|Jan 07, 2010, 07:17 PM|
Gah, I didn't even mention my Ultrafly Furious in my last post. I'll have to get back to that one. -But in the meantime, I wanted to post up some thoughts about my latest plane, the Mini Speedwing!
Fun little plane!!!! This is my first delta wing, so it's been a big learning curve to fly well. Flying wings don't fly like anything else, so you have to really feel them out.
So I spent a lot of time researching setups for it, and to be safe, I built it almost exactly how they prescribe in the instructions. The biggest decision for me was the motor. I had read about how to build it using a brushless outrunner, and was tempted to go that route, but eventually decided to play it safe for my first delta wing.
Feigao Brushless motor 1208436L. I was seriously considering going with the Feigao 1208428L motor which is essentially the same motor with 28 stator windings instead of 36, resulting in a "hotter" motor that spins faster, and has less overall electrical resistance. (Disadvantage being higher amp draw and heat loads.) The thrust specs are much stronger for the weight, but I decided to stick with what they recommended. Hindsight, I still don't know which would be better... The 436 motor seems to have a descent amount of power on 2 cells (yet won't go vertical or anything), but still seems to get rather warm flying on 2 cells. I'm kinda scared to find out how hot the 428 would have been, especially if I upgrade to 3 cells like I plan...
Spektrum AR6100e micro receiver
(2) Hitec HS-55 micro servos
Cheapo 12 amp ESC (in the shop)
Cheapo 2-cell 1000 mah LiPo batteries (in the shop; will likely go to 3 cells when I feel I have mastered the plane)
I also covered the plane with black Ultracote, using 3M 77 spray glue. Turned out great, looked like a freaking stealth bomber. Turned out to be hell on the orientation though. (The wings are hard enough to keep orientation on, and with the whole thing black, I was completely messed up.) I had to add some more colors and stickers to it. Ultimately, I also added bigger side winglets to it with a much more distinctive profile, so I could keep orientation from the side.
For the battery, I just velcro-ed it onto the bottom of the wing instead of burrowing a large battery compartment into the wing. Opinions vary on which is better, but this was the quickest and easiest to do for now. -And it flies great like this, so I'm not going to mess with it right now. I'll probably cut out an area eventually, but I want to try 3 cells first and settle on exactly what battery I want to use first before I go cutting on the fuselage.
The learning curve behind flying a delta wing is kinda steep. The hardest thing about it is learning how to properly launch it... After several attempts and methods, I am the biggest fan of the following:
1) Hold the plane by the wing with your dominant hand, (controller in other hand, obviously)
2) Full throttle
3) Give it a genital toss, almost like throwing a frisbee, but with much less emphasis on rotation, about 30 degrees above the horizon.
4) Get your hands back on the controller as fast as you can!
I'd recommend having someone else toss it for you the first couple times, until you get it trimmed out and start getting used to the airplane. It always goes a little squirrely the first 100 yards or so, so you need to get on the stick to keep it from crashing.
One thing you need to remember is delta wings don't have tail wings, so they are inherently unstable compared to airplanes you are used to flying. The key: LOTS OF EXPO! These delta wings are really touchy, and adding exponential is your best friend.
It doesn't loop very well, but OH MY GOD does this thing spin. In fact, I've never had an airplane that spins as fast as this thing does. Too much fun.
It's not quite as fast as I'd thought it would be. I was thinking it would be upwards of 50 mph, but it really doesn't seem to be that fast to me, even after I upgraded from the 3x2 to the 3x3 prop. It probably goes more like 35 mph on full throttle, but with some pretty insane speed during dives. (Nothing dives like a delta wing, hehe.) It's plenty fast though, especially considering it's only 24" wide.
One kinda annoying feature of delta wings though, is elevator trim. Partially a product of no tail wings, the delta wing "rides" on the elevator a lot more than other planes. I find that I always have to trim elevator, depending on what throttle I am flying at. Typically I just keep it trimmed for about 80% throttle If I want to fly slower I have to trim as necessary, (usually 2-3 clicks down to 40%, which approaches stall speed) and then just control elevator as necessary when I do 100% bursts.
Overall, a fun plane though, and a good introduction into delta wings.
Well, I've been flying my Mini Speedwing at every opportunity for several weekends now, and I wanted to add a few things about my Mini Speedwing.
In hindsite, I think I'd have been much better off with a faster setup than what they recommend. As my first wing, I built the Mini Speedwing without any idea of exactly what to expect, but one think I've learned is that there seems to be basically two ways to build/fly delta wings:
A) Blinding Speed. -Pretty much what most (at least IMO) have come to expect from delta wings. Lots of power, 2-3 minute flight times, and a partridge in a pear tree.
B) Slow(er), light, floaty, more acrobatic wings. -Which is what the recommended power system for the Mini Speedwing is, apparently.
Unfortunately it seems to me that "longer" delta wing designs with more surface area (like maybe the Mini Swift?) are a bit better for the "light and floaty" in mind than the traditional wings, like the "Speedwing" designs. My Mini Speedwing is decently stable at the slower speeds my motor provides, and I have a good time with it. But I find it has far too many bad habits when I slow it down and try to float it. If I really want to "float" around and do acrobatics, I find that I get a lot more enjoyment (and flight stability) out of my 3D plane. The unfortunate reality is as you approach stall speed, you have to "ride" on prop power more and more, and when doing that, "pusher" designs like delta wings have a major stability disadvantage to "puller" designs like 3D planes.
To me, the real fun of the Speedwing is, well, speed. (what a shocker, lol) For Speedwings (and all Delta Wings for that matter), going full throttle in a dive, and pulling up hard for a full vertical corkscrew is where the real strength is, and in that regard, the recommended power system I put in this Mini Speedwing is definitely lacking.
|Sep 07, 2011, 07:55 PM|
I know this is an old thread...
I recently built a mini speed wing and used a feigao 1208428L that I had on hand and wow! It rocks! I don't know what the unload amp draw is in the air, but the bench testing with a 3x3 is over driving the motor. Throttle management is a must. That said it, it moves. My mini speed wind is a bit heavy at 221 grams with a KyPOM 850mAh 2 cell attached. I used carbon fiber to stiffen the wing and it is stiff.
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