Douglas A-26B Invader
WWII Twin-engine mid-wing light attack bomber, U.S.A.

Archive Photos ^1,2

Douglas A-26B-20-DL Invader (AF 41-39221, c/n 6934, N9636C/N3035S/N256H/N26GT, On Mark Marksman) on display (11/22/2011) at South Mountain Hight School, Phoenix, Arizona (11/22/2011 photos by Lt. Col. Dr. Marc Matthews, M.D., USAF (retired)) ¹

Douglas A-26B-66-DL Invader (AF 44-34722, c/n 28001, NX3222T) on display (4/14/2004) at the Tillamook Air Museum, Tillamook, Oregon (Photos by John Shupek) copyright © 2004 Skytamer Images) ²

Douglas A-26B Invader Grim Reaper (AF 44-35617, c/n 28896) on display (11/20/2001) at the Hill Aerospace Museum, Hill Air Force Base, Roy, Utah (Photos by John Shupek)²

Douglas A-26B-61-DL Invader LuLu (AF 44-34520, c/n 27799, N126HP, 1944) on display (11/20/2011) at the Lauridsen Aviation Museum, Buckeye, Arizona (Photos by Lt. Col. Dr. Marc Matthews, M.D., USAF (retired))¹

Douglas B-26B-61-DL Invader (AF 44-34609, c/n 27888, N4819E) on display (11/20/2011) at the Lauridsen Aviation Museum, Buckeye, Arizona (Photos by Lt. Col. Dr. Marc Matthews, M.D., USAF (retired))¹

Overview ³

• Douglas A-26 Invader
• Role: Ground attack, Light bomber
• Manufacturer: Douglas Aircraft Company
• First flight: 10 July 1942
• Retired: 1980 Colombian Air Force
• Primary users: United States Army Air Forces
• United States Air Force
• United States Navy
• French Air Force
• Number built: 2,503
• Unit cost: US$242,595 (1942)
• Variants: On Mark Executive, Marketeer, and Marksman

The Douglas A-26 Invader (designated B-26 between 1948 and 1965) is an American Twin-engine light bomber and ground attack aircraft. Built by Douglas Aircraft Company during World War II, the Invader also saw service during several major Cold War conflicts. 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.

A re-designation of the type from A-26 to B-26 led to confusion with the Martin B-26 Marauder, which first flew in November 1940, some 20 months before the Douglas design’s maiden flight. Although both types were powered by the widely used Pratt & Whitney R-2800 Double Wasp eighteen-cylinder, double-row radial engine, they were completely different and separate designs - the Martin bomber originated in 1939, with more than twice as many Marauders (nearly 5,300) produced in comparison to the Douglas design.

Design and Development ³

The Douglas A-26 Invader was an unusual design for an attack bomber of the early 1940s period, as it was designed as a single-pilot aircraft (sharing this characteristic with the RAF’s de Havilland Mosquito, among others). The aircraft was designed by Edward Heinemann, Robert Donovan, and Ted R. Smith. The project aerodynamicist on the program was A.M.O. Smith, who designed the wing making use of the then-new NACA 65-215 laminar flow airfoil.

The Douglas XA-26 prototype (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 there were problems with engine cooling which led to cowling changes and omission of the propeller spinners on production aircraft, plus modification of the nose landing gear after repeated collapses during testing.

The Douglas A-26 Invader was originally built in two different configurations. The Douglas A-26B had a solid nose, which originally could be equipped with a combination of anything from .50 caliber machine guns, 37-mm auto cannon, 20-mm or even a 75-mm pack howitzer, but normally the solid nose version housed six (or later eight) .50 caliber machine guns, officially termed the all-purpose nose, later commonly known as the six-gun nose or eight-gun nose. The Douglas A-26C’s glass nose, officially termed the Bombardier nose, contained a Norden bombsight for medium altitude precision bombing. The Douglas A-26C nose section included two fixed M-2 guns, later replaced by underwing gun packs or internal guns in the wings.

After about 1,570 production aircraft, three guns were installed in each wing, coinciding with the introduction of the eight-gun nose for Douglas A-26B’s, giving some configurations as many as 14 .50 in (12.7 mm) machine guns in a fixed forward mount. An A-26C nose section could be exchanged for an A-26B nose section, or vice versa, in a few man-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.

Alongside the pilot in an Douglas A-26B Invader, a crew member typically served as navigator and gun loader for the pilot-operated nose guns. In the Douglas A-26C Invader, that crew member served as navigator and bombardier, and relocated to the nose section for the bombing phase of an operation. A small number of Douglas A-26C Invaders were fitted with dual flight controls, some parts of which could be disabled in flight to allow limited access to the nose section. A tractor-style jump seat was located behind the navigator’s seat. In most missions, a third crew member in the rear gunner’s compartment operated the remotely-controlled dorsal and ventral gun turrets, with access to and from the cockpit only possible via the bomb bay when that was empty.

Operational History ³

World War II

The Douglas company began delivering the production model Douglas A-26B Invader in August 1943 with the new bomber first seeing action with the Fifth Air Force in the Southwest Pacific theater on 23 June 1944, when they bombed Japanese-held islands near Manokwari. The pilots in the 3rd Bomb Group’s 13th Squadron, The Grim Reapers, who received the first four Douglas A-26 Invaders for evaluation, found the view from the cockpit to be poor for low level attack. General George Kenney, commander of the Far East Air Forces stated that, We do not want the A-26 under any circumstances as a replacement for anything. Until changes could be made, the 3rd Bomb Group requested additional Douglas A-20 Havocs, although both types were used in composite flights. The 319th Bomb Group worked up on the Douglas A-26 Invader in March 1945, joining the initial 3rd BG, with the 319th flying until 12 August 1945. The Douglas A-26 Invader operations wound down in mid-August 1945 with only a few dozen missions flown.

Douglas A-26 Invaders began arriving 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 its first mission on 6 September 1944. The first group to fully convert to the Douglas A-26B Invader was 416th Bombardment Group with which it entered combat on 17 November, and the 409th Bombardment Group, whose Douglas A-26 Invaders became operational in late November. Due to a shortage of Douglas A-26C Invader variants, the groups flew a combined Douglas A-20 Havoc;/Douglas A-26 Invader unit until deliveries of the glass-nose version caught up. Besides bombing and strafing, tactical reconnaissance and night interdiction missions were undertaken successfully. In contrast to the Pacific-based units, the Douglas A-26 Invader was well received by pilots and crew alike, and by 1945, the 9th AF had flown 11,567 missions, dropping 18,054 tons of bombs, recording seven confirmed kills while losing 67 aircraft.

Postwar Era

The USAF Strategic Air Command had the renamed Douglas B-26 Invader (RB-26) in service from 1949 through 1950, the Tactical Air Command through the late 1960’s, and the last examples in service with the Air National Guard through 1972. The US Navy also used a small number of these aircraft in their utility squadrons for target towing and general utility use until superseded by the DC-130A variant of the Lockheed C-130 Hercules. The Navy designation was JD-1 and JD-1D until 1962, when the JD-1 was redesignated UB-26J and the JD-1D was redesignated DB-26J.

Korean War

Douglas B-26 Invaders of the 3rd Bombardment Group, operating from bases in Southern Japan, were some of 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 when they bombed an airfield outside of Pyongyang.

On 10 August 1950, the 452nd Reserve Bomb Wing was activated for Korean Service. This was the first time that an entire air force unit had ever been activated. It flew its first missions in November 1950 from Itazuke Japan doing daylight support with the 3rd Bomb Wing flying night missions. Because of the Chinese intervention it was forced to find another base and moved to Miho Air base on the west coast of Honshu. In early 1951 it moved to East Pusan Air Base and continued its daylight as well as night intruder missions. In June 1951, it joined the 3rd Bomb Wing in night activity only, dividing the target areas with the 452nd taking the eastern half and the 3rd the western. For its efforts in the Korean War, it was awarded 2 Unit Citations and the Korean Presidential Citation. It also received credit for eight Campaign Operations. In May 1952 it was inactivated and all of its aircraft and equipment along with its regular air force personnel were absorbed by the 17th Bomb Wing. During its time as an active unit, the 452nd flew 15,000 sorties (7000 at night) with a loss of 85 crewmen.

Douglas B-26 Invaders were credited with the destruction of 38,500 vehicles, 406 locomotives, 3,700 railway trucks, and seven enemy aircraft on the ground. On 14 September 1951, Captain John S. Walmsley, Jr. attacked a supply train. When his guns jammed, he illuminated the target with his searchlight to enable his wingmen to destroy the train. Walmsley was shot down and posthumously awarded the Medal of Honor. Invaders carried out the last USAF bombing mission of the war 24 minutes before the Armistice Agreement was signed on 27 June 1953.

In addition to the standard attack versions of the Douglas B-26 Invader which flew night interdiction missions, a small number of modified WB-26s and RB-26s of the 67th Tactical Reconnaissance Wing flew critical weather observation and reconnaissance missions in supporting roles.

First Indochina War

In the 1950s, the French Air Force’s (Armée de l’air) Bombing Groups (Groupe de bombardment) including GB 1/19 Gascogne and GB 1/25 Tunisia used USAF-lent Douglas B-26 during the First Indochina War. Cat Bi (Haiphong) based Douglas B-26 Invaders operated over Dien Bien Phu in March and April 1954 during the siege of Dien Bien Phu. In this period, a massive use of Philippines based USAF Douglas B-26 Invaders against the Viet Minh heavy artillery was planned by the U.S. and French Joint Chief of Staff as Operation Vulture, but was eventually canceled by the respective governments.

Indonesia

In 1958, the CIA started Operation Haik in Indonesia, concerned about the Sukarno regime’s communist leanings. At least a dozen Douglas B-26 Invaders were committed in support of rebel forces. On 18 May 1958, American contract pilot Allen Pope’s Douglas B-26 Invader was initially hit by anti-aircraft ground fire and then brought down by a North American P-51 Mustang flown by Capt. Ignatius Dewanto (the only known air-to-air kill in the history of the Indonesian Air Force). The capture and trial of Lieutenant Pope brought a quick end to Operation Haik, but the capabilities of the Invader were not lost on the Indonesian government. In 1959, the government purchased six aircraft at Davis-Monthan AFB and these were ferried to Indonesia in full military markings during mid-1960. These aircraft would have a long career and were utilized in a number of actions against rebels in various areas. The last operational flights of the three survivors was in 1976 supporting the Indonesian invasion of East Timor. In 1977, the last two flyers were retired.

Service with the USAF in Southeast Asia

The first Douglas B-26 Invaders to arrive in Southeast Asia were deployed to Takhli RTAFB, Thailand in December 1960. These unmarked aircraft, operated under the auspices of the U.S. CIA (Central Intelligence Agency), were soon augmented by an additional 16 aircraft, 12 Douglas B-26B Invaders and Douglas B-26C Invaders plus four Douglas RB-26C Invaders under Operation Mill Pond. The mission of all of these aircraft was to assist the Royal Lao Government in fighting the Pathet Lao. The repercussions from the Bay of Pigs invasion meant that no combat missions are known to have been flown, although Douglas RB-26C Invaders operated over Laos until the end of 1961. The aircraft were subsequently operated in South Vietnam under Project Farm Gate. The only other deployment of Douglas B-26 Invader aircraft to Laos prior to the introduction of the Douglas B-26K/A-26A Counter Invader, was the deployment of two Douglas RB-26C Invader aircraft, specifically modified for night reconnaissance, deployed to Laos between May and July 1962 under Project Black Watch. These aircraft, initially drawn from Farm Gate stocks, were returned upon the end of these missions.

The aircraft from Laos participated in the early phase of the Vietnam War with the USAF, but with Vietnamese markings as part of Farm Gate. Though Farm Gate operated Douglas B-26B Invaders, Douglas B-26C Invaders, and genuine Douglas RB-26C Invaders, many of these aircraft were operated under the designation Douglas RB-26C Invader, though they were used in a combat capacity. During 1963, two Douglas RB-26C Invaders were sent to Clark AB in the Philippines for modifications, though not with night systems as with those modified for Black Watch. The two aircraft returned from Black Watch to Farm Gate were subsequently given the designation RB-26L to distinguish them from other modified RB-26C, and were assigned to Project Sweet Sue. Farm Gate’s B-26 Invaders operated alongside the other primary strike aircraft of the time, the North American T-28 Trojan, before both aircraft types were replaced by the Douglas A-1 Skyraider. The Douglas B-26 Invaders were withdrawn from service in February 1964 after two accidents related to wing spar fatigue, one during combat in Southeast Asia in August 1963 and one during an airpower demonstration at Eglin AFB, Florida in February 1964.

On 11 February 1964, two pilots from the 1st Air Commando Wing stationed at Hurlburt Field, Florida, died in the crash of a Douglas B-26 Invader on Range 52 at Eglin AFB when it lost a wing during pull-out from a strafing pass. The aircraft was participating in a demonstration of the Special Air Warfare Center’s counter insurgency capabilities and had completed a strafing run when the accident occurred. SAWC had presented the demonstration on an average of twice each month for the previous 21 months. Douglas B-26 Invader aircraft used by USAF Commandos in Vietnam were grounded 8 April 1964, following an official investigation into the 11 February accident. Douglas B-26 Invader aircraft in use by the Vietnamese Air Force were also grounded in accordance with the U.S. ruling.

In response to this, the On Mark Engineering Company of Van Nuys, California was selected by the Air Force to extensively upgrade the Invader for a counter-insurgency role. The first production flight of the On Mark B-26K Counter-Invader was on 30 May 1964 at the Van Nuys Airport. On Mark converted 40 Invaders to the new B-26K Counter-Invader standard, which included upgraded engines, propellers, and brakes, re-manufactured wings, and wing tip fuel tanks, for use by the 609th Special Operations Squadron. In May 1966, the On Mark B-26K Counter-Invader was re-designated A-26A/K 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. Two of these aircraft were further modified with a Forward Looking Infrared (FLIR system) under project Lonesome Tiger, as a part of Operation Shed Light.

Bay of Pigs Invasion

In early 1961, about 20 Douglas B-26B Invaders, most converted from B-26C configuration, were ’sanitized’ at Duke Field (aka Auxiliary Field Three at Eglin AFB). They had defensive armament removed, and were fitted with the eight-gun nose, underwing drop tanks, and rocket racks. They were flown to a CIA-run base in Guatemala where training was underway of Douglas B-26 Invader, Douglas C-46 Commando and Douglas C-54 Skymaster Cuban exile air crews by personnel from the Alabama ANG (Air National Guard). After transfer to Nicaragua in early April 1961, they were painted in the markings of the FAR (Fuerza Aérea Revolucionaria), the air force of the Cuban government. On 15 April 1961, crewed by Cuban exiles, eight Douglas B-26 Invaders of the FAL (Fuerza Aérea de Liberación) attacked three Cuban airfields, in an attempt to destroy FAR combat aircraft on the ground. On 17 April 1961, FAL Douglas B-26 Invaders supported the seaborne Bay of Pigs Invasion of Cuba. The conflict ended on 19 April, after the loss of nine FAL Douglas B-26 Invaders, 10 Cuban exiles and 4 American aircrew in combat. The FAR flew Douglas B-26C Invaders in the conflict, one of which was shot down by a CIA ’command ship’ with the loss of 4 Cuban aircrew.

Africa in the 1960’s

The CIA contracted pilots, some previously employed during the Bay of Pigs Invasion, flew On Mark B-26K Counter-Invaders for ground attack against Simba rebels in the Congo Crisis. New production On Mark B-26K Counter-Invaders were delivered to the Congo via Hurlburt Field in 1964.

The Portuguese Air Force purchased Invaders covertly for use in Portuguese Angola in 1965, during the Portuguese Colonial War.

Biafra used two provisionally armed B-26 Invaders in combat during Nigerian Civil War in 1967, flown among others by Jan Zumbach.

Variants ³

Military Variants

The large majority of the A-26/B-26 Invader’s production run of 2,452 were early A-26Bs and A-26Cs.

• XA-26: Serial no. 41-19504 served as the prototype for the series; initially flown with dummy armament.
• XA-26A: Serial no. 41-19505 served as a prototype night fighter with a crew of two-pilot plus radar-operator/gunner
• XA-26B: Serial no. 41-19588 was a prototype "solid-nosed" attack variant with crew of three: pilot, gun loader/navigator (in front cockpit) plus gunner in rear, and carrying a forward firing 75 mm (2.75 in) cannon.
• A-26B: Attack bomber with solid nose carrying six or eight 0.50 in (12.7 mm) machine guns. Production totals: 1,355 A-26Bs were built and delivered, 205 at Tulsa, Oklahoma (A-26B-5-DT to A-26B-25-DT) plus 1,150 at Long Beach, California (A-26B-1-DL to A-26B-66-DL). About 24 more airframes were built at Long Beach but not delivered to USAAF, some of those later sold to other civil and military customers. A-26B was redesignated B-26B with USAF in 1948.
• TB-26B: Unarmed variant converted from B-26B for training purposes.
• VB-26B: Unarmed variant converted from B-26B for administrative purposes.
• A-26C: Attack bomber. Production totals: 1,091 A-26Cs were built and delivered, five at Long Beach, California (A-26C-1-DL and A-26C-2-DL) plus 1,086 at Tulsa, Oklahoma (A-26C-16-DT to A-26B-55-DT). About 53 more airframes were built at Tulsa but not delivered to USAAF, some of those later sold to other civil and military customers. A-26C was redesignated B-26C with USAF in 1948.
• RB-26C: Unarmed photo reconnaissance variant converted from B-26C; it carried cameras and flash flares for night photography. Designated FA-26C prior to 1962.
• TB-26C: Unarmed variant converted from B-26C for training purposes.
• XA-26D: Serial no. 44-34776 prototype for the proposed A-26D attack bomber with uprated Chevrolet manufactured R-2800-83 engines, and late model A-26B armament of eight 0.50 in (12.7 mm) machine guns in solid nose and six 0.50 in (12.7 mm) guns in the wing; series of 750 A-26Ds was canceled after V-J Day.
• XA-26E: Serial no. 44-25563 prototype for the A-26E attack bomber. As with the XA-26D but with an A-26C-type glass nose; a contract for 2,150 A-26E-DTs was canceled following V-J Day.
• XA-26F: Serial no. 44-34586 prototype for a high-speed A-26F powered by two 2,100 hp (1,600 kW) R-2800-83 engines driving four-bladed propellers with a 1,600 lbf (7.1 kN) s.t. General Electric J31 turbojet installed in the rear fuselage. The prototype reached a top speed of 435 mph (700 kph) but the series was canceled as performance gains were not sufficient.
• A-26Z: Unofficial designation for a proposed postwar production version of the A-26. It was to have a more powerful version of the Pratt & Whitney R-2800 radial engine and was to be fitted with such features as a raised pilot’s cockpit canopy, an improved cockpit arrangement and wingtip drop tanks. If produced, the unglazed nose version would have been designated A-26G and the glazed nose version A-26H. However, in October 1945, the USAAF concluded that there were enough A-26 aircraft to meet postwar needs, consequently, the "A-26Z" version was not produced.
• JD-1: US Navy version with one A-26B (44-34217) and one A-26C (44-35467) redesignated during World War II, postwar, 150 surplus A-26s for use by land-based utility squadrons as target tugs and later, drone directors (designated JD-1D) and general utility aircraft. In 1962, the JD-1 and JD-1D were redesignated UB-26J and DB-26J respectively.
• YB-26K: On Mark Engineering prototype for refurbished attack bomber; modifications included rebuilt, strengthened wings, enlarged tail assembly, new R-2800-103W engines with reversible propellers/propeller spinners, dual controls, wingtip tanks, newer avionics and increased hardpoint/armament enhancements.
• B-26K/A-26A: Counter Invader (64-17675) B-26K On Mark Engineering conversions of 40 B-26Bs or TB-26Bs with two B-26Cs and a single JB-26C; changes included fitting of 2,500 hp (1,900 kW) R-2800-52W engines with no propeller spinners and the six wing guns deleted. During operations in Vietnam, in May 1966, the aircraft were reassigned the old attack designation of A-26A. The A-26As were retired in 1969 when they had reached the safe limits of allotted flying time.
• RB-26L: Two RB-26Cs (44-34718 and 44-35782) modified for night photography missions.
• B-26N: Unofficial designation applied to B-26s operated by the French Air Force (Armée de l’air) in Algeria as night fighters. These aircraft were modified B-26Cs fitted with AI Mk × radar taken from obsolete Meteor NF.11 night fighters, two underwing gun packs each with two 0.50 in (12.7 mm) m² Browning machine guns and SNEB rocket pods.

Third Party Civil Variants

Since 1945, over 300 A-26s have been entered on to the FAA US Civil Aircraft Register. Perhaps up to a hundred of those were probably only registered for ferry flights from USAF bases such as Davis-Monthan AFB, AZ and Hill AFB, UT to civil airports and stored as candidates for sale on the civil or overseas military markets.

The initial main civil uses were as "executive" personnel transports with minimal modifications such as removal of military features, bomb bay doors sealed shut, passenger entry stairs in bomb bay, and the conversion of the fuselage to accept six to eight passengers. Improvements developed considerably until the early 1960s, when purpose-built executive types such as the (turboprop) Gulfstream started to become available.

During the mid-1950s, A-26s were tested and used as air tankers for suppression of forest and wildland fires, and may have briefly used borate-based retardants, hence the inaccurate and unofficial term "borate bombers." Borate was soon discontinued due to its undesirable ecologic effects, replaced with retardant mixtures of water, clays, fertilizers and red dyes. That use of A-26s on USDA contracts was discontinued in major regions by about 1973, when many of the A-26 air tankers then found willing purchasers in Canada.

Much early development of conversions was carried out by Grand Central Aircraft, whose drawings and personnel were taken up by the On Mark Engineering Company of Van Nuys, California from about 1955. By the 1960s, On Mark had obtained an exclusive licence from Douglas Aircraft Company for manufacture and sale of parts for A-26s. The On Mark Executive (1956), the On Mark Marketeer (1957), and the more radical pressurized On Mark Marksman (1961) were products of this effort.

The next most significant conversion was the Rock Island Monarch 26, while less numerous and more basic conversions for executive operations were carried out by Wold Engineering, LB Smith Aircraft Corp., R. G. LeTourneau Inc, Rhodes-Berry Company and Lockheed Aircraft Service Inc.

Garrett AiResearch used two A-26 variants as testbeds for turbine engines; see also XA-26F above.

Douglas A-26B Invader Technical Data ⁴

References

1. Photos: Lt. Col. Dr. Marc Matthews, M.D., USAF (retired) 11/22/2011)
2. Shupek, John. Photos, copyright © 2001, 2004 Skytamer Images. All Rights Reserved
3. Wikipedia, the free encyclopedia. Douglas A-26 Invader
4. Swanborough, Gordon and Peter M. Bowers. United States Military Aircraft since 1908, London: Putnam & Company Limited, 1971, ISBN 0-370-00094-3, Pg. 261.