History of the Douglas A26 Invader

A-26 Invader

The Douglas A-26 Invader B-26 between 1948-1965) was a United States twin-engined light attack bomber built by the Douglas Aircraft Co. during World War II that also saw service during several of the Cold War’s major conflicts. A limited number of highly modified aircraft served in combat thru November 1969. The last A-26 was retired from military service in 1972 by the National Guard Bureau and donated to the National Air and Space Museum.

Design and development

The A-26 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). It was the first medium bomber designed with a laminar flow wing similar to the P-51 Mustang. This wing design coupled with the large engines resulted in the fastest medium bomber of WWII. The aircraft was designed by Edward Heinemann, Robert Donovan and Ted R. Smith.

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 collapses were experienced during testing.

The A-26 was originally built in two different configurations. The A-26B had a “solid” nose, which normally 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” augmented by four underwing twin gun packs or six internal guns in the wings. The A-26C ‘s “glass” nose, officially termed the “Bombardier nose”, contained a Norden bombsight for medium altitude precision bombing. The A-26C nose section included two fixed M-2 .50 caliber guns also augmented by four underwing twin gun packs or six 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 A-26Bs, giving some configurations as many as 14 .50 caliber 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. Numerous older aircraft were modified to this clamshell configuration.

Alongside the pilot in an A-26B, sometimes an additional crewmember served as navigator. In an A-26C, that crewmember served as navigator and bombardier, and relocated to the nose section for the bombing phase of an operation. A small number of A-26’s were fitted with dual flight controls to act as trainers. Another crewmember 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.

The aircraft had a long development due to many changes ordered by the Air Force and the intricate manufacturing process of the wing. Beech Aircraft won the contract to produce the wings for Douglas but there were delays in procuring the specialized machinery needed.

The Air Force recognized the versatility of the aircraft and attempted to adapt it to numerous missions. It was seen as a night fighter, bomber, attack aircraft and naval attack aircraft. The aircraft was capable of carrying two torpedoes internally but was never used as such in combat. It was faster, required only two or three crewmembers and carried more ordnance than current bombers. It also had superb single engine characteristics. It was decided that the Invader would replace all other medium bombers. With the end of WWII only the B-25 and A-26 were retained. The B-25 was relegated to training and utility duties while the A-26 was designated as the medium bomber for the Air Force.

A total of 2,452 Invaders were built at both Douglas plants. At the end of WWII the unit cost was $242,595.

Operational history

World War II

The Douglas Company began delivering the production model A-26B in August 1943. Invaders first saw action with the Fifth Air Force in the Southwest Pacific Theateon 23 June 1944, when they bombed Japanese -held islands near Manokwari. These initial aircraft had the flat canopies, which hindered pilot visibility and were not easy to bail out of. Combined with their weak nose gear and unique landing characteristics the aircraft was initially rejected by General Kenney. Further combat action in the Pacific was delayed until improvements were completed. The improved versions began arriving in late 1944 and began combat operations in early 1945.

Invaders began arriving in Europe in August 1944 for assignment to the 386 th Bomb Group, Ninth Air Force, and flew its first European combat mission on 6 Sep 1944 with a strike on targets near Brest. After initial combat trials the 386 th returned to their B-26 Marauders before completely converting to the A-26 in Feb 1945. The 391 st , 409 th , 410 th , 416 th then began converting to the Invader. The 319 th Bomb Group, 12 th AF, was transferred from the Mediterranean to Columbia AAF, SC, for conversion from the B-25 to the A-26. They were then deployed to Okinawa in July for Pacific Theater duty with the 7 th AF. The 47 th BG began converting in Jan 1945 while based in Italy.

Postwar era

With the formation of the USAF as a separate branch in 1947 the “A”, for attack, was dropped and the aircraft were redesignated as B-26’s. The original Martin B-26 Marauders had all been retired immediately after WWII. The USAF Strategic Air Command had the RB-26 in service from 1949 through 1950, the Tactical Air Command through the late 1960s, 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 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

The Invader became a prolific participant in this conflict. B-26 Invaders carried out the first USAF bombing mission of the Korean War on 29 June 1950 when they bombed an airfield outside of Pyongyang. B-26s 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 cease-fire was signed on 27 June 1953. The majority of the later war missions were night interdiction missions using single or two-ship flights. As such the aircraft rarely received publicity for the dangerous and lonely operations carried out in the mountainous terrain of Korea.

First Indochina War

In the 1950s, the French Air Force’s (Armée de l’Air) Bombing Groups including GB 1/19 Gascogne and GB 1/25 Tunisia used USAF-lent 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 B-26s against the Viet Minh heavy artillery was planned by the U.S. and French Joint Chief of Staff as for Operation Vulture, but it was eventually cancelled by the respective governments.

Service with the USAF in Southeast Asia

The first B-26s 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 B-26Bs and B-26Cs plus 4 RB-26Cs under Operation “Mill Pond”. The mission of all of these aircraft was to assist the Royal Lao Government in fighting the Pathet Lao. The aircraft were subsequently operated in South Vietnam under Project “Farm Gate”. The only other deployment of B-26 aircraft to Laos prior to the introduction of the B-26K/A-26A, was the deployment of two RB-26C 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 Project “Farm Gate”. Though Farm Gate operated B-26Bs, B-26Cs, and genuine RB-26Cs, many of these aircraft were operated under the designation RB-26C, though they were used in a combat capacity. During 1963, two RB-26C 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-26s operated alongside the other primary strike aircraft of the time, the T-28 Trojan, before both aircraft types were finally replaced by the A-1 Skyraider. The B-26s were withdrawn from service in early 1964 after two accidents were attributed to wing spar failure.

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 counterinsurgency role. The first production flight of the B-26K was on May 30, 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 1st Air Commando Group. In May 1966, the B-26K was re-designated A-26A for political reasons and deployed in Thailand to Nakhon Phanom (NKP) 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. The A-26’s continued in service thru November 1969 at Nakhon Phanom ( 609th Special Operations Squadron) and Bien Hoa in South Vietnam. Five were then transferred to the South Vietnamese Air Force to be used as instructional airframes at Nha Trang. They were still there in 1975 when South Vietnam collapsed.

Bay of Pigs Invasion

In April 1961, B-26s provided from U.S. military stocks were flown by Cuban exiles and CIA contract aircrews during the failed Bay of Pigs invasion

The CIA-backed Bay of Pigs invasion of Cuba was preceded by air attacks by B-26 bombers launched from Nicaragua and painted in the scheme of the Cuban Air Force. Their objective was to destroy Fidel Castro’s air force, mostly armed T-33 jet trainers provided to the Batista regime by the United States, on the ground. During April 15-16, 1961, B-26 raids met with mixed success in that they did not destroy most of the T-33 force, and Castro’s jets mauled one wave of B-26’s. Planned follow-up raids were cancelled after at least one American pilot, a member of the Alabama Air National Guard, was killed, assuring Castro of air superiority over the beachhead. While the Invaders failed to achieve their objective, their force was too small to accomplish it in three air raids, and after the first the element of surprise was lost.

Africa in the 1960s

CIA mercenary pilots, some previously employed during the Bay of Pigs Invasion, flew B-26Ks for ground attack against “Simba” rebels in the Congo Crisis. A few new production B-26K Counter-Invaders were delivered to the Congo via Hurlburt Field in 1964.

The Portuguese Air Force purchased Invaders covertly for use in Angola in 1965.

Biafra used two provisionally armed B-26s in combat during Nigerian Civil War in 1967.


Douglas/US 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 cannon.

A-26B: Attack bomber with solid nose carrying six or eight 0.50 in machine guns. An additional 6 or 8 .50 caliber machine guns were carried in or under the wings.

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 1947.

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 with glass nose for a bombardier. The glass nose had provisions for 2, fixed, .50 caliber machine guns installed in the right side of the nose. An additional 6 or 8 .50 caliber machine guns were carried in or under the wings.

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 1947.

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-inch machine guns in solid nose and six 0.50-inch guns in the wing. This series of 750 A-26Ds was cancelled 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 cancelled following V-J Day.

XA-26F: Serial no. 44-34586 prototype for a high-speed A-26F powered by two 2,100 hp R-2800-83 engines, driving four-bladed propellers, with a 1,600 lb.s.t. General Electric J31 turbojet installed in the rear fuselage. The prototype reached a top speed of 435 mph but the series was cancelled 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-26Gand 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: 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 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 B-26 was redesignated the A-26, because Thailand would not allow bombers to fly from their airfields, but they would allow attack aircraft to do so. ] The A-26As were finally retired at the end of 1969.

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 X radar taken from obsolete Meteor NF 11 night fighters, two underwing gun packs each with two 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-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 started to be tested and used as air tankers for suppression of forest and wild land fires, and may have briefly used borate-based retardants, hence the inaccurate and unofficial term “borate bombers.” Borate was soon discontinued due to sterility and toxicity and 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 license from Douglas Aircraft Company for manufacture and sale of parts for A-26s. The combination of a range of civil conversion options was the On Mark Executive in about 1956, followed by the On Mark Marketeer in 1957, and the more radical pressurized On Mark Marksman in 1961.

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

Operators (Military and Civilian)

Biafra, Brazil, Chile, Columbia, Dominican Republic, El Salvador, France, Guatemala, Indonesia, Nicaragua, Portugal, Saudi Arabia, South Vietnam, Turkey, United Kingdom, USA


Approximately 60 are now listed on the FAA registry. 20 or so are in flying condition with the remainder in storage, derelict, on display or under restoration. There are around 5 that are currently being flown on the airshow circuit.

Specifications (A-26B-15-DL Invader)

Crew – 3

Wing area – 540 ft²

Length – 50 ft 0 in

Empty weight – 22,850 lb

Loaded weight – 27,600 lb

Max takeoff weight – 35,000 lb

Wing Span – 70 ft 0 in

Height – 18 ft 3 in

Engines – Pratt & Whitney R-2800-27/79 “Double Wasp”, 2,000 hp

Max speed – 365 mph, 308 knots

Climb rate – 1,250 ft/min

Range -1,400 mi

Wing loading – 51 lb/ft²

Ceiling – 22,000 ft

Power/loading – 0.145 hp/lb


Guns – 6 – 0.50 cal (12.7 mm) M2 Browning machine guns in the nose with 8 – 0.50 cal M2 machine guns in four optional underwing pods. Or 8 – 0.50 in (12.7 mm) M2 Browning machine guns in the nose with 6 – 0.50 cal M2 machine guns in the wing and 2× 0.50 cal M2 machine guns in remote-controlled dorsal turret and 2× 0.50 cal M2 machine guns in remote-controlled ventral turret.

Bombs – 6,000 lbs. 4,000 lb in the bomb bay plus 2,000 lb external on the wings. Later versions also carried rockets under the wings.

Popular culture

Two B-26 airtankers (No. 57 and No. 59) were prominently featured in the 1989 Steven Spielberg film, “Always”. This was a remake of the WWII era Spencer Tracy movie, “A Guy Named Joe”. The flying for the movie was performed by well-known movie pilot Steve Hinton and Denny Lynch, the owner of the A-26s. Steve Hinton continues to this day as an expert warbird and movie pilot and is the President of The Air Museum at Chino California. Denny Lynch retired in Billings Montana and died in 2005. He was a renowned fire bomber pilot and had operated Lynch Air Services in Billings for many years.

Tanker 57 was sold to AirSpray in Red Deer, Canada. They became the largest operator of Invaders as fire bombers. It sits today at the airport but is slowly being stripped for parts. AirSpray has ceased Invader operations and is slowly selling the remaining few aircraft. The Invaders were finally replaced by Lockheed Electras and Canadair CL-215’s.

The star of the show was Tanker 59, “Fire Eater”. It remained at Billings Montana for years but was sold in 2008. It was flown to the Midwest for restoration.