Mark Stull Dies in Crash of New Design
We are sad to announce that ultralight experimenter Mark Stull died on the afternoon of November 15, 2011, at Ducote Air Park near San Angelo, Texas, during the first test flight of his newest ultralight aircraft. A witness said the plane had just taken off for its first flight when it stalled at about 50 feet and impacted the ground near the runway.
His previous design, a ring tail, won the Outstanding Fixed Wing award in the ultralight category at the 2011 Sun ’n Fun International Fly-In & Expo held April in Lakeland, Florida. He wrote about the aircraft in an article that was published in the April 2011 issue of Light Plane World. Read the story here and learn more about his design philosophy and the ringtail ultralight. He loved to build ultralights and solve challenging problems. His newest design used a weight-shift trike wing kite by North Wing for the main wing of an otherwise conventional-looking craft. He told a friend that he just wanted to do something different—use a trike wing but put a tail on it and make it fly.
We probably will never know exactly what caused the crash. The NTSB will not investigate the accident because it was an ultralight. No report is expected. The witness (another resident of the air park) stated he taxied it a few times, took off, and climbed with wings level to 50 feet. It then went to the right. A wing dropped and it stalled. There are no details available about the design or its control systems except for the photograph. The configuration is so unusual that it raises many questions.
Adding a tail to a swept flex wing designed to fly without a tail takes the plane into uncharted territory, something that may have appealed to the experimenter. It sports an apparent full flying vertical tail coupled with a horizontal stabilizer with a pronounced reverse camber (flat on top). A few highly experimental hang gliders have been built with very small tails, but they are rare. Also trike and hang glider wings roll in the lateral axis in response to weight-induced wing warping rather than from yaw inputs like rudder-controlled airplanes. Without testing in a wind tunnel or the use of scale models, speculation about its behavior in flight is just that.
A self-taught mechanic, Mark was said to be a private, reserved person whose main hobby was building airplanes. He was also an accomplished musician who played and built flutes, and he taught western ballroom and line dancing. He told a Popular Mechanics reporter he had many near-death experiences and that he was a thrill seeker. His brother Roland said, “He really wanted to get the most out of life with everything he did.”