was similar to British designs such as the Lancaster, Blenheim/Beaufort and Wellington. A tractor-style "jump seat" was behind the "navigator's seat". In most missions, a third crew member in the rear gunner's compartment operated the remote-controlled dorsal and ventral gun turrets, with access to-and-from the cockpit via the bomb bay only if that was empty. The gunner operated both dorsal and ventral turrets via a novel, complex and unreliable dual-ended periscope sight, a vertical column running through the center of the rear compartment, with traversing and elevating/depressing periscope sights on each end. The gunner sat on a seat facing rearwards looking into a binocular periscope sight mounted on the column, controlling the guns with a pair of handles on the sides of the column. Aimed above the centerline of the aircraft, the mirror in the center of the column 'flipped', showing the gunner a limited view similar to the view the upper periscope was seeing. As he pressed the handles downward, and as the bead passed the centerline, the mirror automatically flipped, transferring the sight "seamlessly" to the lower periscope. The guns aimed in the approximate direction the periscope was aimed, automatically transferring between upper and lower turrets as required, and computing for parallax and other factors. While novel and sound in principle, the developers invested a great deal of time and effort in their attempts to get the system to work, delaying production. As might be expected, the complex system was difficult to maintain in the field.Johnsen 1999
Operational history
World War II
Pacific Douglas officially delivered the first production model A-26B aircraft to the United States Army Air Forces (USAAF) on 10 September 1943.Thompson 2002, p. 34. These were sent for field evaluation in actual combat operations, with the Fifth Air Force in the Southwest Pacific theater. The A-26 first saw action on 23 June 1944, when four aircraft attached to the 3rd Bombardment Group's 13th Squadron ("The Grim Reapers"), bombed Japanese-held islands near Manokwari."June 1944". 43rd Bomb Group Association via kensmen.com, 1999. Retrieved: 2 August 2007. Aircrew from "The Grim Reapers", while evaluating these four A-26Bs, noted that downward views from the cockpit were significantly hindered by the nature of the design – especially the positioning of the engines – which made the A-26B unsuitable for its intended role of ground attack. In response to such evaluations, General George Kenney, commander of the Far East Air Forces, stated: "We do not want the A-26 under any circumstances as a replacement for anything."O'Leary 2002, p. 42. Nevertheless, development continued. While the 3rd BG was waiting suitably modified A-26s, it requested additional Douglas A-20 Havocs, although both types were used in composite flights.Mesko 1980, p. 17.
Some USAAF units in the Pacific that operated either the A-20 or B-25 received the A-26 for trials in limited quantities.
The 319th Bomb Group was fully converted to the A-26 in March 1945, when it commenced operations with the 3rd BG. In August, after a few dozen A-26 missions, it became evident that the war was coming to an abrupt close, and operations began to wind down. The 319th officially ceased combat operations on 12 August 1945.
Europe
Douglas needed better results from the Invader's second combat test, so ferried A-26s arrived in Europe in late September 1944 for assignment to the Ninth Air Force. The initial deployment involved 18 aircraft and crews assigned to the 553d Squadron of the 386th Bomb Group. This unit flew their first mission on 6 September 1944. No aircraft were lost on the eight test missions, and the Ninth Air Force announced they were satisfied, eventually replacing their A-20s and B-26s with the A-26 Invader.
The first group to convert to the A-26B was 416th Bombardment Group. With it, they entered combat on 17 November, and the 409th Bombardment Group, whose A-26s became operational in late November. Due to a shortage of A-26C variants, the groups flew a combined A-20/A-26 unit until deliveries of the glass-nosed version caught up. Besides bombing and strafing, tactical reconnaissance and night interdiction missions were successful. In contrast to the Pacific-based units, the A-26 was well received by pilots and crew alike, and by 1945, the 9th AF had 11,567 missions, dropping 18,054 tons of bombs, recording seven confirmed kills while losing 67 aircraft.Mesko 1980, p.12.
In Italy, the Twelfth Air Force's 47th Bomb Group also received the A-26 starting in January 1945. They were used against German transport links, and for direct support and interdiction against tanks and troop concentrations in the Po Valley in the final campaigns in Italy.
Postwar era
United States With the establishment of the United States Air Force (USAF) as an independent service in 1947, the Strategic Air Command operated the again redesignated B-26 as an RB-26 reconnaissance aircraft in service 1949 to 1950. The US Air Forces in Europe continued operating the B-26 until 1957. Tactical Air Command operated the aircraft as both a B-26 and later designated back to A-26; the final variant was designated B-26K until 1966, then it again became the A-26A. This final version continued in service through the late 1960s with active-duty special-operations TAC units, and through 1972 with TAC-gained special-operations units of the Air National Guard.
The US Navy obtained Invaders from the USAF to use these aircraft in their utility squadrons (VU) for target towing and general utility until superseded by the DC-130A variant of the C-130 Hercules. The Navy designation was JD-1 and JD-1D until 1962, then the JD-1 was redesignated UB-26J. The JD-1D was also used under the designation of DB-26J. The CIA also used the type for covert operations.Weiner, T. (2007). Legacy of ashes: The history of the CIA. Doubleday, New York, NY, pp. 150-151.
The last A-26 in active US service was assigned to the Air National Guard; that aircraft was retired from military service in 1972 by the USAF and the National Guard Bureau, and donated to the National Air and Space Museum.Douglas B-26K (A-26) Counter Invader National Museum. Retrieved 21 December 2022
Korean War
B-26 Invaders of the 3rd Bombardment Group, operating from bases in southern Japan, were among the first USAF aircraft engaged in the Korean War, carrying out missions over South Korea on 27 and 28 June, before carrying out the first USAF bombing mission on North Korea on 29 June 1950, bombing an airfield near Pyongyang.Horne 1984, p. 50.
On 10 August 1950, the Air Force Reserve's 452d Bombardment Wing was activated for Korean service."452 Operations Group (AFRC)". Air Force Historical Research Agency, December 1997. Retrieved: 18 April 2010. It flew its first missions in November 1950 from Itazuke, Japan, providing daylight support, with the 3rd Bomb Wing, consisting of the 8th, 13th, and 90th Bomb Squadrons, flying night missions. Because of the Chinese intervention, they were forced to find another base, so they moved to Miho Air Base on the west coast of Honshū. In early 1951, they moved to Pusan East (K-9) Air Base, continuing their daylight and night-intruder missions. In June 1951, they joined the 3rd Bomb Wing, Kunsan (K-8), in night activity only, dividing the target areas, with the 452nd taking the eastern half and the 3rd the western. For their efforts in the Korean War, they received two unit citations and the Korean Presidential Citation. They also received credit for eight campaign operations.
In May 1952, they were inactivated. Their aircraft and equipment along with their personnel were absorbed by the 17th Bomb Wing. During their time as an active unit, the 452nd flew 15,000 sorties (7,000 at night) with a loss of 85 crewmen.