Boeing Model 306

A flying wing is a tailless airplane accommodating all of its parts within the outline of a single airfoil. The flying wing is still viewed as a unique and unconventional aircraft concept. There were a variety of reasons for the slow acceptance of flying wing type vehicles. From a technical point of view, the dominant issue was stability and control, which to this day continues to plague this class of vehicle. As a result, flying wing aircraft were limited to missions comprised of only low lift (cruise) conditions. In addition to the technical issues, there were cultural issues faced by this class of aircraft that consisted of negative public perceptions and politics. In the first half of the 20th century, which was the most prolific period of flying wing development, these two issues severely restricted technical discussions and as a result the opportunity to mature this concept was lost.

Since the beginning of manned flight, flying wing designs have been pursued with creativity, passion, and braverr by man visionaries. The early pioneers of flight, beginning with Otto Lillienthal of Germany, who developed the first all wing glider which demonstrated the first sustained controlled flight in history. Other pioneers included Alphonse Penaud of France, Clement Ader of France, and Jacob Ellehammer of Denmark, recognized the potential of an aircraft comprised primarily of a wing. It is clear from the literature and available data, that Germany has led the development of the flying wing concept. The work of Lillienthal, Lippish, and the Horten brothers is impressive by all measures.

In American aviation, the flying wing is most closely associated with Jack Northrop (1895-1981) and his company. Northrop's contribution to fbing wing development, within the United States, is without dispute and is well documented. Northrop built several well known tailless aircraft from the late 1920s through the late 1940s; these pioneering aircraft progressively demonstrated the basic soundness of the concept, eliminating the weight and drag of a conventional fuselage and tail while utilizing a much higher percentage of total surface area for lift and load-carrying. Perhaps influenced by the promise of Northrop's flying wings, several other US manufacturers examined the feasibility of the flying wing layout, one of which was Boeing.

During the interwar period, Boeing had been an innovator, producing such notable aircraft as the Model 247 airliner, the first modern passenger airliner, and the P-26 "Peashooter," the first all-metal monoplane fighter ordered in quantity by USAAC. However, the company tended to shy away from more radical layouts such as those pursued by Northrop. In a 1999 interview with retired Boeing vice president Jack Steiner, who worked on such famous aircraft as the B-17 and Model 727, he mentioned that the consensus view at Boeing during this period was that tailless aircraft suffered from low stability and large pitching moment problems which were not easy to solve, making them generally unsuitable for production bombers and transports. It was only in 2006 that this series of designs came to light.

Nonetheless, Boeing did not ignore the concept entirely, drafting 5 tailless studies in 1935 under the Model 306 designation. Ranging in size from an enormous heavy bomber to a diminutive pursuit aircraft, the Model 306 studies all shared a high aspect ratio wing with an unusual control surface configuration, in which external elevons were attached to supports well aft of the trailing edge. These allowed the air to flow over the whole airfoil shape of the elevon, generating more force than a more conventional installation. These elevons also had a greater moment arm around the axis of the wing.

While Boeing was working on the XB-15 in the 1930s that would ultimately lead to the smaller but more advanced B-17 Flying Fortress and B-29 Superfortress, the company was engaged in a secret parallel project to develop a flying wing bomber that used some of the XB-15 features but was expected to exceed the performance of the XB-15 in every aspect. With a crew of 10, the Model 306 bomber had a swept wing of 140 feet in wingspan with a fuselage 60 feet in length. Four forward-mounted engines on the wings used 850-horsepower Allison V-1710 12-cylinder liquid cooled engines. Having a fully-retractable taildragger landing gear layout, the Model 306 bomber would have had a range of 5,000 miles with a 2,500 bomb load. Defensive armament consisted of a mix of 50-caliber and 30-caliber guns.