Dedicated to the Promotion of Electric Propulsion in all types of Aeromodeling


By Steve Manganelli

The American Institution of Aeronautics and Astronautics (AIAA) Design-Build-Fly (DBF) competition concluded April 21st in Wichita KS and SEFSD was there! Myself, design mentor and Pilot/Safety Officer Steve Neu supported both San Diego State University and my alma matter University of California San Diego at this competition among undergraduate aerospace engineering student teams.

Though not unique among undergraduate competitions, DBF is unique in that the missions change every year so there can be no year over year design iteration. This year’s predominant constraints were 20 ft takeoff, 5 ft wingspan and folding to 2 ½ feet for parking. The parking fold configuration among the 93 teams present at the flyoff were a mixture of high wing rotators, tip folders and tail/fuselage folders aka “scorpions” (think about it..) SDSU chose the rotator and UCSD the tip folder. Mechanisms for short takeoff included twin motors and “blown” flaps, just flaps and just a lot of power/high angle of attack. The cargo consisted of “peg dolls” and a 3” X 3” box to ballast as you choose for more points. Three of the 4 missions used normalized scoring where the best team received a 1.0 times the paper score and the others a proportional fraction.  Georgia Tech for instance chose to optimize the ground mission which required changing between the 2 payloads as fast as possible. This required them to use only a small number of peg dolls which in turn cost them on the mission where the larger number of peg dolls was favored. Their time of 36 seconds/4 peg dolls compared favorably with SDSUs 290 seconds/50 peg dolls. As it turned out, neither SDSU nor UCSD completed the peg doll flying mission and UCSD crashed spectacularly on their last mission attempt Sunday afternoon.

The flyoff began with publication of the flight order on the 16th of April. The flight order is the ascending  rank of the paper scores : SDSU scored an inauspicious 80 th position and UCSD a little better at 65 th. However, you’re not even eligible to fly until after you’ve passed “Tech Inspection” where predominantly non-modeler, local aerospace professionals scrutinize the models for rules compliance and safety. By the time SDSU passed tech inspection and joined the flight queue, the contest was nearly 1/3 over. We made the gratuitous “no-payload” flight early on the 20th and the box ballast mission very late in the day on the 20th. We climbed from 80th position to 37th and were pretty happy that evening.

Our students arrived early on the 21st to take their place in the ground mission queue where they executed their fasted time ever. The final day of the contest dawned sunny and calm; unusual for Wichita in Spring. By now every team capable of flight had passed tech inspection and the flight queue was very long. Plus, each crash required sending out the paddy wagon to collect the debris as the site is a full scale airport and leaving FOD was not an option. Some of the crashes were just no-start or no takeoff in 20 feet some were mid-air wing folds with pretty spectacular pile driving results. The so-called garbage bag crashes delayed the one-at-a-time flight order and we were becoming nervous as the day waned. When our turn came up, the winds were nearly calm, a condition we did not have the opportunity to practice at SEFSD field.  Pilot Steve Neu held full up elevator and poured the coals to it, but she didn’t make it up before the 20 ft line. Having the rest of the 5 minutes for the mission, Steve brought it around for a smooth landing for another try but while carrying the plane back to the starting, 2 of the passengers bailed out of an escape hatch and our last mission attempt was black flagged with no score!

SDSU moving from 80th to 47th is one of the better improvements at the contest. UCSD unfortunately was one of the garbage bag crashes coming in at high speed at a shallow angle with a very long debris field and slipped to 74th from 65 th. Steve Neu and I made the San Diego-impossible dash to the Wichita airport in less than 1 hour for our ride home. There it is, DBF 2024 complete and SEFSD completes another opportunity to serve the San Diego’s University community. For more pics, scores and details, go here : 2024 Competition Scoring | AIAA .