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Design… Build… Fly!

Members of The University of Texas at Austin’s Design/Build/Fly (DBF) team showed their Longhorn pride once again at this year’s DBF Competition. Held annually, the competition gives engineering students around the world the opportunity to validate their analytic studies while engaging in real-world aircraft design experience.

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The team's Fujita-13 aircraft. View slideshow.

University student teams are required to “design, fabricate, and demonstrate the flight capabilities of an unmanned, electric powered, radio controlled aircraft which can best meet the specified mission profile. The goal is a balanced design possessing good demonstrated flight handling qualities and practical and affordable manufacturing requirements while providing a high vehicle performance,” according to the DBF Competition summary. Cash prizes are awarded to the top three winning teams and the first place team is invited to present their design at an American Institute of Aeronautics and Astronautics (AIAA) conference.

The year’s event was hosted by AIAA and Cessna Aircraft Company/Raytheon Missile Systems and held at TIMPA Field in Tucson, Arizona, April 19-21.

Each year, the competition’s design missions and challenges change, giving student teams experience with various design requirements. The focus of this year’s competition was to takeoff within a prescribed area on the runway and carry hobby rockets. Each aircraft was required to takeoff within a 30’ x 30’ square for each of the three missions.

The Cockrell School’s Department of Aerospace Engineering and Engineering Mechanics team spent months designing their 2013 competition aircraft, Fujita-13, to meet the mission requirements.

Team members began preparing for the competition in August of last year after receiving the new set of rules. Many hours were spent designing and building the aircraft in the Air System Lab, followed by test flights at a local airfield throughout the spring semester.

dbf team 2013

The 2013 UT Design/Build/Fly Team with their airplane, Fujita-13, on the competition runway in Tucson, Ariz. View slideshow.

“We designed our airplane for a relatively high thrust-to-weight ratio to improve our takeoff performance. We did this by increasing the number of cells in our battery packs from what we normally would have used, which increased our propulsion system's voltage and power,” DBF team lead Anthony Ly said. “We also performed a lot of takeoff tests before competition at the Austin Radio Control Airfield to make sure we could satisfy our takeoff requirement.”

Preparations for the competition were running smoothly until the Monday before the competition, when the team ran into a last-minute hiccup.

The motor mount on the airplane broke and could not be repaired. DBF members had no choice but to spend long nights in the design lab that entire week, modifying a backup competition airplane that would fly in place of the one they had been building and flying all semester.

“We had to work around the clock to make sure the backup plane was competition ready,” said chief engineer Charles Zappala.

Once the team arrived in Tucson with their modified airplane, they continued to work all day to perfect their plane. Final tweaks were made right up until the technical inspection took place two days later.

While Fujita-13 sailed smoothly through inspection and the first two missions, the third proved to be a bit more difficult.

The first mission, “Short Take-off,” was a speed test; teams were required to fly their airplanes as many laps as they could around the course in four minutes. The UT Austin team flew five laps in the time limit before coming down for a clean landing.

The second mission, “Stealth Mission,” required internal storage of rockets within the main fuselage. Each airplane was required to fly three laps carrying as many small hobby rockets as it could handle. Just before the close of the first day of competition, Fujita-13 completed the second mission while carrying four internal rockets.

The third and final mission was a mixed payload flight. Each team was randomly assigned a combination of four rockets to carry aboard their planes inside the fuselage and on the wings. The rockets carried in the third mission had a total weight of three pounds and made the “short take-off” requirement more difficult. The airplanes were required to fly three timed laps. Winds started off slow for UT Austin’s Fujita-13 but picked up just in the nick of time to take off and fly the third mission successfully.

“We really needed the wind to pick up for our third takeoff,” said Mark Maughmer, who piloted the plane. “During the third round of takeoffs before us, there was no wind. But right as we were set to fly, a perfect amount of wind kicked in, in the perfect direction. As soon as Fujita-13 was in flight, the wind stopped.”

But the UT Austin team still flew the mission successfully and managed to place seventh out of 60 competing teams in the DBF Competition. The team was also one of only 12 teams to complete all three missions. Of the 60 teams, 44 were from the United States, and 16 were international.

Team lead Ly said he is grateful for the chance to work on and lead an engineering design team as an undergraduate student in the aerospace engineering program.

“DBF has given me the opportunity to create an aircraft out of the knowledge I’ve learned in class in a practical way,” Ly said. “On paper, a design may work but when you actually start building, things don’t always go as planned. We had to problem solve, get our hands dirty and pay attention to details, like the additional weight that glue and resin adds to an aircraft – these are the kinds of things that can be hard to account for on paper.”