N.B. The B-26 Invader is not to be confused with the B-26 Marauder. After the Marauder was retired from service in June 1948, the A-26 Invader was redesignated B-26. The attack designation was dropped in 1947, and the attack mission was absorbed by other aircraft classes, primarily fighters and bombers, only to be revived during the Vietnam War. Confusion over the distinction between the two aircraft persists today. While both are twin engine aircraft using the same Pratt & Whitney R-2800-5 Double Wasp radial engines and having a roughly 70 foot wingspan, they are otherwise un-related and dis-similar aircraft. The Invader fuselage is shorter with a lean and hungry look, while the Marauder's fuselage is decidedly husky and muscular, if not quite plump.
Despite its designation, the A-26 (Invader), which first appeared in combat in 1944, was the most advanced medium bomber used by the AAF during the war. Douglas began designing the plane in January 1941, building the new model on the best features of the DB-7 and the A-20 but with plans for a much greater range and bomb load. Flown first in July 1942, the A-26 went into production in September 1943. By May 1945 six A-26 groups had been committed in overseas theaters. Acceptances of the plane reached almost 2,500 by August 1945.
The Invader was an all-metal midwing monoplane powered by two Pratt & Whitney R-2800 engines, the same power plant used in the un-related B-26. With a combat weight of 35,000 pounds, the A-26 could fly at 360 miles per hour, more than 60 miles faster than the other medium bombers. Its combat range reached i,ooo miles, with a bomb load of 4,000 pounds and a three-man crew. Formi- dably armed with eighteen .50-caliber machine guns and fourteen 5 -inch rockets, the plane had a maximum bomb load of 6,000 pounds, two-thirds of it carried intemally.
As early as 1942 the AAF planned to replace all other mediums with the A-26. But production delays, for which AAF Headquarters was inclined to blame the Douglas Company, kept acceptances to a total of only twenty-one planes by 01 March 1944. Arnold's insistence that he wanted the plane "for use in this war and not for the next war" helped to overcome certain shortages of machine tools, and after July 1944 production mounted steadily. Though a late comer, the A-26 compiled a distinguished combat record and, after a period of uncertainty in 1944, won ready acceptance from the crews who flew it. In the postwar period, the A-26 became the Air Force's standard tactical bomber.
Development of the B-26 Invader, initially known as the A-26, originated in November 1940, when the Army Air Corps's Experimental Engineering Section at Wright Field, Ohio, gave first priority to the Douglas Airplane Company for designing and developing a new plane. But, as evidenced by official requirements, the so called new design drew a great deal from the A-20 Havoc. The A-20 was a Douglas production, developed in 1937 from Model A-7: a 1936 original design for a high performance attack bomber.
Official Army requirements, as spelled out by the Air Corps, called for a new plane that would be faster and structurally stronger than the A-20. Additional defensive armament over the A-20 and shorter takeoff and landing distances, were also part of the requirements. The Air Corps wanted the new plane eventually to replace the A-20, the Martin B-26 Marauder, and the North American B-25 Mitchell.
The first of the 3 XA-26s, ordered in the summer of 1941, was not initially flown until 10 July 1942. The other 2 experimental planes were flown on the heels of the first one.
Testing of the 3 XA-26s, as well as the experience already gained from combat in Europe and the Pacific area, prompted the Army Air Forces to decide that the 500 aircraft, covered by the production contract of June 1941, would be patterned on the third experimental plane: the XB-26B ground attack configuration that featured a 75-mm cannon nose, primarily intended to destroy tanks. In short, a heretofore uncertain Army Air Forces gave priority to ground attack over the multi-purpose light bomber requirements of 1940. Yet, the aircraft's versatility was not overlooked. Two hundred additional noses, each with six .50 caliber guns, would also be procured. Each of the latter noses could be installed in about 24 hours by field personnel.
Delay of the XA-26's first flight clearly indicated that, at best, mass production would not begin before July 1943, a significant slippage from the original time estimate. Lack of tooling was a primary factor, but shortages of engineers were equally damaging. Hence, the Wright Field Production Division directed Douglas to transfer at least two thirds of the personnel listed on the C 742 project to the A-26. Also, no engineers were to be utilized for the improvement of crew comfort, or any other endeavors, unless specifically authorized by Wright Field. Finally, no other armament studies were to be made until the A-26 production's stage was more advanced. In January 1943, despite these stringent directives, Douglas informed the Army Air Forces that the new production schedule would not be met. The contractor indicated that October appeared to be a more likely date for production to begin.
In March 1944, when only 21 A-26s had been delivered, General Arnold bluntly expressed his increasing dissatisfaction. "One thing is sure;" said General Arnold, "I want the A-26s for use in this war and not the next war." Maj. Gen. Oliver P Echols, Assistant Chief of Air Staff for Materiel, Maintenance, and Distribution, blamed the continuing delays on Douglas's apparent lack of interest or "little desire to manufacture the plane;' and explained that the Materiel Command all along had urged the contractor to place orders for tools and to find qualified subcontractors. In defense of Douglas, the Western Procurement District, Los Angeles, California, stressed that the A-26 wing was entirely different from that of any other airplane; that delivery schedules were set before design and tooling problems were solved; and that there had been on occasions as many as 35 change orders a day on the A-26.
Existing production problems were not allowed to affect the programmed procurement of additional A-26s. On 29 March 1944, the Under Secretary of War approved 2 supplemental agreements to the production contracts already in force. The extra A-26s, 2,700 of them, were expected to cost about $300 million.
The A-26 had a 70 foot wing span, compared to the 61 foot span of the 30-percent-lighter A-20. Greater care had been applied to simplify the manufacturing and maintenance of the A-26 structure. Moreover, the fuselage of the all metal, semi monocoque A-26 allowed the 3 crewmen to exchange positions, an advantage the A-20 did not offer.
A most unusual feature of the A-26 was the aluminum alloy monocoque engine mount, which was a combination of structure and cowling, thereby reducing weight and easing engine installation. Another special feature was the Douglas devised slotted wing flap, which had a lower pitching movement for a given lift coefficient than the Fowler flap. Finally, the engines were cooled with a new type of high entrance velocity cowling. This cowl induced less aerodynamic resistance and lowered the temperatures of the engines.
The A-26 entered combat testing in mid 1944, when 4 of the aircraft assigned to the Fifth Air Force began operating in the Southwest Pacific. Lt. Gen. George C. Kenney, Commanding General of the Far East Air Forces, grounded the planes after less than 175 hours of total flying time and stated shortly afterwards, "We do not want the A-26 under any circumstances as a replacement for anything." Ironically, about 4 years before, as a colonel in charge of the Wright Field Production Division and a strong proponent of attack aviation, Kenney had strongly urged the aircraft's development. General Kenney's statement and his mid 1944 decision to ground the planes appeared justified. A-26 production had slipped badly; the B-25s and A-20s that the A-26s would replace had proven satisfactory; and the canopy of available A-26s was poorly designed. A new canopy was needed to improve visibility. Without it, pilots could not safely fly the formations required for low level tactics. While the Wright Field Production Division agreed that the A-26 could not replace current types of light and medium bombers, Maj. Gen. Hoyt S. Vandenberg, Commanding General of the Ninth Air Force, was much less critical than General Kenney. The few A-26s introduced in the European theater towards the end of the summer were performing well. Undoubtedly, the aircraft's marginal visibility needed attention. But new productions were seldom free of problems, and General Vandenberg thought the A-26 was a satisfactory replacement for the B-26s and A-20s in Europe.
Regardless of the mixed reports generated by the performance of the early A-26 (A-26As or A-26Bs), the Army Air Forces' plans to re-equip all B-25, B-26, and A-20 units with A-26s were reaffirmed in November 1944. In December, 2 more contracts were approved, and in April 1945 both of the new agreements were supplemented, bringing to 4,000 the total of new A-26s ordered since mid 1944. However, the German surrender on 8 May 1945 prompted a re evaluation of military requirements. Production which had been scheduled to increase to 400 A-26s per month was cut to 150. The procurement orders of 1944 and 1945 were canceled.
Douglas adopted several long standing suggestions by General Arnold: engineering personnel at Long Beach established closer liaison with the Tulsa plant; extra well qualified personnel were placed in the 2 plants; and the number of stations in the production lines was raised. These production changes facilitated modifications of the aircraft, which were designed to improve its effectiveness. An all purpose gun nose was devised and the faulty nose landing gear redesigned. A-26s (redesignated as A-26Cs) that came off the production lines after January 1945 featured an enlarged, raised canopy which provided increased visibility.
The Ninth Bombardment Division was first in pointing out that once pilots were familiar with the A-26, they liked it better than any other plane they had flown. Even General Kenney eventually agreed that improved A-26s particularly the A-26 with the 8 gun nose were proving to be highly satisfactory replacements for the A-20s and B-25s. Deficiencies such as canopy frosting, faulty brakes, and the like were still being corrected. However, substantial progress was achieved swiftly.
The A-26 production was completed in 1945, but the last aircraft was delivered in early 1946.
The Army Air Forces accepted a grand total of 2,451 A-26s. More than 4,000 A-26s, ordered before the end of World War 11, were canceled. The first 9 of the 2,451 produced by Douglas were built in El Segundo, California. The remainder, consisting of A-26Bs and A-26Cs, was manufactured in Long Beach and Tulsa. The Tulsa plant produced 1,086 of the 1,091 A-26Cs.
In June 1948, after the Martin B-26 Marauder was withdrawn from service, the Douglas A-26 dropped its prefix ("A" for attack) and became the B-26, a designation more representative of its actual role as a standard light bomber for the new United States Air Force and the Tactical Air Command in particular.
The outbreak of the Korean conflict on 25 June 1950 catapulted the Douglas B-26 back into combat. Initial targets, selected to prevent reinforcement of the enemy forces, included North Korean troop concentrations, tanks, guns, supply elements, railway yards and bridges south of the 38th parallel. Immediate results were disappointing because bad weather and darkness curtailed the B-26's effectiveness. Engine failures and various mechanical deficiencies were additional handicaps. Moreover, as the war continued, other problems became obvious.
The World War II B-26 was limited in radius of fire and its speed could no longer cope with the air and ground fire of the enemy's modern equipment. The B-26 had no electronic countermeasures capability and could not carry many types of new armament and control and guidance systems.
Almost from the very beginning of hostilities, the Far East Air Forces gained air superiority against an enemy offering little or no daylight air opposition to strategic or tactical operations. But the night hours presented a different situation. Commanders were forced to utilize a part of their available day force for night operations, and the 3d Bombardment Wing's B-26s, more readily usable for night duty, acquired new importance.
Refurbished B-26s sustained significant losses during the war as their tasks increased. Yet, despite their limitations, the obsolete B-26s compiled a distinguished combat record. The first combat strike into North Korea was flown in 1950 by a B-26 crew. On the evening of 26 July 1953, 1 day before the Korean armistice agreement was signed, a B-26 dropped the last Air Force bombs of the Korean conflict in a ground radar directed close support mission.
The B-26's ineffectiveness in Korea, especially during night attacks directed by radar, prompted special modifications. In 1952, the Air Staff decided that several B-26s of the Tactical Air Command would be fitted with more sophisticated electronic equipment. In 1953, some B-26s, already brought up to the reconnaissance configuration, were given additional components to perform electronic reconnaissance and weather reconnaissance missions. Nevertheless, the usefulness of the outmoded B-26 was declining. Too many configurations 16 different ones in the United States, and about 14 in the Far East and Europe had created supply and maintenance problems of terrific proportions. In mid-1953 the Air Staff approved a last modification to attempt standardizing most B-26s into a few basic configurations.
With the advent of the Martin B-57, B-26s began leaving the Air Force's active inventory in late 1954. The last of the B-26s were withdrawn from service in Air Force Reserve and Air National Guard units in 1958.
President John F. Kennedy's policy that the major task of U.S. advisors in Southeast Asia was to prepare the Republic of Vietnam Armed Forces for combat raised the tempo of training and resulted in the delivery of additional equipment to the South Vietnamese. Fixed wing aircraft were in short supply, so B-26s were taken out of storage and modified for special combat missions in Southeast Asia.
Reactivated B-26s began reaching South Vietnam in the fall of 1961. Once in the theater, they accomplished a variety of tasks ranging from standard bombing operations and close air support attacks to visual and photo reconnaissance missions. In mid 1962, the B-26's role in the conflict was further expanded. Several of the aircraft, already equipped for reconnaissance, received additional modifications in order to perform night photo operations and some intelligence gathering duties.
Keeping the weary B/RB-26s flying was a challenge. Despite changes and improvements, the aircraft actually belonged to a type that had been declared obsolete during the Korean War, 10 years earlier. The combination of old age, hard usage, and the operating conditions of Southeast Asia made maintenance of the B-26 force increasingly difficult. The aircraft were becoming more vulnerable to enemy ground fire, and most B/RB-26s were subject to flight restrictions to avoid undue wing stress. Just the same, losses occurred that were directly attributable to structural fatigue. In August 1963, a B-26 crashed after 1 of its wings broke off. Then, a B-26 wing failed during a combat flight in February 1964. All B/RB-26s were immediately grounded and withdrawn from Southeast Asia soon afterwards. Yet, this action did not end the aircraft's war involvement.
Forty B-26s returned to the war zone in mid 1966 as B-26Ks. The modifications for the K model, accomplished by the On Mark Engineering Company, Van Nuys, California, were extensive. The $16 million On Mark contract, initiated in 1962, involved much more than a facelifting of the old aircraft nearly a complete transformation. The B-26K differed from the basic aircraft in that both turrets had been removed; R-2800 52W engines replaced the B-26's R-2800 79s; the wings had been reinforced by the addition of steel straps both on the top and bottom of the spars; the propellers, wheels, brakes, and rudder had been changed; permanent wing tip tanks had been added; instrument panel and electronics were new; 8 wing pylons had been included; and a myriad of minor changes incorporated.
In short, the B-26K was a tactical bomber for special environments, mounted with rocket pods, guns pods, or bomblet dispensers, and capable of being readily fitted with photographic reconnaissance components and other sensors. The B-26K was redesignated A-26A soon after it reached the war theater. The rejuvenated aircraft promptly proved to be an effective hunter and destroyer of trucks and other vehicles, its loitering capability enabling it to locate and attack an enemy often concealed by jungle or weather. Most A-26As stayed in Southeast Asia for nearly 3 years, the last combat mission being flown in November 1969.
In 1970, regardless of designations, none of the old B-26s remained in the Air Force's active inventory; and none remained with the Air National Guard after 1972.
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