The Martin B-10 is considered to be the first “modern” military bomber. At the time it was introduced, the design, featuring retractable landing gear, turreted defensive machine guns, and an internal bomb bay, was considered revolutionary. Not only could it carry a full ton of bombs, but it was fast enough to outrun almost all existing fighter planes. On the eve of the Second World War, the B-10 changed the entire face of air combat.
In 1931, the US Army Air Force was looking for a new heavy bomber, to fight a new kind of war.
At the beginning of the First World War in 1914, “aerial bombing” consisted of slow ponderous biplanes, in which an observer could manually toss grenades or small finned bombs out over the side of the plane onto enemy trenches. But the technology advanced rapidly, and four years later when the war ended, German Gotha and British Vickers long-range bombers were carrying out strategic attacks on each other’s cities.
This new capability inspired a completely new way of looking at war. With strategic bombing, some military theorists concluded, it was now possible to avoid the long drawn-out bloody trench battles of the Western Front and defeat an enemy solely through air power, using heavy long-range bombing raids to destroy his industry, terrorize and demoralize his population, and make it incapable for the enemy to continue to fight.
But this could not be done with the slow vulnerable canvas-covered biplanes from the First World War. It required new technology–which came in 1931.
The Martin bomber didn’t start out as a revolution. The original design for the B-10 was fairly conventional: its major innovation was that it was a newer monoplane instead of the traditional biplane, and was built entirely of metal skin instead of a canvass-covered frame. The bomb load was carried on standard racks located under the wings. But the design produced too much drag, leading to slow speed and poor performance. To decrease the drag, engineers decided to remove the bomb racks from the wings and place them inside the fuselage instead. That made all the difference.
That change in turn led to a cascade of other improvements. An internal bomb rack required a larger and roomier fuselage. This allowed enough internal space for retractable landing gear in which the wheels folded up inside the plane after takeoff, greatly increasing the speed. The bigger fuselage required a larger wing for more lift, which in turn allowed for more powerful engines. So not only could the plane now carry a bigger and heavier bomb load–a then-incredible 2,000 pounds of bombs–but it could carry the extra weight of three defensive .30-caliber machine guns including a rotating turret, giving it unmatched defensive firepower. And, with its powerful engines, the streamlined bomber could fly at over 200mph, faster than nearly any existing fighter plane.
In one stroke, the Martin B-10 made every other bomber in the world–and most fighter planes–obsolete. Though given the unglamorous nickname of “The Whale” (because of its bloated belly), it was the dream plane that every strategic air war theorist had wanted. Vast formations of such bombers could, the reasoning now went, fly long distances to pummel any opponent’s industrial cities into ruins, outrunning enemy fighters and using its bristling machine guns to fight off any interceptors that were able to catch the bombers. It led to a slogan that summed up the new military outlook: “The bomber will always get through.”
In 1934, the United States undertook a project which showed off the full potential of its premiere new bomber. Led by Lt Col Henry “Hap” Arnold, a group of 10 B-10s took off from Washington DC. Over the next week, the aircraft flew all the way to Alaska, then made a series of long-range flights over the Arctic. Officially, the purpose of the mission was to photograph the northern regions and to map new flight paths to Asia and Europe. Unofficially, it was a show of power directed at what were already potential US enemies in Japan and Germany.
In 1935, the capabilities of the B-10 were improved when it was used to test the new Norden bombsight, which was intended to allow pinpoint-accurate bombing of enemy industrial and war-production targets.
By the time the Second World War broke out, however, the B-10 was the victim of its own success. Shaken by the revolutionary new design, other nations were forced to quickly find a way to meet the threat. By 1939, a new generation of fighter planes was in the works–fast heavily-armed all-metal monowings like the German Messerschmitt, the Japanese Zero, and the British Spitfire–all designed to take on bombers like the B-10. In the strategic bombing role, meanwhile, the B-10 was surpassed by larger, faster, more heavily-armed planes like the Lancaster and the B-17.
The B-10 did play a peripheral role during the early part of World War II. Export versions had been sold to China, where they served during the war against Japan. The first air raid on Tokyo was carried out by two Chinese B-10s–though they dropped propaganda leaflets instead of bombs. A number of B-10s were also sold to the Netherlands, where they fought against the Japanese in the East Indies from 1941 to 1942.
In all, the US produced 348 B-10 bombers, selling 182 of these overseas. Today, only one still remains. Originally part of a group of 40 sold to Argentina in 1938 and used for coastal patrol, this sole survivor was still being used as a training aircraft for ground crews in the 1960’s. In 1970, it was donated by the Argentine Government to the US Air Force Museum, which restored it in the markings used by the 1934 Alaska Expedition. It is now on display at the Museum.