CUE 2007 Home >> Features >> Design, Build, Fly — Radio-Controlled Aircraft Give Students a Mission

CUE 2007
Aerospace Engineering Sciences:
Design, Build, Fly — Radio-Controlled Aircraft Give Students a Mission

Aerospace engineering students Matthew Osborn and Chelsea Goodman work on building this year's radio-controlled aircraft, which will be a biplane with a conventional tail.

For aerospace engineering junior Spencer Riggs, the American Institute of Aeronautics and Astronautics' annual Design-Build-Fly Competition offers a valuable opportunity to apply classroom theory to a real aircraft. "We actually get to build things and test them, and see if they will work," says Riggs, who is serving as project manager for this year's DBF team after two years of prior involvement.

The competition, which is co-sponsored this year by Cessna Aircraft and Raytheon Missile Systems, challenges students to design, fabricate, and demonstrate the flight capabilities of an electric-powered, radio-controlled aircraft designed to meet a specified mission profile. Through their participation, students gain first-hand knowledge of all major aspects of small aircraft engineering processes, including wing optimization, construction techniques, stability and control, and team dynamics.

The goal is a high-performance vehicle with a balanced design; demonstrated flight handling qualities; and practical, affordable manufacturing requirements. Each team's overall score is a combination of its design report, rated aircraft cost, and flight scores during the April 20–22 competition, to be held in Tucson, Arizona, this year.

CU-Boulder students first entered the DBF competition in 2002 under the faculty leadership of Brian Argrow, director of the Research and Engineering Center for Unmanned Vehicles in the college. RECUV is a university, government, and industry partnership dedicated to advancing knowledge and capabilities in unmanned vehicles for scientific, industrial, and military applications.

Osborn and Lindsay Marek test their 2005 V-tail aircraft at the Boulder Aeromodelers Field.

Although the students each put in as many as 10 hours or more a week on DBF throughout the academic year, the competition is entirely an extracurricular activity at CU. Team membership is open to all interested students. The Undergraduate Research Opportunities Program has funded the construction of the aircraft and some of student travel to the competition site. Additional funding has been provided by the Engineering Dean's Office, the Department of Aerospace Engineering Sciences, RECUV, and Lockheed Martin Space Systems.

"Many schools show up with an airplane that can fly, so it's completing the mission with accuracy and efficiency that determines the winner," says Argrow. "Having a mission forces students to design to the mission requirements. It's a systems engineering problem that is ideal for our program." Missions typically involve carrying two alternate payloads, which have to be changed out between flight segments. This year's payloads include a 12-inch softball, which simulates a reconnaissance camera, and an L-shaped air sampler tube that must be mounted on the aircraft's nose.

Argrow says the students organize themselves at the beginning of each school year. About 25 students are now working in three sub-groups to complete all tasks. While one group focuses on the fuselage and mission analysis, a second group focuses on aerodynamics, including the design of the wings and tail, and a third group devotes itself to propulsion, including choice of motor, propeller design, and batteries.

CU's 2005 DBF team, pictured at the competition in Maryland, included (clockwise from lower left) Stefan Elsener, Matthew Osborn, Lindsay Marek, Michael Gentry, Grant Bovee, Brian Argrow, and Cory Dixon.

This year, the CU team is building a biplane with a conventional tail and pusher configuration so that the propeller won't interfere with the nose-mounted payload.

So far, CU's best performance in the competition was in 2006 when the team placed 12th out of 49 teams. Ironically, that happened less than 24 hours after the aircraft crashed and was severely damaged during its first competition flight.

"It worked fine in Colorado but experienced low-speed flutter in the higher density air in Wichita," Argrow recalls. Students spent all night rebuilding and stiffening the wings of the aircraft, which then flew beautifully the next day.

"It's interesting to fly these aircraft because each one is unique and we don't really know how they're going to behave," Riggs says.

Student team website: http://dbf.colorado.edu
Department website: www.colorado.edu/aerospace