B-26K

Background

During the mid-1950s, B-26-equipped USAF wings began to be re-equipped with jet-powered Martin B-57 and Douglas B-66 aircraft, and the Invaders were removed from front-line service. However, during the 1960s the 1st Air Commando Wing at Eglin AFB in Florida continued to use B-26s in order to develop counter-insurgency techniques and tactics. In addition, some B-26s were operating clandestinely in South Vietnam, supposedly serving with the South Vietnamese air force, but actually flown by American aircrews.

Unfortunately, these B-26s began to suffer frequent wing failures, forcing them out of service. Those that remained were provided with a strengthening wing strap along the bottom of the wing spars to prolong service life. The success of these modifications led the USAF to order a remanufactured version of the Invader from the On Mark Engineering Company of Van Nuys, California that would be specifically adapted to the counterinsurgency role. The On Mark company had not previously built any military aircraft, but they had been extensively involved in conversions of Invaders for civilian use. The designation B-26K was applied and the name Counter Invader was chosen.

Development

The Counter Invader was powered by a pair of 2500 hp Pratt & Whitney R-2800-103W water-injected engines driving a set of fully-reversible automatic feathering propellers. The wings were entirely rebuilt and strengthened by the installation of steel straps on the top and bottom of the spars. The rudder was enlarged to improve single-engine handling. Permanent 165 US gallon wingtip fuel tanks were installed. An anti-skid wheel braking system was adopted. Deicer boots and anti-icing equipment was added. The instrument panel was revised and provision for dual controls was made. New electronic equipment was adopted. Eight new underwing pylons were added for a variety of external stores. The dorsal and ventral defensive turrets were eliminated, and fixed armament consisted of a set of eight 0.50-inch forward-firing machine guns in the nose. Alternatively, the aircraft could be fitted with a glazed nose for photographic reconnaissance.

The first modified Counter Invader was built from RB-26C 44-35634. It had been converted into a B-26B in August of 1961 and employed as a squadron "hack". This aircraft was transferred to On Mark in October of 1962. When the work was completed, the aircraft was redesignated YB-26K. Contrary to some published sources, it was NOT assigned the new serial number 63-5634--the number 35634 painted on the aircraft were simply the last 5 digits of its original serial number. It flew for the first time on January 28, 1963. It was delivered to the 1st Air Commando Wing at Hurlburt for evaluation in June of 1963.

Following the completion of test flights, the USAF ordered 40 B-26Ks modified to similar standards. Most of the aircraft selected for conversion were B-26Bs or TB-26Bs, with just two B-26Cs and a single JB-26C. They were assigned the new serial numbers 64-17640 through 64-17679. The B-26Ks differed from the YB-26K primarily in having 2500hp R-2800-52W engines in place of the R-2800-103Ws. The propeller spinners were omitted and the six wing guns were deleted. The B-26K could carry 4000 pounds of bombs internally, plus up to 8000 pounds on the underwing racks. Besides the fixed wingtip tanks, two 230-gallon drop tanks or a 675-gallon bay tank could be carried. These changes increased the maximum cruising speed from 240 to 265 knots, the combat radius from 210 to 500 nautical miles, and increased the armament load from 7500 to 12,000 pounds. There were significant improvements in rate of climb and service ceiling. However, the aircraft was somewhat less stable than the original B-26 and it was no longer possible to trim it for hands-off flight.

All B-26Ks were fitted with an eight-gun solid nose, but this could be replaced by a glazed B-26C-type nose in about four hours. The B-26K could be readily converted into a RB-26K reconnaissance aircraft by the installation of a glazed nose and a removable bomb bay system of four cameras and flash ejectors.

Operational History

The first non-prototype B-26K flew on May 26, 1964. The B-26Ks were delivered to the USAF between June 1964 and April 1965. They had originally been intended to replace the ageing B-26s operating in Vietnam with Farm Gate. However, these B-26s had been taken out of service prematurely due to wing spar fatigue, and had been replaced by A-1 Skyraiders. Consequently, the B-26K was no longer urgently needed in Southeast Asia, and most the planes were kept in the USA for the time being. They officially entered service with the 602nd Fighter Squadron (Composite) at Hurlburt AFB. The squadron was later renamed the 6th Fighter Squadron (Composite). The last seven were allocated to the 605th Air Commando Squadron at Howard AFB and Albrook AFB in the Panama Canal Zone. The original paint scheme for the B-26K Invaders was a gloss green upper half and a gloss white lower half. A few of the planes at Albrook AFB were also tested out using a blue-grey all-over gloss paint scheme.

Anstalt Wigmo

Unofficially, the B-26K saw combat almost immediately after being introduced. Five planes were lent to the CIA to support a clandestine operation in the Congo called Anstalt Wigmo. These planes were flown by volunteer Invader pilots from Latin American countries that had some experience with flying Invaders in combat and in CIA operations. The first three Invaders assigned to this operation, 64-17644, 64-17645, and 64-17646 arrived in the Congo 18 Aug 1964. In September, they were joined by a regular B-26B (44-35890) from CIA inventory, and the last two K models to arrive, 64-17649 and 64-17662, showed up in January 1965. In addition to providing some important real-world combat testing of the new K-model, this operation also allowed air crews in the field to overcome a technical issue. The original modifications from On Mark did not include any changes to the engine cowling, but they did put larger engines in the air frame. During wartime operations in the tropics this caused the engines to overheat. The crews operating the Invaders in the Congo solved this problem by moving the air intake higher up the cowling and enlarging the vent. This "Congo Cowling", as it became known, was eventually adopted as a standard modification on the K models and helped keep them running later in the jungles of southeast Asia. These Congo planes were painted in the same green and white gloss scheme as the American planes, but they lacked any American identifying marks at all. Even their serial numbers were abbreviated and shortened.

Official Missions

The rest of the B-26Ks not in a secret op in the Congo spent the first couple of years of their service on training units in the USA and in Central America. In mid-December of 1965, the B-26 training program moved from Hurlburt AFB to England AFB, Louisiana and the Invader unit changed its name to the 603rd Fighter Squadron, which was subsequently renamed the 603rd Air Commando Squadron.

Operation Steel Tiger

In the spring of 1966, it was decided to deploy B-26Ks to Southeast Asia in an attempt to stem the flow of war material down the Ho Chi Minh trail from North Vietnam via Laos. Since northeastern Thailand was much closer to the intended area of operations in southern Laos, the US Government obtained permission for the Invaders to be stationed there rather than in South Vietnam. However, during the mid-1960s, Thailand did not permit the basing of bombers on its territory, and so in May 1966 the aircraft were reassigned the old attack designation of A-26A, thus bringing the Invader full-circle. Some people mistakenly call this renamed plane the A-26K, but this is not correct as there was never an A-26K. When The B-26K was renamed as an Assault class it took A-26A because the A slot had never been officially used; the XA-26A was not accepted for production.

The A-26As deployed to Southeast Asia were attached to the 606th Air Commando Squadron, based at Nakhon Phanom Air Base (NKP) in Thailand. The mission of the 606th was known as Lucky Tiger. The A-26A unit was officially known as Detachment 1 of the 603rd Air Commando Squadron on six months' temporary duty in Thailand. The operations of the A-26As over Laos were considered black ops, clandestine operations and the national insignia were painted out in order to maintain some sort of plausible deniability if something went wrong and one of them were forced down. These early missions also required a Vietnamese Observer who rode in the now-vacant gunners compartment. Initially they were supposed to authorize targets, and fairly quickly they were just along for the ride. After a time the pretense was dropped altogether and they were no longer required. The area of the Laotian panhandle along the North Vietnamese border became known as Steel Tiger, and it became the primary target of the A-26As. By the time the A-26As arrived at NKP Air Base they were painted in a traditional jungle 3-color camo.

Most of the A-26A combat missions over Laos were interdiction missions flown at night, the North Vietnamese antiaircraft defenses that were installed along the Ho Chi Minh Trail making it too dangerous to fly slow-moving aircraft such as the piston-engined A-26A over the area during the day. The primary targets were truck traffic along the Trail. Sometimes the A-26As were equipped with AN/PVS2 Starlight scopes for enhanced nighttime visibility. Most of the time they were equipped with solid noses, but a few missions were flown with glass noses. By December 1966, the A-26As had claimed a total of 99 trunks destroyed or damaged. At the end of December, the aircraft were reassigned to the 634th Combat Support Group at Nakhon Phanom. In April of 1967, the A-26As were officially transferred over to the 609th Air Commando Squadron, which was part of the newly-formed 56th Air Commando Wing.

The A-26A could carry a maximum of 8000 pounds underneath the wings plus 4000 pounds internally. However, the actual load carried on combat missions was usually somewhat less in order to gain maneuverability and to reduce stress loads. A typical underwing load was a pair of SUU-025 flare dispensers, two LAU-3A rocket pods, and four CBU-14 cluster bomb units. Later, the rockets and flares were often replaced by 500 lb BLU-23 or 750 lb BLU-37 finned napalm bombs. The M31 and M32 incendiary clusters could also be carried, as well as M34 and M35 incendiary bombs, M1A4 fragmentation clusters, M47 white phosphorus bombs, and CBU-24, -25, -29, and -49 cluster bomb units. General-purpose bombs such as the 250-lb MK-81, the 500-lb MK-82, and 750-lb M117 could also be carried.

In the summer of 1968, all Air Commando Wings were re-designated as Special Operations Units, and the 56th ACW became the 56th Special Operations Wing, with the 609th ACS becoming the 609th Special Operations Squadron.

Retirement

The night interdiction tasks of the A-26A were gradually taken over by AC-130A and AC-130E gunships, and the Counter Invaders were phased out of active service by November of 1969. The losses had been fairly heavy, with no less than twelve out of the 30 that had served in Thailand at one time or another having been lost to enemy action. The 609th SOS was awarded the Presidential Unit Citation for extraordinary gallantry.

Following their withdrawal from service, most of the A-26As were immediately transferred to storage with the MASDC at Davis-Monthan. Five were handed over to the South Vietnam air force for use as instructional airframes (64-17641, 64-17644, 64-17652, 64-17654, & 64-17677). These were blown up at Nha Trang in March of 1975 as the North Vietnamese army was about to overwhelm the South.

Ten were held in readiness just in case they might be needed again and it was not until February 1973 that the last A-26A was consigned to storage. Five of them ended up in museums in the USA and South Korea.

See a complete list of all of the B-26K/A-26A planes here: Serial Numbers starting with 64 or browse the specific planes from the links below.

List of Planes

USAF S/N	Converted from	Status	End date	Comments
64-17640	44·35896	On Display	Present	Purchased by State of Georgia Forestry Commission (N267G), sold to Air Spray, Ltd, Owned by Arthur W. McDonnell (N2294B), acquired by USAF Museum
64-17641	44-35322	Shot down	29 Dec 1967	Cpt Cruz, Cpt Potter, A1C Foster - all KIA
64-17642	44-35435	Lost in action	27 Aug 1967	Lt.Col Jensen, Maj Smiley - both MIA, later KIA
64-17643	44-35392	Destroyed in crash landing at NKP	24 Jul 1966	Maj Duke, Cpt Tanimoto - both KIA
64-17644	44-35451
64-17645 44-35546 Steel Tiger; to South Vietnam	65-17646 44-35375 Steel Tl[er; lo;t 7/69	[[64-17647 44-35904 scrapped 12L72	[[64-17648 43-22732 Steel T'!i.er; lost 5/68	[[64-17649 43-22720 Steel Tiger; scrapped 12/72	[[64-17650 44-35766 Steel T~er; lost 6/66	[[64-17651 44-34119 Steel Tiger; LO display in Korean museum	[[64-17652 44-34361 Steel Tiger; LO South Vietnam	[[64-17653 44-39378 Steel Tiger; to display in Pima Air Museum, AZ	[[64-17654 44-39491 Steel Ti.!!.er; [Q South Vietnam	[[64-17655 44-34184 scra pped 12/72	[[64-17656 44-35847 accident 12/64 -	[[64-17657 43-22649 to N62104, N99218	[[64-17658 44-35685 scrapped 12/72	[[64-17659 41-39564 accident 8/65	[[64-17660 44-35608 Steel Tiger; scrapped 12/72	[[64-17661 44-35433 Steel Tigeriscrapped 12172	[[64-17662 44-35458? or 4]·394621,;Steel U,/lerilost8/67	[[64-17663 41-39462 or 44-35458? Accidel1l 4/65	[[64-17664 43-22665 Steel Tiger; scrapped 12/72	[[64-17665 44-34145 Steel Tiger; scrapped 12/72	[[64-17666 44-35483 Steel Tiger; to display at Hurlburt Field, FL	[[64-17667 44-35468 Steel Tiger;. lost 3/69	[[64-17668 44-34652 Steel Tiger; lost 2/67	[[64-17669 44-34606 Steel Tiger; lost 2/67	64-17670 44-35634 (rom YB.26K; Steel Tiger; scrapped 2/72	64-17671 44-35820 Steel Tiger; [Q display at Florence, SC museum	64-17672 44-35251 Steel Tiger; lost 12/66	[[64-17673 44-34135 Steel T'!i.er;. lost 3/69	[[64-17674 41-39573 accidel1l 1/69	[[64-17675 44-34173 Steel Tiger; scrapped 12/72	[[64-17676 41-39596 Steel Tiger; LO N268G, C·GXTF, N22939, to display in USAF Museum, Dayton, 011	64-17677 44-34108 or 44·35205?; Steel T~.er; to Sourh Vietnam	64-17678 44-35205 Or 44·34108?; Steel Tiger; scrapp	64-17679

Disposal of Planes

Many of the secondary sources have several airframes listed as scrapped in December 1972. These planes were at the Davis-Monthan AFB storage yard when the planes were declared excess on 15 Dec 1972 and were authorized to be scrapped. However, in examining the records at Davis-Monthan it reveals that 9 planes were sold to Allied Aircraft, Inc of Tucson, AZ between March and May 1976 and a 10th plane was sold to them in 1980. There is no record of what became of these planes, but based on the details surrounding 64-17660 I can only assume that Allied scrapped them after acquiring them.