By Steve Manganelli
Design/Build/Fly (DBF) is a competition sponsored by the American Institute of Aeronautics and Astronautics (AIAA) for undergraduate aerospace engineering college students. The competition is unique in that the rules change every year so the previous years’ experience is not terribly helpful to successive teams. The competition requires fabrication and documentation of a UAV aka R/C model airplane capable of carrying some kind of cargo, or deploy a “sensor” or some item representative of what might be typical of cargo for a UAV. In recent years, the entry has been capped at 100 schools many of which are from abroad. Usually, the process culminates in a fly-off at either the Textron facility in Wichita KS or a model airplane field in Tucson AZ. This year, a “Covid year” things were a little different.
Myself and Steve Neu have been mentoring either SDSU or UCSD DBF teams since 1999 after we were approached at an SEFSD meeting by the leader of the UCSD team; at the time, DBF was only int its 4th year. What was soon clear was no undergraduate aerospace engineering curriculum had R/C model building instruction! The models of the most successful early teams were constructed in Steve Neu’s shop with expert supervision and frequent R/C modeling lessons. Later teams chose to fabricate in their own on-campus labs and over the years we’ve carried tennis balls, softballs, pint water bottles, Estes rockets, water, ping pong balls, various weighted cubes just to name a few.
Fast forward to 2020/2021. This years’ rules, published in early September, 2020 were for a cable extending and retracting sensor which also had to display 3 lights which had to blink in a sequence. The model also had to carry a number of these “sensors” as cargo in simulated shipping containers. The scoring formula forced a compromise between length of sensors, weight of sensors and quantity of cargo sensors to be carried in separate missions. You could make the model as big as you want except that the wingspan had to be 5 feet or less! The first mission required the model to fly the course empty using pass/fail criteria.
Months before the fly-off, there is 5 page proposal due that delineates each schools plan to solve the DBF problem. The organizers use this to cull out the top 110 proposals from the nearly 160 submitted! SDSU’s proposal fortunately passed muster and the team led by Daniel O’Haire was off to the races. The specter of Covid hung over this year’s competition with the continued ambiguity of whether or not there would be an in-person fly-off in Tucson. In February, the 60 page paper documenting the design effort was submitted and in an unusual circumstance, the scores of the papers (which are a factor in the overall score) were announced in mid-March and the fly-off was cancelled; we stood in 37th place overall. The criteria for scoring the video was announced later with a potential to multiply the paper score by up to 10 if all the flight criteria are met.
Steve Neu and I thought this was going to be the end of it as the students were still learning remotely and were not allowed on campus for access to their fabrication lab. I dropped the students a quick E-mail on April 11th, expecting confirmation that they were unable to fabricate a model and their DBF effort was complete.
Imagine my surprise that instead, I was told they were just allowed back in their on-campus lab and they would have a finished aircraft for our inspection on April 14th! Although not ready to fly, the airframe had promise and after going over a list of corrective measures, the all-or-nothing test flight and video production was scheduled for the following Friday or Saturday at the latest, only a day or two ahead of the deadline. Steve Neu and I had a final preflight at his shop on Friday night where we made some more adjustments, set the control throws, changed props, issued a few more corrections and declared the model “ready to fly and video” the following afternoon.
The model was placed on the center of the runway at SEFSD field, the throttle advanced and up she went! The takeoff was the first part of the video requirement, that complete it was now time to deploy the sensor. The command via a separate transmitter was issued to deploy the sensor, however being that it was only about 1 ½ inches in diameter and maybe 8 inches long, we couldn’t really tell whether or not it was deploying. After several circuits of the field, we determined that it wasn’t so a landing approach was made, the landing being the 3rd video requirement. Steve touched down smoothly, the model immediately turned right due to NLG problems and was softly arrested by the weeds. Flight number 2, the sensor clearly deployed and then retracted : success! We now had all of our video requirements which were uploaded to the Organizers’ website where we just awaited our final placing.
Last Friday, May 14th, the final scores were announced : SDSU is 21st place out of 110 Teams and the top scorer among all the California schools participating! Not bad for a week and a half build! Congratulations to Daniel O’Haire and the rest of the SDSU DBF Team for a herculean effort. For general information about DBF, check out the AIAA DBF Website here : AIAA Design/Build/Fly | AIAA .
