The United States Air Force, of course, included more than bombers in its fleet. Among various highly successful middle and small-size aircraft, two are of a particular interest: North-American's B-25 Mitchell and Martin's B-26 Marauder. This group of highly accomplished medium bombers should also include Douglas's A-20 Havoc ground attack aircraft. To understand how an attack aircraft came to be listed among bombers, it is necessary to understand the attitude of American Air Corps to ground attack aviation as such. With almost no experience of ground operations prior to the summer of 1944, the American military had only a very hazy notion of what ground attack aviation's objectives and tactics are. Successfully employed in the ground attack role at the beginning of the war, the Douglas SBD naval dive-bomber and its land-based version, the A-24 were now outdated. It was necessary to replace them with something new, but aviation leaders had no idea as to what form an attack aircraft should take. As a result, there was no specialized ground troop support aircraft in the American Air Force during the final stages of the war. Most often this role was taken up by P-38, P-40 and P-47 fighters, while the planes specifically designed as ground attack aircraft, including some excellent machines such as Douglas's A-20 Havoc and A-26 Invader, were used as middle-range bombers instead.
Douglas started to work on a completely new middle-range bomber in 1936. The project had been designated “Model 7A,” and the export version was subsequently dubbed “DB-7.” On October 26, 1938, the prototype aircraft made its first flight, and in February, the company received an order from France for 100 machines. By May 1940, when France was attacked by Germany, the French had deployed 60 of the aircraft, 12 of which fought the Germans with good results. Since France was quickly defeated, Britain decided to accept deliveries of the airplanes ordered by France and Belgium. These machines were exported to Britain under the name of “Havoc-I.” Their subsequent success compelled the Americans to consider buying the aircraft for the U.S. military.
The À-20À became the first version of the bomber to be purchased by the United States Air Force. The aircraft resembled the DB-7 but was powered by R-2600-3 engines without turbochargers. To boost production, Douglas licensed the aircraft to Boeing, which made 140 À-20s for the British Royal Air Force under the lend-lease agreement as Boston-IIIA. The DB-7 version of the aircraft was also supplied to the USSR.
The next production version of the aircraft was the A-20G, of which a total of 2850 machines were made. The aircraft was powered by R-2600-23 engines and armed with two 12.7-mm machine guns and four 20-mm cannons in front. The next A-20G modification featured 12.7-mm machine guns in place of the 20-mm cannons, had hard points under its wings for 907-kg bombs, and could carry additional fuel tanks inside its bomb bay as well as an external expendable fuel tank that increased its range to 3000 km. This last feature led to its deployment in the Pacific. In addition, 412 aircraft of the À-20Í version were made. This machine differed in that it was powered by a new R-2600-29 engine rated at 1700 hp. In all, Douglas built 7385 A-20s. Apart from those that did service in the American military, a number were exported to Australia, New Zealand, Great Britain, and the USSR.
Deliveries of production À-20s to the U.S. Air Corps started in the spring of 1941. The first to receive them was the 3rd Bomber Group. A few days before Pearl Harbor, several of the aircraft were taken in by the 58th Air Squadron at Hickam Field Air Base, Hawaii. In the Japanese attack, 10 of these aircraft were destroyed on the ground. In August 1942, the 3rd Bomber Group, made up of A-20s, arrived in Port Moresby, New Guinea. It was there that a very simple and at the same time very effective "gunship" tactic was devised for the A-20s: the aircraft made strafing and low-level bombing attacks against enemy transport convoys. The tactic proved so successful that a separate 15th Air Army made up entirely of A-20s was formed under General Kenyi. It first saw action in New Guinea and later on Palau and in the Philippines. After the capture of Leyte, A-20s were able to make raids against targets as far away as Formosa (Taiwan) and the Chinese coast. In its last action, the À-20 served the 417th Bomber Group in the Battle of Okinawa. Specially equipped A-20s, designated “P-70 Nighthawks” and stationed in New Guinea and on Guadalcanal, were used as night fighters until the arrival of the latest Northrop P-61 Black Widow.
Very small by American standards, the airplane with a crew of only two made an invaluable contribution to the allied victory in the Pacific. A genuine multi-role workhorse, it was used again and again to plug multiple holes in the tactics employed by the U.S. Air Force. A-20 served in every imaginable role: bomber, ground attack aircraft, reconnaissance plane, torpedo bomber, maritime patrol/anti-submarine aircraft, fighter. And in each role and everywhere, it earned the love and respect of pilots because on countless occasions this simple but reliable machine helped its crew to survive in an emergency. By the way, North-American's B-25 Mitchell - the primary American two-engine bomber - was first presented at a competition as a ground troops support aircraft. The A-20 won that competition but both of them earned their fame as medium bombers rather than as ground attack aircraft.
A bomber produced at Martin facilities in Baltimore to replace the B-18 Bolo at the end of 1940 achieved a different sort of fame. This aircraft is commonly spoken of only in terms of its speed, long-range, and high-altitude capability. The pilots, though, called the B-26 Marauder “hubby killer,” “widow maker,” and “Baltimore whore.” Landing with just one inoperative engine guaranteed a crash. Extreme nose-heaviness made the bomber almost uncontrollable at takeoff. Aircraft mechanics would try to compensate by shifting everything on board of any weight into the tail part. Once airborne, the B-26 was totally unpredictable. It is not for nothing that in the end, all remaining operational machines were transferred to the 22nd Air Group with its corps of highly experienced pilots. In July 1941, out of 66 bombers produced, only 21 were flying; the others, though in perfect condition, were tucked away in far corners of airfields - pilots were simply afraid to fly them. It was on April 5, 1942 that the B-26 saw combat action for the first time - against Rabaul. During May and April the 22nd Air Group made 16 raids and by the end of 1942 another 36. The losses were so heavy that in January 1943 all the aircraft in that group were replaced with B-25s. In the middle of 1943, all the “Hubby Killers” in the Pacific were collected in the 19th Air Squadron, which fought in the south-western part of the Pacific until January 1944, when the B-26 was permanently withdrawn from service.
Meanwhile, the enormous success of the A-20 led Douglas to contemplate further improvements to the design so as to retain a competitive edge. In 1940, the company received an order to build three prototypes: the XA-26 ground attack bomber with a bombing operator on board, the XA-26A night fighter, and the XA-26B ground troops support aircraft. After a series of flight tests, the Air Corps ordered production of the A-26B Invader attack aircraft - a direct descendant of the A-20. The aircraft participated in its first fight in November 1944. The A-26 was perhaps the only American dedicated ground attack aircraft to achieve some measure of success in its initially intended role. Armed with 10 to 20 (!) 12.7-mm machine guns and capable of carrying more than 1800 kg of ordnance, the A-26 became by far the best American ground troops support aircraft. In addition, with its 571 km/hr maximum speed, it was also the fastest American bomber for a time.
We should also mention Lockheed's bombers designed just before the war on the basis of the Model 18 Lodestar transport. A total of 3028 B-34 Lexingtons, B-37 (PV-1) Ventura's and PV-2 Harpoons served throughout the war in precisely the roles for which they had been designed - as maritime patrol/anti-sub airplanes or naval strike bombers.
The principal bomber in the Pacific region, however, was none other than the North-American B-25 Mitchell, which took to the air for the first time in January 1939 as the NA-40 prototype. The NA-40 had been entered in the same competition as the Douglas Model 7A, which had won and entered production as the A-20, the Martin XA-22 Maryland, which was later exported in large numbers as an attack aircraft, and the Boeing-Stearman XA-21. Still another competitor, the Bell Model 9, was rejected at the stage of concept study. North-American had lost the competition for the best attack aircraft but there was still a chance to get on board by upgrading their offer and presenting it as a bomber instead. For the next competition the company rolled out a prototype designated NA-62. The other designs taking part were: Martin's Model 179, Douglas' B-23, and Stearman's P-23. However, the competition was won by the Martin B-26 with its perfect aerodynamics. Martin secured a contract for 200 aircraft worth more than $15 million. As a consolation prize, North-American received funds to continue work on their design. On September 10, 1939, the company signed a contract worth more than $11 million to build 184 of their latest B-25 Mitchell bomber. The first production B-25 rose into the air on August 19, 1940, and from February 1941, the 17th Air Group, based in Pearl Harbor, started to accept deliveries of the new bomber.
«Douglas» A-20 «Havoc» -the workhorse of U.S. Air Corps.
«North-American» B-25 «Mitchell» - primary two-engine U.S. bomber.
«Douglas» A-26 «Invader» - the fastest two-engine U.S. bomber.
«Martin» B-26 «Marauder» - a humble failure called «Hubby killer».
The start of its military career was far from glamorous. Having lost most of its aircraft, the 17th Air Group was transferred to the continental Untied States to patrol the West Coast.
In March 1942, 48 B-25G bombers destined for the Dutch East India Air Force arrived in Australia but were assigned to the 3rd Bomber Group instead. The 13th and 90th Air Squadrons together with the 38th Group, which had arrived in August, were operating in the air space over and around New Guinea throughout 1942. B-25s were better adapted to local airfields than capricious Â-26s so that the 22nd Air Group, already mentioned in this account, switched to this bomber as well. Almost at the same time, in June 1943, the 345th Group was reassigned to New Guinea.
The Pacific war theater, unlike that in Europe, was huge, with no clearly defined frontline and no well-organized air defenses so that Â-25s for the most part were used in hunting for enemy ships and in operations against air bases in and around Rabaul. In March 1943, B-25s scored a big win in a fight with a large Japanese transport convoy in the Bismarck Sea. Having suppressed the enemy air defenses with machine gun fire, the aircraft continued with bombing from low altitude. In their second attack, they sunk a destroyer and damaged another one together with two transport ships. American and Australian pilots pounded the convoy for three days, effectively preventing the Japanese invasion of Lae.
Â-25s were also actively used in Burma and China. Their main targets there were Japanese overland supply routes, especially a single-track railway from Rangoon, which numbered more than 100 bridges. After a series of failed attempts, the Americans managed to destroy 8 of them.
Â-25Ís also supported the Allied offensive in Burma in 1944. In the summer of 1944, the aircraft was used to mine Chindwin river. By July 1944, the number of Â-25s in this region rose to 345. B-25Gs and Â-25Ís supported Allied invasions of the Marshall and Caroline Islands as well as the Bismarck Islands. Â-25s also flew against the Japanese from Alaska.
But the best known coup of the Mitchells was the famous Tokyo air raid made on April 18, 1942 by 16 B-25B bombers under the command of Lieutenant Colonel Doolittle. On April 2, 1942, a Hornet aircraft carrier, accompanied by a group of warships, left San-Francisco and crossed the Pacific. To avoid detection by the Japanese, the bombers took off hundreds of kilometers from their intended target. All the B-25s taking part were irretrievably lost to the Americans. Out of 80 crewmen, three died, seven were injured and eight taken prisoner. The rest managed to return home. Doolittle was promoted to the rank of general, and American morale, which had plunged after Pearl Harbor, began to rise.
The Â-25 and Â-26 may serve as an illustration of the main trends in the development of American medium bombers: better crew and aircraft protection, reduced pilot workload and simpler maintenance, improved pilot's view and crew comfort. As a matter of fact, all these improvements were achieved at the expense of aircraft flight performance. However, given the overwhelming American air dominance, this turned out to be a less important consideration.
Suvorov Andrey Sergeevich, 2004, St. Petersburg
References:
Everett Cassagneres. Boeing B-17 E/F Flying Fortress. Aircraft Profiles ¹77.
Roger A. Freeman. Boeing B-17G Flying Fortress. Aircraft Profiles ¹205.
Mitch Mayborn. Boeing B-29 Superfortress. Aircraft Profiles ¹101.
Roger A. Freeman. Consolidated B-24J Liberator. Aircraft Profiles ¹19.
Ray Wagner. Martin B-26B&C Marauder. Aircraft Profiles ¹112. 1969.
North American B-25J Mitchell walk-around by Paolo Pizzi.
Naval Aircraft PBJ-1 Mitchell by Harold Andrews.
Ernest R. McDowell. B-25 Mitchell in Action. Squadron Signal publications ¹34.
Lou Drendell. Wolk Around B-25 Mitchell. Squadron Signal publications ¹12.
Willy Peeters. Boeing B-17 Flying Fortress. Lock On Aircraft Photo File ¹24.
Larry Davis. B-17 in Action. Squadron Signal publications ¹63.
Jacek Nowicki. B-29 Superfortress. AJ-Press. Monografie Lotnicze ¹13.
Larry Davis. B-24 Liberator in Action. Squadron Signal publications ¹80.
