I have designed my own flying wing and had it cut from flyingfoam. I would love the input of some of the members of DIYDRONES. The span is 60", I chose an MH60 airfoil and added about 2 deg washout. I cutout the motor mount and servo mounts on my CNC router. I'm turning an 850kv motor rated at something like 100w with a 10x4.7. (I'm gonna burn it out at this rate, but oh well, it was cheap.) Flies great on 3 cells. Its a rocket ship on 4S.
I've found the CG to be super finicky, only about a .375" range that it flies acceptable in, at about 15% MAC. Notice in the picture I running a monster 5Ah 3s. This is what I had laying around, I think its a little to big. I think a 2Ah 3S pack would be better weight wise. Because its nose heavy I have huge control throws. If I'm not careful when I get slow and start turning its easy to find myself in a semi-stalled over banking situation. The only way to break that is to let up on the back pressure and apply a lot of opposite aileron. It does have a tendency to spin if I sit on the elevator full aft. I think this is because I have insufficient washout and giant elevons at the tips to compensate for the CG.
Hand launching is a breeze, just give it a little throw while holding onto the battery pack. Landing is an easy affair. It will fly inverted, rolls are not dialed in yet, still messing with differential.
I would love anyones input on the stall characteristics or anything else regarding this bird When I've learned what I can from this I am going to order up a new set of cores with whatever changes I think are necessary, probably more washout, and maybe tips cut with a little toe in.
Eventually I want to put my Ardupilot 2.5 recessed into the foam with an FPV setup. Just ordered my goggles!
Anyone interested in having me cut them anything custom on my CNC router, I've got a 24"x36" CNC router setup. I am tooled mostly for composites like carbon fiber and G10/FR4, but can cut most anything. I'd love to help out the community here with a reasonable CNC service. Send me a PM.
I made my motor mount way to big. I'm going to make a low profile one.
I just glued the servo mount down with thick CA. My z-bend sucks, I know. The control horn goes all the way through the elevon and is glued in with CA.
Comments
@andrew
I liked the swept forward model design better but i cant argue with that lovely streamlined wing.Would love one.
@exaustgas
I found a site Here before that had a large range of airfoils for wings and tail-less specifically.
I used one (cant remember which) on a wing and plane.From testing of the plane,it sure lifted a lot of weight.Around 3-400 grams easy.
sorry for the long response, I totally missed your post!
Revision 1: Currently flying, flies well. Stalls at the tip first however. Very little pitch trim change with airspeed. During slow high bank turns it has a pretty good overbanking tendency. Flies inverted, not great.
Can you open an autocad file?
revision one CAD file
root chord: 14.22"
tip chord: 6"
sweep as distance 17.9"
cg location: 15% mac
washout: 1.6 deg
semispan: 30"
Revision two: In construction, much bigger. Here is the link to the CAD file for number two. I have very high hopes for this one. 2 deg washout this time. MH60 root, MH 91 tip.
revision 2 cad file
I can't wait to hear what your program says about these wings!
You have a cool looking wing, how'd you make the images? How will it land?
Ted
I just added a photo album of my most recent thinking on the topic of flying wings.
<br /><small><a href="http://www.diydrones.com/photo/photo">Find more photos like this on <em>DIY Drones</em></a></small><br />
I'm still following! :) After playing around some more in XFLR5 with my own wing project (still theoretical...) I'd love to get the geometry data you have flown and see what I can make of it using XFLR5. Can you post me tip chord, root chord, semispan, tip LE setback, washout, CoG position so that I can do some simulations?
So everyone still following:
In order to make the wing more suitable as an FPV plane the redesign is going to have the following significant aerodynamic changes (would love the input here)
Any ideas on making this a better FPV platform? I think I'd like to increase the wing area by a about 30% as well for weight bearing capacity, but even at about 2 lbs this thing really bounces around in the wind.
@ exaustgas I Went and had a look at that site docstoc and got pissed off at them trying to charge - so did a big hunt around and have found a copy of that document for you - I have sent you a friend request so you can PM me your email address.
I don't think I can attach it to this message - I have had a look and can't find anywhere.
you don't happen to have a copy of this document yourself you could email me do you, this site is trying to extract money from me...
You are definitely going in the right direction with your comments on the wider cord and different foil at the tip. I found my starting point was a little "off" based on some Reynolds number analysis, and ended up making those design change early on. You have to start somewhere, then refine. You might find this document a good read:
DESIGN PROCEDURE FOR FLYING WING R/C MODEL AIRCRAFT WITHOUT ANY VERTICAL STABILISATION AID (NO FIN, NO RUDDER, NO WINGLET)
BY JOCHEN HAAS
http://www.docstoc.com/docs/25337832/DESIGN-PROCEDURE-FOR-A-FLYING-...
Keep us posted on your progress!
Hi Andy,
I used the information found on this site to estimate washout, I however did not follow the advice. I wish I had. Thats OK though, now I have a base point of learning. A little reflex will take care of not enough washout. Don't get too bent out of shape on washout, it will probably still fly fine. I believe it called for 3 degrees or so, but that just felt like too much, so I settled on less from a gut feeling. I think my wing needs either another degree or so, a wider chord at the tip, or a different foil at the tip. My next wing will probably have a symmetrical tip foil that is negative slightly. Also, I don't think it is necessarily prudent to have the elevons span the whole trailing edge. I think it only needs to go from the MAC to the tip, but I have no references for that other than my own drawings. I am going to cut out a few wings from pink foam and make a few gliders to test some theories. I think with a properly designed wing you can bring the CG way aft and still be stable. Its really all a balance act between the CG and CP. Also, I don't think winglets are required. But they must help.
I learn by trying things, Ill post my findings here.
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