Tuesday, March 29, 2011

At Long Last

Finally, Josh got around to buying the cable he needed to upload all our flight videos, so in a moment that I'm sure will have all of you out there on the edge of your seat, here's the flight videos for the UD AIAA DBF team 2010-2011 season so far. First off, videos from the second round of flights with the prototype on March 20th.
Click Here for Flight 1 Video
Click Here for Flight 2 Video
On March 20th, the prototype made two flights, first with a payload of 1.0 lbs, then with a payload of only 0.5 lbs. These was intended to be empty flights, but some tail-heaviness left us in need of nose weight. In fact, on the 0.5 lbs second flight, the reduction in weight left the aircraft very pitchy in flight. However, the propulsion system was finally reaching a configuration that was a bit more in line with the power and duration that we'll need at Tuscon.

Anyway, so that was a week ago. In the past week, we completed and flew V2, our second aircraft. V2 is almost a pound lighter than the prototype (a 20% weight reduction) and reductions in the tail mean that it doesn't have any of the CG issues which plagued the prototype. We managed two flights on Sunday despite the cold on the field. It may look sunny in the videos that follow. It was sunny, but still cold, to the degree that our flight duration on the second flight was constrained not by the plane but by the pilot's fingers getting too cold to keep flying.

Click Here for Video
For the first flight (video link above), we flew empty, the first properly empty flight we've been able to do all year, thanks to the reductions in weight fixing our CG issues with the prototype. Our normal plane-chucker Kramer Doyle wasn't present, so Josh filled in. On its maiden voyage, V2 did incredibly well--good launch, fast as heck, and no hint of the pitch issues that plagued the prototype. Additionally, we discovered that when in the air, the pinkish wings don't look quite so bad--distance and motion blur cures all wounds, apparently.

Josh with V2, Second Flight. Click this Text for Video
Our second flight of the day was a 2.0 lb payload flight--exceeding our original design goal by almost 0.5 lbs. However, even with this, the weight reductions on V2 meant we were still 0.5 lbs below the maximum flight weight from the prototype. Obviously, we had a bit more drama getting into the air this time--as noted, Josh is not our main thrower, and his co-ordination with Chris wasn't quite perfect. However, the result is impressive. This flight had a 35% payload fraction, and if we load the plane to our maximum demonstrated gross weight from the prototype, we'd have gotten a payload fraction of 42%--well in excess of what we were hoping for during the design face. Originally, the fuselage was designed with enough room for about 50% more golf balls than we were designing the wings to lift, for a few reasons too boring to go into. However, it now looks like not only will we fill that volume, but we might have the capability to lift a few more than that!

In the next week, we're going to be putting together the final competition plane, V3. Again, the construction of a third airframe is new to the team's history, and I'm looking forward to further weight trimming. We should also be able to clean up our wing and tail layups a little and get rid of some of the wrinkles we ran into on V2's wings. I have high hopes for V3, and I'm really looking forward to competition.

Sunday, March 27, 2011

Long Hours

This post may not be up to my usual standards, it's very late and I'm tired, but I had a few things I wanted to show off. I spent almost every waking hour today in the wind tunnel, working on something that to my knowledge is unique in the past five years of the UD Aerodesign Team--a second aircraft. After a long week of work, we finally have it flyable, and I have to go to bed soon so I can get up in the morning and go to the field, but I wanted to share some images I took today.

UD Aerodesign Team aircraft, awaiting transport to the field tomorrow
In the image above, the prototype that I showed images of last week is on the right in pieces, ready be packed for transport to the field. The new plane (called V2 because we've been too busy to be creative about names) is assembled on the right. V2 incorporates several lessons learned in the construction of the prototype, and its very existence is owed to some new techniques we've been practicing this year. 

The most critical new technique is the fuselage molding, which we've been doing with assistance in the form of advice and facilities from Industrial Fiberglass Specialties here in Datyon. I talked in my last post here on Engineer in Progress about what a difference this makes in terms of the time and materials, and the plane above is the payoff. Thanks to more experience with the techniques involved in making fuselages from the mold, the new fuselage weighs almost half a pound less than the original, yet still incorporates several structural modifications to reinforce areas that the prototype demonstrated weaknesses in. Making new fuselages is in fact so easy that the fuselage team went ahead and started work on laying up a third fuselage, which will probably be combined with other componetns we have around to produce a third (!) aircraft to our design, with further refinements from the flights and construction of V2.

The really tricky part of V2 was the wings and tail. Normally, we hot-wire cut the wing and tailplane foam cores on a CNC foam-cutter, enabling great accuracy and precise adherence to our designs. However, the construction of V2 was hampered by the fact that the foam-cuter broke between the cutting of wings for V1 and the cutting of wings for V2, requiring that the surfaces instead be hand cut with a wire bow. Josh Nieman, the club president, spent over six hours working to produce the wings and tails for V2, going through an entire 4 foot by 8 foot sheet of 2-inch insulation board in the process. The resulting wings, while not quite up to our normal standards, are still very good, and the implementation of some suggestions from Greg at Industrial Fiberglass enabled us to trim 17% off the weight of the wings by reducing excess epoxy used in our layup--this is demonstrated vividly in the different color of V2's wings compared to V1 as seen below:

Prototype is at the top of the image, V2 at the bottom
V2's wings and tail were laid up using epoxy with the same dye concentration as the prototype. The pinkish tint of V2's wings and the increased visibility of its carbon-fiber reinforcement is due entirely to the reduction in the total amount of epoxy on the wing. The imperfections of the wing are not visible from this angle and distance--the trailing edges are a bit wonky due to cutting difficulties. However, the wings for V3 (which should end up being the competition plane) will be CNC-cut as like the prototype wings were, and thus should have all the improvements of V2's techniques implemented with precision cores like the protoype used.

The testing of new techniques to see what works like with the fuselage and the wings is something we didn't have a chance to do last year, since we only had one plane and one set of wings, and making full use of this ability throughout the plane should make our team more competitive at Tuscon--I know I feel that V2 is a better plane on the whole than the prototype so far. Tomorrow, we find out for sure when V2 (hopefully) makes its first flight attempts, which means for now it's time to get some shut-eye.

Monday, March 21, 2011

Aerodesign Update

I'll admit, I've been putting off posting about the AIAA team. Not because of a lack of things to talk about, but because I've been having trouble laying hands on things to show. Since the last time I posted, the prototype has had about six flights, of varying degrees of success, and we've started working on our follow-up competition aircraft incorporating lessons learned making the prototype. However, video or images of those flights are not on the web yet, except for the rather pathetic maiden flight.

Click Here for Video Link
As Josh notes, the crash was not as bad as it looks, and the plane was flyable again after an hour or two of work. A little experimenting with motors and propellers found a combination that produced power more like we'd been anticipating, and the current setup is much faster and much better in the air. However, as I dais, I don't have any images or video of that I can point to yet. It's been a long time since I did a proper update, so in place of flight highlights, I'm going to post some images of what, in general, we've been up to. More awaits below the cut.

The prototype, nearing completion. Much prettier than last year's plane (TOM) if I do say so myself.

Thursday, March 17, 2011

Missed Chances, Pretty Pictures

Well, the STS-133 flyabout I (and many others) were looking forward to didn't happen. From what I understand, the concept was handed to the Russians for their analysis too close to the mission, and since this was the first flight of a new Soyuz variant, they didn't feel comfortable going forward with the flyabout. It's regrettable that we missed out on the images, but I think the Russians made the right call.

Still, this was a truly historic occasion, even if there were no images. The station had spacecraft on-orbit at the same time from every one of the station partners: NASA's Shuttle, Russian Soyuz and Progress vehicles, the European ATV, and the Japanese HTV. Thus, several people have taken it upon themselves to make sure this station configuration will be remembered. There's so far been one or two great composited images, adding Discovery digitally to the images Discovery took of the station in her own fly-around, but I'm perhaps most impressed by the series of images posted in this thread on NSF. I'm reposting them here only so more people might see them. They are not my work, I'm simply so blown away by the work Keith did I that I want more people to see them. More of Keith's work can be found on his website.

If you recall a post last year when I talked about how long the ISS has taken to finish? Well, the US orbital section (which is a strange name, since it's majority European-built by volume and also includes significant Japanese portions with the Kibo lab) is finally done, leaving the station with only Russian components still left to go up. Even with that left to do, it's pretty impressive:

Wednesday, March 9, 2011

Taking Stock

So, I'm trying to get a better hold on the events of the past few weeks and what it means for this blog. I started Engineer in Progress mostly to serve as a way to put my thoughts on space and my work on the University of Dayton AIAA Design, Build, Fly team on the web in a place where friends, family, and perhaps someday potential employers might see it. Until February, that was basically what was happening. I'd see a few hits a day, mostly people coming to the blog from Google Images.

However, as I've said, in February I saw over 800 hits between links to several of my posts from Winchell Chung's twitter feed and a third party linking to my Only a Model post on NASAspaceflight's forums. Already so far in May I've seen more hits than I did in the entirety of December, and I posted four times then compared to so far none this month. I was fine saying whatever I wanted to an echo chamber, but saying the same to an audience that I don't know but know is out there is a bit more intimidating. I'd like to continue posting updates about UD's AIAA team, I've got some posts about some aerospace ideas that have been percolating, but I'd like to know my audience a bit better.

So, basically, if you've liked what you've seen here on Engineer in Progress, if you're interested in helping me continue to improve this blog, I'd love to hear from you. There's a comments section down below and my email address is now under the "About Me" link in the sidebar. Let me know what posts you've enjoyed or found interesting, others you haven't, and any suggestions for improvement would be appreciated. Thanks for your time, and I'm sorry this post kind of sounds like a PBS pledge drive. Regrettably, I can't offer tote bags or Carl Kassel's voice on your home answering machine, only more posts as compensation for your support. I hope you'll take the time to let me know what you think anyway.