U of T engineering students make aviation history

Human-powered ornithopter becomes first to achieve sustained flight.

Comments Off on U of T engineering students make aviation history September 23, 2010
Mike McLeod

The Snowbird ornithopter and its creators, engineering students at the University of Toronto Institute for Aerospace Studies
Photo courtesy of Todd Reichert, University of Toronto Institute for Aerospace Studies (UTIAS) and the University of Toronto

University of Toronto’s human-powered flapping wing aircraft, the Snowbird, made aviation history over the summer when it became the first ornithopter to maintain sustained flight. The world record setting flight took place at the Great Lakes Gliding Club in Tottenham, Ont., on August 2 and was witnessed by the vice-president (Canada) of the Fédération Aéronautique Internationale (FAI), the world-governing body for air sports and aeronautical world records.

Unlike other human-powered aircraft, which have fixed wings and gain air speed from a propeller, ornithopters produce thrust and lift solely from the flapping of the craft’s wings.

Although other attempts have been made to create human-powered ornithopters in the past, none were able to maintain air speed or altitude and simply glided to the ground.

That is, until the U of T’s Snowbird. Under the power and piloting of Todd Reichert, an Engineering PhD candidate at the University of Toronto Institute for Aerospace Studies (UTIAS), the ornithopter sustained both altitude and airspeed for 19.3 seconds, and covered a distance of 145 meters at an average speed of 25.6 kilometers per hour.< "The Snowbird represents the completion of an age-old aeronautical dream," says lead developer and project manager Reichert. "Throughout history, countless men and women have dreamt of flying like a bird under their own power, and hundreds, if not thousands have attempted to achieve it. This represents one of the last of the aviation firsts." Over the past four years, the UTIAS team has been in design and development of the Snowbird. Weighing 94 pounds but with a wing span of 32 meters (105 feet), the construction and mechanics of the ornithopter matches that of birds. Instead of hollow bones, the Snowbird's inner skeleton is made largely from carbon fiber tubes. The wing ribs and smaller components are balsa wood and foam covered in a light-weight Mylar skin. Similarly, instead of a bird's large pectoral muscles, the pilot's legs push on a platform inside the cockpit connected to bracing wires that pull wings down. The torsion of the carbon fiber tubes pull the wings back up for the up-stroke. However, Reichert says moving the wings up and down is fairly straight forward. The challenge is getting the wings to twist predictably and precisely down its length. This is the only way, he says, the wings achieve the proper angle of attack during the up and down strokes and thereby produce both positive lift and thrust. "For the design, we primarily used simulation software that we coded ourselves that calculates the how the structure will flex under aerodynamic loads," Reichert explains. "The wing has to twist at just the right magnitude and phase along its length to achieve efficient flight. It's called aerodynamic tailoring and that's the tricky part of designing an ornithopter."

HPO MVI 0057 from U of T Engineering on Vimeo.

In addition to drawings made by Leonardo da Vinci in the 15th century, the design of the Snowbird ornithopter stems in large part from the work of UTIAS Professor Emeritus James DeLaurier, who made aviation history in 2006 with the design and construction of the “The Flapper,” the first motorized, human-piloted ornithopter to achieve sustained flight. For the Snowbird project, Dr. DeLaurier served as faculty advisor.

In addition to Reichert and DeLaurier, the development team was comprised of Cameron Robertson (MASc 2009, UTIAS) as the chief structural engineer; community volunteers Robert and Carson Dueck. In addition, more than 20 students from the University of Toronto and approximately 10 exchange students from Poitiers University, France, and Delft Technical University, Netherlands, also participated in the project.

Reichert, who lost nearly 20 pounds in training for the event, says that the August flight was most likely a one time event. Instead, he says the Snowbird may likely become a museum piece.

“I’m curious to see where this will go,” he says. “When the Wright Brothers flew, they thought there was no practical application for aircraft. I’m curious to see who gets inspired and what might come out of this.”