While the Hortens and Lippisch were making considerable progress in flying
wing research and development in Germany, the idea was pursued vigorously
in the United States only by Jack Northrop. A few other tailless
prototypes appeared briefly, two of which should be mentioned before
proceeding to Jack Northrop's wartime designs. These configurations were
unique even in a field of aircraft design where the unusual was
Ten years after the first Arups appeared in the 1930s,
another disc-shaped oddity could be seen flying around the Connecticut
countryside. The Vought V-173 "Flying Pancake" was the brainchild of
Charles H. Zimmerman, who built his flying wing while employed as an
engineer with the National Advisory Committee for Aeronautics (NACA).
NACA's light-plane research study of 1933, which provided the incentive
for other tailless designs in the 1930s, also inspired Zimmerman to design
a passenger-carrying aircraft that would land and take off like a
helicopter and once airborne, convert to conventional flight. Perhaps
influenced by the Arup design, Zimmerman built test models that received
The all-movable, or "flying" tail of the V-173 "Zimmer-Skimmer" is quite
evident in this view of the disc shaped aircraft. During its successful
flight test program, the "Flying Pancake" experienced several crashes, but
sustained little damage because of its very low landing peed. Test pilots
Were unable to spin the aircraft and were amazed at its rapid deceleration
as it was pulled into a tight turn.
In 1937, Zimmerman turned to Chance Vought for the
sponsorship that he needed. With U.S. Navy funding, the V-173 was
constructed as a prototype for a high performance fighter, eventually
designated XFSU-1. Powered by two 80-hp Continental engines, the fabric
and wood V-173 was flown for the first time on November 23, 1942, by
Vought chief test pilot Boone T. Guvton. He described the flight as "one
of the most interesting I had made in my career." Control forces were so
heavy that it required two hands to control the aircraft during the short
13 minute flight!
The V-173 enjoyed a successful flying life with 131.8
hours flown by Guyton, Richard Burroughs, and U.S. Navy test pilots.
During the flight test program, which extended to March 1947, the XFSU-1
fighter prototype was designed and built. Powered by two Pratt & Whitney
R-2000-7 radial engines, the V-173 look-alike was designed to fly as fast
as 500 mph and also have exceptional handling at low speeds. The aircraft
became a victim of the jet age, and never progressed beyond the taxi test
George W. Cornelius, who began his experiments on
variable incidence wings in the middle 1920s in California, continued his
innovative trends when he displayed a tailless aircraft with a forward
swept wing in September 1943, at Dayton, Ohio. The aircraft, called the
"Mallard," also featured a variable incidence wing, with two outboard wing
panels that could vary their angle of incidence about a fixed spar
attached to the fuselage. Fore and aft movement of the control stick by
the pilot varied the angle of the wings in unison, causing a pitching
movement. Moving the stick laterally varied the incidence angle of the
wings differentially, producing a rolling moment in the same manner as
produced by ailerons.
George Cornelius of Dayton, Ohio, was a staunch
advocate of the swept-forward wing concept, which lent itself
well to this experimental tailless aircraft of the 1940s. Cornelius
claimed that the combination of variable incidence wing and forward sweep
resulted in an aircraft that was virtually stall-and spin-proof.
The wings automatically adjusted themselves to absorb
or offset unbalancing forces caused by turbulent air, preventing the
sudden displacement of the airplane from its flight path. Although the
airplane flew successfully, it was experimental in nature and was never
Cornelius tried a more specialized application of his
concepts to the expendable fuel transport glider, the XFG-l . Built in
1944 for the U.S. Army, the glider was designed to provide a supplementary
fuel supply for long range bombers. While being towed through the air by a
fuel hose, the glider would theoretically pump about 700 gallons of fuel
to the tow plane, after which the hose and pilotless aircraft would be
released to eventually crash. Only two models were built for test
purposes, the first of which crashed during a spin, killing the pilot.
Requirements for the glider ended with the end of World War II .
The Cornelius XFG-1 was designed as an expendable, pilotless glider to
fuel bombers in flight. Incidence of the swept-forward wings could be
adjusted on the ground between three and seven degrees.
Many of these tailless aircraft and flying wings
preceded, and in some cases overlapped, the efforts of Jack Northrop
during World War II. Aside from a few instances of public acceptance in
the marketplace on a limited basis or a government requirement during the
war, the success of the concept was very limited. The reasons for failure
were diverse-poor design, inexperienced management, inadequate financial
backing, public and bureaucratic indifference, and for Lippisch and the
Horten brothers, being on the losing side in a war.