TerraBreak.org: An independent Design/Build/Fly (DBF) support site

I think we have to start off our encapsulation of the 2006-2007 AIAA/Cessna/RaytheonMS Design/Build/Fly competition by giving a big shout out to all the Raytheon and TIMPA volunteers that made DBF happen this year. This is not to slight the traditional cadre of Contest Coordinators, Cessna volunteers, and AIAA personnel. However, Raytheon was out to prove they deserved being a host of the competition... and boy did they. We look forward to returning to Tucson in two years, and drinking in it's character again.

Now lets get on to the planes!

The Contest Coordinators threw down a gauntlet in the rules this year, and it was interesting to see how many teams attempted to pick it up and run with it. That gauntlet was the design challenge of a 2 foot wingspan caused by the 2'x4'x1.5' box, and wingspan and weight being the only RAC factors. The short answer is: "yes" you can get a 9# DBF plane to takeoff in 100ft with a 2ft wingspan. The problem that arose was a matter of insufficient roll stability (or damping), and razor thin propulsion pack safety margins. I'm glad we weren't in Wichita. We commended the pilots for their skill in handling "sometimes" unruly designs last year, this year we can't say enough about their professionalism and dedication to maintaining a safe competition. To say they had their hands full is an understatement.

One of the neat outgrowths of the rules this year was the variety of designs that showed up to competition. Yes, there were a lot of teams with 2' wing spans; but there were almost no two aircraft alike. Even the more conservative "conventional" a/c had a few tricks up their sleeves. It's hard to tell if this was the result the organizers have been looking for from the rules for a long time. If so, man did they ever get it. There were lifting-bodies (yes, plural!), biplanes, monoplanes, a flying pancake replica (UMD), a w-tail, an Ed Lesher Teal look-a-like, but sadly no H-tails(?) :(.

Perhaps one of the most-over looked difficulties of this year's design challenge was the bluff-body effect of the 8"x8" sensor payload. With most fuselage lengths falling in the 4' range, this resulted in most tail-moments in the 2.5-3 foot range. Doing a quick, back-of-the-napkin, calculation results in a constriction angle range of: 6.5-15degs. At this Reynold's number the middle to upper end of this range is quite prone to separation, having dire effects on low-speed directional stability.

The surprise to everyone was MIT's reading/interpretation of the "wingpod" cargo rule for this year. Wingpod legality has flip-flopped over the years in the rules, largely depending on the payload to be carried (it seems). Thus, MIT has proven how important it is to read through the rules with a fresh mind, and take notice of all the little tidbits that are in there.

Even though they didn't win, we have to give OSU some props. Even ignoring their "abbreviated" development schedule, the controllability of their 2' span aircraft was impressive. Considerably more impressive was the different approaches that their two teams followed. The difficulty with being the best for so many years can be having the giant bulls-eye on your back. OSU took on an incredibly difficult design challenge, and rose to the occasion with an excellent performance. The fact that it took one of the premier technical schools in the country world to knock them off the top of the podium should be a badge of honor.

Here are some additional figures to consider:
There were 60 teams that originally responded to the rules. 36 teams successfully passed tech inspection. Over the course of the two days of competition there were (by our numbers) 116 flight attempts. Of those only 31 flights were successful scoring flights, achieved by just 18 teams. That's only 4 fewer teams to make it through tech inspection than last year. But what does this mean? Crashes. There were a lot. However, a significant number of teams kept coming back to have a go again. We certainly applaud their dedication and determination... well all of us but Mike. The photos don't come cheap, and there's a reason they only let a few people cross the flight line. Mike stared down CalPoly's SLO Blow before executing the best softfield-don't-break-my-expensive-telephoto shoulder roll I've ever seen. He's taken our staff t-shirt message:



to heart, and is returning leaner and with a meaner telephoto.

Because TIMPA was a new location for the competition, it deserves some discussion. Yes, we were out in the middle of nowhere, but the again what better environment to "test" such radical designs? Yes, the tent wasn't quite the same as the qounset hut available at Webster field (or the hangar space at Cessna). I'd say it's a toss up about having all the battery pack charging located at one "tent." The limited entry points did end up becoming "choke" points at times. On the other hand, it was an obvious barrier that increased spectator/participant safety. It was nice to have a singular location for all engine testing, that was under the supervision of contest volunteers. This was a giant improvement in participant/spectator safety since it meant that all tests were conducted away from distracted people, and with the supervision of people who keep a premium on safety and can provide some assistance in troubleshooting problems. It also moves the volunteers further away from the role of "bad cop", and having to 'catch' and 'educate' teams about prop safety; instead the volunteers were in a position to make sure that things went correctly from the start and explain the reasons for their actions in an environment of understanding and not confrontation.

TerraBreak.org took a new approach to event coverage this year... by going digital. In addition, we significantly reduced our data collection mission. No lap times. No ground mission times. We're still figuring our way through how best to service the variety of responsibilities we have to your competition: Scribe, Judge, Photographer, Tech Inspector. The move to digital was semi-successful, it reduced how much time we had to sit around Saturday night trying to decipher the chicken scratch we'd scrawled during the day. Unfortunately some technical glitches resulted in some loss of the data, and led to us getting it up on the site late. On the other hand, being digital (and the small size of the PDA) freed us up some to take the data as we had time. This allowed us to focus on tech inspections Friday/Saturday, and then go out and collect data Saturday/Sunday during lulls in the inspections and judging on the flight line. We've got some plans down the road for improving the digital technology, with the end goal of instantaneous updates. Technology isn't quite there yet for that; and we've got some backend work to make it happen. But, we do have a plan for how we're going to provide the best resource for the competitors, while helping the organizers execute/provide/ the venue for you to display your skill, determination, and ingenuity.

So, one last bit of business, is our 'annual' report on how much we donated to other people's pockets so that we could feel the warm glow of engineering excellence.(this will be up soon!)