Oh, and what power system are y'all using, Jeremy? We're using the Astro 60 geared on ~36 2400 mah cells. We get about 11 lbs of thrust from this setup, and it lasts for nearly 5 minutes.

What prop are you guys using? I seem to recall maybe a 24X12?

We don't have quite the headroom that you guys do on propulsion. We run an Astro 60 w/superbox turning an 18X18 APC on 40 CP1300's. Static, it draws around 29 Amps, and we get between 2.5 to 3.5 of WOT time in the air, depending on mission, speed, etc. Static thrust is about 9 lbf uninstalled, and drops to around 8 installed. Our takeoffs aren't quite as authoritative as the one I witnessed SWAG-1 do, and we have less runtime, but I think our plane might be a bit faster. Depending on wind conditions, we may have energy trouble with the radome mission, but with management, I don't think it'll kill us.

I noticed that Junior has no apparent inlet for motor cooling. Have you guys checked motor temp after flight? Bryan had called me to consult about some battery troubles - perhaps the motor is overheating. Ours needs a decent amount of air to stay cool, and we even added a heatsink. If nothing else, it certainly looks cool!

Oh, if anyone wants to try out the Belle, I'm attaching my RealFlight model of it. It looks like a P-51, but flies like our little beast. Takeoff is actually easier with the real thing, though. Gotta hate that Realflight landing gear model. Just unzip the files into your Planes directory. Both the aircraft and the engine are in there.

The Belle got a set of wingtip skids, too. These long-winged planes with high CG's need 'em. Mike Cross even touched one of them on Saturday. How did you guys approach it? We used some music wire "feelers" that do a nice job of popping the wing back up, but not too hard. I like 'em a lot, as I was breaking ailerons when I'd try to recover from a tip-down. Since the aileron needed to go down on the tip that was down, the corner of it wound up scraping - a great way to break loose a horn. Now, the skids stop it short, and take care of some of the recovery by themselves.

Also, how does the SWAG platform handle wind? I've found that the Belle has a real tendency to weathervane, making taxi operations in strong wind either difficult or impossible. Does your trike gear help with that, or have you even had to operate in windy conditions yet?

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I didn't see that fine point in the rules about the antenna view, just that it had to be 3 inches from structure.
A later redraw on mine places the thing with the flat sides vertical, behind the fuselage, so the round side faces the airflow.
And thinking further, it could be mounted on the "sensor" box so that after the box is deployed, it will rotate to the upright position.
Just shows what a leaking mind can come up with! (Since finding a small r/c Humvee isn't panning out.)

You shouldn't read into rules the intent.
If it's not specified, it's not a rule.
For instance, both these installations fit the rules in my opinion.
Unless there's a clarification somewhere, the antenna need only be spaced off the airframe... orientation not specified.

Paul, the 360 FOV requirement was actually made in the FAQ:

"Question: Can fairings be applied to the fuselage that “in effect” fair the antenna if they remain at least the specified 3” away.
Answer: No. The statement “the antenna must not be faired in any manor” can also be viewed such that the “antenna must have an unobstructed 360 degree horizontal field of view”. An exception to the field of view will be made for the vertical tail(s) and/or wing struts. "

Otherwise, your "ahead of the nose" configuration would be an extremely smart way to go - the wake would impinge on the fueslage and reattach, substantially reducing the drag increment from the radome. Balancing would be the only problem I see, and could be taken care of by moving the payload for that config.

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Prop clearance of the deployed payload is a problem. How to get the plane past/over the box after it's dropped, and not have the prop hit it...
The number of ways to skin this cat....

Not if you pitch the payload out the side!

Sound crazy? Yep. It works, though.

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That's what I thought you guys were doing...

Jeremy,

I originally installed angled plates in an attempt to direct the inlet air around the sides of the batteries, but those have since been removed. I also cut louvers in the tops of the battery boxes. The batteries seem to be delivering more power and staying cooler now. Heatsinking the motor sounds like a good idea.. our gets almost too hot to touch after flight. Regarding the Astro 60, it seems like there's some animosty towards us because Astro seems to be telling people that MSU got their last 60 for a while

Our wingtips just have the small nylon GP wingtip skids installed so that the wintgip doesn't get torn up on tip-overs like on the last one. They aren't there to prevent the tip, just minimize the damage. Because of the tall LG we try not to taxi SWAG. It will taxi, just tends to tip onto a wingtip if a corner is taken too fast. The nosewheel configuration keeps it straight on takeoff until the tail can aerodynamically keep the plane straight.

We flew today in a 10-15 mph crosswind and she handled fine. Our pilot didn't report any weathervaning tendancies. We got off in 120 feet no problem witht he full load. This could be the end of our flight testing, however, in order to reduce the risk of a mishap.

Have you tried the 4-lap mission with box and antenna? We can complete it, but not with much power to spare, even with our 2400 mah packs. We are swinging a 22-14 prop.

We assembled our plane in 20 seconds today without even trying to do it quickly. We hinged both our main gear and nosewheel and it just takes a quick flick of the wrist to latch it. Our aileron servos plug in when the wing panel gets plugged in. It's a lot different from our last one.

Have you tested your box-firing mechanism yet? I was just wondering if the kickback from the box would try to tip your plane over. I really want to see it in action!

Thanks for looking up the antenna thing... it *was* in an FAQ and not in the original rules. MSU scrapped the twin boom design after we asked them about that and they answered in the FAQ. I'm almost glad we did, because we see minimal effects from the antenna where it is now. It's not as big a deal as we once thought.

Hopefully Bryan gets updated pics of SWAG Jr. up soon!

Haven't done the radome mission in its entirety yet - that's on tomorrow's agenda. However, given this thing's climb rate and glide ratio, I doubt we'll be in too much trouble there. Even if I can't fly it WOT the entire time, I'm pretty sure that I can fly a motorglider type profile if needed. Also, while our setup doesn't take off quite as well as yours, we do fly faster and draw less current, I think. It's all in the tradeoffs. What does your setup draw static? Motocalc seems to predict 40ish amps... sound right?

And yes, we've successfully dumped the payload several times. Works great, and has no tendency to knock over the plane.

Well, off to bed.

Photos of most of the 2003 SAE AeroDesign West entrants:
http://www.angelfire.com/indie/aerostuff/sae2003n2.htm

Greetings fellow DBF-ers!

I just want to say congratulations to everyone who was part of the DBF competition this year. It was a lot of work, but it was great fun to see all the different teams and check out the many different design philosophies. I hope you all continue with the competition next year as well!

I've been building models for many years, but this was my first time with DBF and it was quite a thrill. I'm a grad student in chemistry, so there were challenges just finding time to get together with the aero guys. Below is a pic of our plane... it might look familiar to some of you.

best regards,
David Fee
SDSU DBF '03

Photo galleries have been uploaded to the AIAA/DBF competition website:
http://www.aae.uiuc.edu/aiaadbf/

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Damn!
No photo ids or thumbnails!
An image number doesn't do it!
Takes waay to long to find there's no information in the image.
Did any of those planes fly?

Hey Paul,
You know, that's a really good point. In previous years they have put captions with the photos so you know what school it is. Hmm. Well, if you give me a filename, I can try to tell you what school it is. I could maybe make a personal page with the top 10 teams or something.

As for how the planes flew, 19 of the 33 teams present posted some sort of flight score. So, a little under 60% flew. I'd say that about half of those flew respectably. There were only about 4 or 5 planes that flew "well."

I hate to say it, but I think pilot skill and experience was a big factor in this competition. Some of the aircraft present could have done better with a different pilot... and others owed much of their success to their pilot.

I saw a lot of pitch stability and control issues. Most of the aircraft had acceptable power, but many of the power systems were rather inefficient. Again, this is probably due mainly to the vast array of experience levels there. I think it probably takes a team 3-4 years to really develop a program and, by the end of that time, the seniors graduate and the team pretty much has to start over.

It was interesting that some of the best looking planes either didn't fly well, or had really bad RAC scores. I really loved the USNA planes... they were very cool but too heavy. One of the planes that impressed me the most was "SWAG" from Mississippi State. The entire plane was made from laser-cut wood parts... and they came to the competition with stacks of pre-cut spare parts! I had to keep from drooling... it was a beautiful thing!

-David

FWIW Here's SDSU in the air.

Unfortunately, I don't have a lot of inflight pics of the other planes because I was quite busy being flight engineer and observer for the pilot. We have video somewhere...

-David

David the SAE planes really don't do much better. Pilotage is the weakest point, with unflyability second.
We provide experienced pilots for the teams that need/want one, and it does make a difference.
The AIAA planes aren't pushing the lifting capacity of the airframe, so the planes -should- be flyable for an average pilot.
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On the photos, 1M images are seriously too large! That's why I prefer thumbnails, to let me select the ones I will not look at.
And it's the airplanes that are the subject, not the people. A team photo is nice, but a few images of the planes.. only the planes.. to see what strange and wonderful items they are...
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My stuff from the 2003 SAE event....
http://www.angelfire.com/indie/aerostuff/sae2003n2.htm
Takes a little time to compose, and sometimes find out which team is which.. but it's better than crap shooting thru an anonymous directory.

They've got thumbs up now, sorted by date.

I agree on the flyability of most entries, though I think the most frightening problems were yaw stability, rather than pitch.

I'm pleased to report that the Belle flew beautifully - handled like a sport plane, except for some really bad manners on takeoff and landing. Those came from moving the CG forward without remounting the landing gear. And she looked great in her new vintage racer paint sceme!

We did have trouble taking off in no wind with our original prop, and had to step up to a bigger, slower one, which sucked more current and flew the plane slower, so we didn't manage to finish the radome mission under the crosswind conditions I got my only good attempt at it under. That, combined with my less than perfect piloting, a surprisingly poor report score, and a run of the *worst* luck imaginable, combined to bring us in at the appropriate position of number 13.

To give you an idea of our luck, on a good run of the radome mission, our battery came *unplugged* in flight. Luckily, even fully loaded, the Belle is a great glider thanks to that flat drag polar, and I managed to make an uneventful dead-stick to the runway.

We'll be taking her back out for some more testing, including the addition of in-flight data acquisition, in preparation for next year's competition.

What david failed to mention is that SDSU took first, in a great up from behind run against Cal Poly SLO. Excellent piloting and engineering made those two teams both stand out.

And I agree, the MSU guys had a great plane this year...

But we're comin' for ya!

Paul,
I stole the pics from the official website and made one with the top 15 teams. I think I got the right pictures with the team names...

Starfire, maybe you can check them for me? Also, there are a couple holes where I didn't know what the plane looked like.

Here it is:
http://members.cox.net/dfee/DBF03%20Teams%201to10.htm

-David

David, that'sa nice..
How many teams opted for the payload drop mission?

Paul,
I'm not sure how many teams actually attempted the payload deployment, but 16 teams posted scores for that mission. 16 teams also posted scores for the "hardest" mission, where the antenna thing had to be carried. Only one team posted a score for the "com repeater" mission where you just flew 4 laps with the package inside. I saw at least one plane deploy their payload on touchdown... which was unintentional. Almost surprisingly, there were no in-flight deployments that I'm aware of.

Starfire,
Thanks for the compliment! It was hard work... SLO was a really tough team to beat!

One of the things that helped us was that our plane was reliable and easy to fly... which meant we could strategize. We calculated that our best chance for improvement was in the package deployment mission, even though it was given a mission difficulty of 1.5 instead of 2 for the com repeater. The deployment mission was more pilot intensive, as it required a good landing in a small area, without wasting too much time making a slow final aproach. Our plane was very fast and we weren't using brakes, so the pilot had to use a lot of skill. I was glad I didn't have to do it!

-David

I had a great time. It was my first year at the competition and I learned a lot.

I was a crew chief for MSU's plane, and I didn't get much rest. Our pilot landed a bit short of the runway on one flight, and the plane hit the grass and violently flipped over, crushing the tail to little pieces. We rushed it back to the pits, and I pieced the tail back together and re-covered it while other team members focused on the nosewheel damage. Every time I'd turn on my covering heat gun, the generators near the tents would sputter and start to die, so I had to shrink the Monokote in short bursts. I was really impressed by how well out team worked together under pressure. It was like we were surgeons operating on a patient, we stayed cool and focused during a very stressful time and everyone on our team did all they could to get our plane back together. We had the plane back in the queue in about an hour, and all of our repairs held up great.

We were plagued with more bad luck on our last flight when our box drop mechanism failed to release the box. The judges couldn't decide if the flight could be scored without dropping the box (while the clock was ticking mind you) so our pilot ignored the judges and just took off again, and luckily on the takeoff roll the box came out! The only time our box drop didn't work was when we needed it most! I'm glad our pilot decided to ignore the judges, as they were eating up our time trying to make a decision.

We scored 8th overall, helped a lot by our assembly time of 9 seconds, which was the fastest at competition, and our report score of 90.

I was impressed by "Spirit of Monty" and I knew it was going to be tough competition when I saw it. Very well done guys, she looks and flies great.

And thanks to Starfire for assisting us in any way that he could at the contest. He's a former MSU student who is now with UIUC, but that didn't stop him from being very helpful to us.

For the most part, the attitudes of the competitors impressed me. Sure, it was competition, but the camraderie between teams was great. When a plane went down, it wasn't like people were celebrating over having less competition. It felt bad to see another school's plane crash and all I saw was respect and support for those who lost their planes.

I hope to see you all next year in Wichita!

Mark,
Allow me to reinforce what you wrote about the teamwork. I thought our team worked really well together, but watching you guys converge on your damaged airplane like a swarm of scalpel-wielding surgeons was an amazing sight!

I also noticed the spirit of mutual support going around between the teams. I think it was really great, and probably due to the fact that one thing we all had in common was the months of sacrifice and pain we'd put in just to get to the competition. I wish I'd brought more props to lend people.

I hope I didn't seem cold at the competition. I don't think we actually spoke, but I was really focused on our plane and making sure all the details were taken care of. I was there to get the job done, although I wish I had taken more time to meet people from the other teams. Maybe next year!

-David

David, this pic is of La Sapienza's #3 entry:
http://www.aae.uiuc.edu/aiaadbf/2003.../im003899.html

I can't find any I recognize for the other two...