Advanced Aero Vehicle Group: With Innovation, Comes Risk

The Miners headed to Marietta, Georgia (backyard of event sponsor Lockeed-Martin) over the weekend to fly their heavy-lift airplane.
Dave Althuis reports that their innovative design, incorporating leading-edge flaps, was a big hit with the SAE Aero judges. He says the approach had never been tried before at an aero event and that may be one big reason why the team copped the top score in project design.
And then problems cropped up in the execution of the design:
1. Center-of-gravity: The plane was tail-heavy so they added weight to the front to move the center of gravity forward. Once the plane was properly balanced the total aircraft weight came to 49 lbs. Problem was, the airplane was designed with a maximum take-off weight of only 45 lbs.
2. Engines: S&T’s two engines use a tuned-port exhaust system which must be carefully plotted, balanced and synchronized. Even a few thousandths of an inch can make all the difference, and somehow the tubes weren’t even close to correct. That resulted in too little of the all-important ooomph needed to get even the design weight off the ground, let alone the enhanced gross weight.
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Against all odds, uber-pilot Kelly O’Connor managed to get the craft to claw its way into the air to an altitude of perhaps 10 (yes, TEN) feet, and that’s when the things really got interesting. Seems the altered power-to-weight ratio, combined with the resulting slow take-off speed, caused unpredictable stall effects. In plain english that means “now you’re flying, now you’re not!”
The sudden onset of stall impeded the ailerons’ ability to control flight direction, so the bird refused to turn left, wiping out any possibility of NASCAR sponsorship. And on the right? The spectators, so Kelly had to abort the flight and pancake the plane to the ground. The plane could have been repaired overnight, but any more attempts wouldn’t change the plane’s fatal flight characteristics so they packed it in and enjoyed other teams’ airborne misfortunes.
The good news? S&T’s Data Acquisition System, which measured take-off and landing rolls, worked great in tech inspection. That was a big improvement over last year’s design.
The biggest challenge they faced? Weather. A side effect of April’s deadly rain and storms was that all the Miners’ test flights got rained out, leaving them with no way to verify their design before competition.
Overall they think they managed 6th place out of 7 advanced class teams, not bad for an aircraft that barely flew.
The winners? The Polish team had the only advanced-class certified flight. They lifted a record cargo weight, posted the highest ratio of cargo-to-payload, and have been consistently successful over the past few years. Well deserved!
Oh, yeah, the prize for the best crash? A brand new garbage bag.