GAX: In search of a mission after World War I

The Army Air Service was populated with proactive pilots and planners who gained firsthand combat experience in World War I. To their chagrin, the years immediately following the war were characterized by a slumbering lack of national initiative on an air policy, as explained by then-Lt. Clayton Bissell.

Bissell and his compatriot Billy Mitchell looked at bombardment and its adjunct, ground attack aviation, as fertile fields for sowing a core mission for the Air Service.

In 1919, the Air Service solicited proposals from the aviation industry for a ground attack aircraft, specializing in heavy firepower and protected by armor plating in an effort to ensure its survival in low-altitude battlefield warfare.

The Army designed a twin-engine pusher triplane to meet the need, and built the prototype as the GAX or Ground Attack Experimental.

The machine won no beauty contests, with its truncated nose and oversized rudder. Nor did it win friends in the flying community, as the weight of the armor and armament taxed the ability of two Liberty engines to propel it.

The immediate postwar period was a time when aircraft manufacturers scrambled for work, and the small but growing Boeing company won the bid to build 20 GAX aircraft under the designation GA-1. The order was quickly reduced to 10 of the unwieldy and ungainly aircraft.  

The twin pusher Liberty engines were mounted in armored nacelles on the middle of the three wings, with a gunner’s emplacement in the front of each nacelle contributing to forward ground attack firepower. The gunners and the pilot all had armor protection with slits or shutters providing the needed visibility to do their tasks.

The GA-1 production variant was capable of carrying eight .30-caliber machine guns and one 37-mm cannon.

First flight of a GA-1 came in May 1921.

Aerodynamics left a lot to be desired and the pusher Liberty engines suffered from cooling issues. All 10 were delivered to Kelly Field in Texas, where they survived until 1926 before scrapping.

Still enamored with the idea of an armored ground attack airplane, the Air Service developed the GA-2, a single-engine biplane. Boeing delivered two of this model to McCook Field in Ohio, for testing beginning in December 1921. The engine specified for the GA-2 was an untried Army design producing between 700 and 750 horsepower.

The GA-1 had a gross weight of more than five tons; the GA-2 topped out at a bit over four and a quarter tons. The big GA-1 had a service ceiling of 9,600 feet — not an issue as long as its intended combat operations did not approach battlefields at high mountain elevations. The smaller GA-2 had a service ceiling of 12,000 feet.

The Air Service, later Air Corps and Army Air Forces, had an evolving relationship with ground attack aviation up through World War II. While some Second World War bombers like the B-25 and A-26 employed bolt-on armor plating to protect the crew, this latter day shielding was less penalizing in aircraft performance than the sheathing on the GA-1 and GA-2. Speed and surprise favored ground attack in World War II.

The GAX was designed by the Air Service’s Isaac Laddon. If the GAX was not a career high point, Laddon went on to become a designer at Consolidated Aircraft where he is generally credited with successes like the B-24 Liberator, produced in larger numbers than any other American bomber of World War II. 

And Lieutenant Clayton Bissell retired from the Air Force as a major general in 1950, after a career that included espousing the value of bombardment aviation and occasionally running afoul of fighter advocate Claire Chennault of Flying Tigers fame during World War II. 

(This column features photographs from the collection of the late Walter J. Boyne, author and former director of the National Air and Space Museum. Walt was a friend and mentor for decades. Following a pandemic delay, Walt’s interment in Arlington National Cemetery was held on May 13, 2021. Walt’s eclectic enthusiasm for aviation history lives on in his photographic collection and in the many aviation books and endeavors he created.)