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Convair chief test pilot Ellis “Sam” Shannon was the first to fly the radical supersonic seaplane, the Convair F2Y Sea Dart.

Delta-Wing Trailblazer

By Robert Bernier
4/1/2017 • Mag: Aviation History Personalities

Sam Shannon was that rare example of an accomplished test pilot who never crashed an airplane and refused to brag about his exploits.

Mounted atop a pole outside the San Diego Air & Space Museum sits a blue delta-wing jet aircraft sporting skis and a porthole-like windscreen that looks like it could have been designed by Jules Verne. This strange-looking craft often draws double-takes from visitors walking by. Built in an age when futuristic designs flowed freely from the drafting tables of America’s aircraft manufacturers, the Convair XF2Y-1 Sea Dart was first flown by test pilot Ellis “Sam” Shannon, a soft-spoken Alabamian who began his long, colorful aviation career piloting “rag and stick” biplanes—and finished up with experimental delta-wing jets.

Born in 1908, Shannon started U.S. Army Air Corps flight training in 1929 and went on to fly lumbering Keystone biplane bombers during the early 1930s. With few advancement opportunities available in the Air Corps during the Depression, he embarked on a series of foreign adventures worthy of the once-popular “Terry and the Pirates” comic strip.

In 1932 Shannon eagerly accepted a position training Chinese pilots for Chiang Kai-shek’s air force. After three years in China, he returned to the U.S. for another brief stint with the Air Corps, before the Glenn L. Martin Company tapped him for a sales demonstration tour of its B-10 bombers in Latin America. There, he made a name for himself by successfully competing against German and Italian airmen peddling their countries’ warplanes in the region.

Shannon piloted the Convair XF-92A, the world’s first delta-wing jet, on its maiden flight in September 1948. (National Archives)
Shannon piloted the Convair XF-92A, the world’s first delta-wing jet, on its maiden flight in September 1948. (National Archives)

Impressed with his technical skill and competence, in 1939 the Martin Company selected Shannon for yet another foreign assignment, this time to French Morocco. Based in Casablanca, he led a team tasked with assembling and check-flying Martin Maryland bombers destined for the French air force. With the fall of France in 1940, the U.S. Navy hastily evacuated Shannon and his team.

Once back in the States, Shannon began learning the test pilot trade in earnest by flying new Martin aircraft earmarked for America’s accelerating military buildup. Among the airplanes he test-flew were the hot but controversial B-26 Marauder and the gigantic Mars flying boat.

In early 1943, opportunity knocked, and Shannon migrated to San Diego to head up the Flight Research Department at Consolidated Vultee (later Convair). As chief test pilot, he conducted developmental flights on everything from heavy bombers, such as the XB-32 Dominator, to advanced flying boats.

The immediate postwar years were exciting times for aircraft manufactures, then in a mad scramble to develop designs utilizing jet propulsion. New Convair designs came fast and furious, as America sought high-performance warplanes able to counter the emerging Soviet threat. And Shannon was right there to test them, piloting the initial flight of the XB-46, a sleek four-engine jet bomber, on April 2, 1947. Although he praised the prototype’s handling qualities, it would lose out to Boeing’s sweptwing XB-47 proposal.

With the Cold War heating up, the U.S. Air Force, alarmed about the possibility of nuclear-armed intruders suddenly appearing high overhead, called for supersonic interceptors able to zoom to altitude and engage enemy bombers. Convair engineers thought the best planform for transonic flight was the delta wing, and to evaluate an ambitious blending of jet propulsion with untested delta-wing theory, constructed the Model 7002 (later designated XF-92A).

Shannon piloted the XF-92A on its maiden flight from Muroc Dry Lake in September 1948. It was the world’s first delta-wing jet to fly. A one-off built as a research vehicle to test the aerodynamic properties of delta wings, the XF-92A paved the way for a series of Convair aircraft culminating in the USAF’s “ultimate interceptor,” the F-106 Delta Dart, and its first supersonic strategic bomber, the B-58 Hustler.

“By making that first flight in the XF-92, Sam kicked off the delta-wing world,” said Frank Thompson, a former Convair executive and Shannon’s close friend. “And in all those years of test flying, he never crashed an airplane.” Thompson fondly remembers Shannon as a tall, courtly Southern gentleman who picked up his nickname from lyrics (“there goes Sam”) of a popular tune of the time because he always seemed to be coming and going on test flights.

“Sam liked the deltas best,” recalled Thompson, and his next challenge was the Sea Dart. In 1948, concerned that supersonic aircraft operations were then incompatible with carrier duty, the Navy launched a contest for a supersonic seaplane fighter. Convair won with its innovative twin-jet proposal for a seaplane that took off and landed on retractable hydro-skis. Five were built.

Shannon beaches an XF2Y-1 Sea Dart after taxi tests in San Diego Bay on December 17, 1952. (National Archives)
Shannon beaches an XF2Y-1 Sea Dart after taxi tests in San Diego Bay on December 17, 1952. (National Archives)

Shannon was the first to fly this radical flying boat in April 1953. Once airborne, the Sea Dart flew well enough, but takeoffs were a challenge as the plane’s skis hammered the waves near liftoff speeds. Shannon reported that the pounding during takeoff was bad enough to blur his vision.

“The 1950s were the glory years for Convair,” said Bob Johnston, a former engineer who once worked for Shannon and is now an archivist at the San Diego Air & Space Museum. “Shannon was always approachable,” he noted, “and always seemed so low key, so confident, that any flight was routine. Yet many of his flights were among the most challenging a test pilot could face.”

In a period of just eight years, Convair built and flew six different delta-wing aircraft types. Although the Sea Dart program was ultimately canceled, Shannon had a hand in developing Convair’s F-102A Delta Dagger, which entered production as the USAF’s first delta-wing fighter.

Shannon retired from active test flying in his late 40s to become a respected flight test manager at Convair. He would continue to lead and inspire younger men until his retirement in 1974 at age 66. Shannon died in 1982.

Today, Shannon is well remembered among Convair alumni. Jerry Butsko, a former engineer, credits him as “a true aviation warrior—a positive, professional mentor who didn’t blow his own horn.” And Johnston, who calls Shannon’s exploits legendary, is campaigning to induct him into the International Air & Space Hall of Fame. “Shannon logged first flights in many aircraft,” he pointed out, “among them the XB-46, XF-92, Model 110 and 340 prop airliners and Sea Dart.”

Johnston succinctly summed up the accomplishments of his personal hero: “Most test pilots had one first flight in their careers; Shannon had a career of first flights.”

This story was originally published in the May 2017 issue of Aviation History magazine. Subscribe here.



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