Icons of Aviation History: The Martin MB-2 Bomber

The Martin MB-2 was the first American-built bomber to be mass-produced. It is most famous as the airplane that was used in General Billy Mitchell’s bombing tests against battleships.

Martin MB-2 bomber

During the First World War, the US had virtually no capacity to produce military aircraft. Other than the Jenny trainer and some American-made copies of the British DH-4, the fledgling US Air Service was equipped with a handful of Handley-Paige and Caproni bombers from England and Italy.

In 1918, as the war was ending, the Army put out a design requirement for a long-range bomber. One of the responses was the MB-1, designed by Glenn Martin. Martin built a prototype and flew it, unscheduled, to an Army airfield in Dayton OH in September, where he was promptly arrested by military police who thought he was a German. Once it was all straightened out, the Army tested the MB-1, liked it, and ordered production, but none reached the front before the war ended two months later.

By 1920, Martin had redesigned his bomber, with the express purpose of giving it the biggest possible bomb load. Now designated the MB-2, it featured two engine nacelles with V-12 Liberty engines. Although slower than the MB-1, it could carry a larger load of 2,000 pounds of bombs, with a range of about 500 miles. Five Lewis machine guns provided defense against enemy fighters. A new innovation introduced with the MB-2 was folding wings: since the bomber was so big, it would not fit into standard airplane hangars, so a hinge was added to each wing, just outside the engine nacelle, that allowed them to be folded backwards. The concept was quickly adapted for Navy carrier planes.

The Army approved Martin’s new design to replace the MB-1, and assigned it to night-bombing, under the designation NBS-1. Over the next few years, about 110 MB-2’s were built. Martin made the first production batch, and after that three other companies were given contracts to produce the design. Eight squadrons of MB-2’s were deployed in the US, Hawaii, and the Philippines, where they remained in frontline service until 1929.

The last batch of MB-2’s to be manufactured came from the Curtiss company and used an experimental supercharger that pulled air into the engine to give it greater power. The improvement in performance was spectacular, allowing the plane to reach a then-incredible 25,000 feet in altitude. But in the end the experiment was a failure–the superchargers were mechanically unreliable. There would be no successful supercharged airplanes until the Second World War broke out in 1939.

As the MB-2 went into production in 1920, however, a furious debate was going on in the US military. General Billy Mitchell, a colorful, brash and opinionated figure, was convinced that air power would be the decisive factor in any future conflict, and that large fleets of Navy ships were particularly vulnerable to air attack and were now virtually obsolete. Naturally, this is something the Navy did not want to hear. They argued that no airplane could deliver enough firepower to seriously damage a modern armored battleship. So, after much bluster and heat, it was decided to set up a series of experiments using some captured German leftovers from the war. Both Army and Navy aviators were invited to participate. It became known as Project B.

The first test was on June 21. A captured German submarine, the U-117, was attacked by a squadron of Navy airplanes. She was sunk by the first wave. On July 12, the Army got its turn: a wave of SE5a fighter-bombers and MB-2 heavy bombers with 300-pound bombs attacked the old German destroyer G-102. The destroyer was sunk. On July 18, MB-2’s with 600-pound bombs sunk the German cruiser Frankfurt. And then on July 20, in the biggest test of all, the MB-2’s were sent against the German battleship Ostfreisland, a modern “dreadnought” which naval experts believed to be virtually unsinkable. This time the flight of six MB-2’s used 2,000-pound bombs. Twenty minutes and two bomb hits later, the Ostfreisland was at the bottom of the sea.

Mitchell was right–the days of the big battleship were over. But the Navy continued to resist, arguing that Mitchell’s test was invalid because the battleship had been unmanned and had no anti-aircraft defenses. The debate over the effectiveness of aircraft versus battleships came to an abrupt end on December 7, 1941, and airpower would come to dominate the next World War. Unfortunately for Mitchell, though, his constant verbal attacks in the press on the US military for being “unprepared” and “irresponsible”, eventually led to a court-martial (for “insubordination”) and his resignation.

Of the 110 MB-2 bombers manufactured after the First World War, none survive today. In the 1990’s, the US Air Force Museum began producing an exact replica from original factory drawings, which was complted in 2002. It is currently on display.

The MB-2 bomber also played a role in Hollywood movie history. In 1927 Paramount released the silent movie “Wings”, a story about World War One air combat. Some of the scenes were shot from airplanes, including simulated dogfights. In one scene, an MB-2, painted in German markings to depict a Gotha bomber, is shown in its hangar undergoing an attack from the air. “Wings” was the first motion picture to win an Academy Award for Best Picture.

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