Replies to This Discussion

3D RoboticsPermalink Reply by Chris Anderson on February 21, 2011 at 9:16pm

Looks good. Are those spoilers at the top? You're thinking balsa-planked foam?

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Permalink Reply by Jeff on February 21, 2011 at 9:26pm

Yeah, that was my first thought was balsa covered foam, wasn't sure how rib/spar would handle with this design. Was thinking it would get kind of messy and foam is easier to remove and for the balsa covering over fiberglass I just see it as cleaner and easier to get a good finish on with all the moving parts involved (and less mess/hassle). Yes that is a spoiler, this is as close as I could come to the oblique wing on a X-47B. Wing tip is not made/on yet, that would have given it away haha.

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Permalink Reply by NerdyFirefighter on February 21, 2011 at 9:31pm

Looks good.   Have you thought about throwing this in FloWorks to see what your spoiler kicks up?   It would be a good way to estimate loading as well...

 

 

Let me know if you want some quick and dirty analysis :)

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Permalink Reply by Jeff on February 21, 2011 at 9:35pm

I actually am going to do some CFD analysis on it using Ansys Fluent when I get the chance, with midterms and loads of homework this week it's been hard enough with just modeling, but yes I do plan on doing some CFD with it.

It's also a possibility if by the fall I have a model prepared I could most likely get it in a wind tunnel here at Michigan. That would be the ultimate goal after what optimization I can do but who knows.

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Permalink Reply by NerdyFirefighter on February 21, 2011 at 9:40pm

Good man.

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Permalink Reply by Bryndang on March 29, 2011 at 12:56pm

from the building standpoint it should be pretty straightforward.  the hardest part, IMO would be getting the hinges to work for the spoilers without hitting on the surrounding material, but that shouldnt be too bad.

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Permalink Reply by Russell B. Sutton on April 14, 2011 at 5:32pm

Not hard at all.  My dad and I did this when I was a kid many times.  Pick an airfoil, design the wings, Cut out airfoil in the foam with hot wire, cut out servo pockets for the Flaps, Spoilers, Alerions, wiring and front and rear spars.  Align and epoxy sections together.  Then comes the messy part.  Start with one side lay your Kevlar or fiberglass then your thin Burch sheeting then flip and repeat.  Next get it in the vaccum bag and let set over night, and dont forget the mold release.  This all only works well if you vaccum bag the wings.  12 to 24 hrs later remove from the bags, trim, wet sand to 1000 grit clean up and install servos.  I have watched my dad cartroll a 12ft wingspan gilder along the ground a few times and all it would do is bend the steel wingspar insert shaft.  Install new steel shaft clean it up and go fly again.  All of our plane were kevlar not fiberglass,  Very very strong and light. 

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Permalink Reply by Jeff on October 2, 2011 at 8:35pm

Did some more modelling in Solid Works over the weekend and this is what I came up with (still missing wingtips). Very primitive with no mechanical devices added, figured they could be implemented when it was a solid. Just a start though on the whole plane and what it would look like as a solid. Was mostly looking for something that could be CNC'd or cut on a router. (The top scoop is a separate part than the fuse)

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Permalink Reply by UAVOZ on October 8, 2011 at 12:03am

I am going to use Solid Work to make my UAV too. got a 4x4m CNC built by my brother ready but still need the right model to start with. I started from zero so need a bit of time to learn.  Also still decide what type of material for the UAV.

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Permalink Reply by Richard Unwin on October 9, 2011 at 9:45pm

i like the fact that you are thinking ahead and planning what will happen when you try and make the wing. the reality of bringing a design into life exactly as you designed it on 3d computer is sometimes very hard.

 

I have been having fun trying vacuum bagging wings and found it to be quite easy to get good results and makes for a light and very strong wing. the hardest part is working out the method of hinging your control surfaces.

 

also the best hint i can give if you want to have a go is start with a 5:1 epoxy resin, it is easy to mix in the correct ratio, gives a good working time to get every thing in the bag and positioned, is not smelly like a polyester resin (dont want to upset the wife and die of fumes) and while being more expensive is easier to get good results the first time. My first few tries with polyester resins didnt set in the bag and so I wasted the whole setup and had to start again.

 

I would also suggest just getting blocks of foam roughly cut into a wing shape (small sections) and then giving it a go, after 1 or two goes then have a go at trying a full size wing.

If you want any ideas about wing bagging let me know. although this and other sites have heaps of How To's on wing bagging so look some up. 

 

richie

 

 

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Permalink Reply by Jeff on October 10, 2011 at 11:18am

I have a friend that makes scale models and has about 5 made already of WWII aircraft he suggested I take the 2 outer wing portions and hot wire them and then make a "box" in the center where the propulsion is and have the main structure there. In that case I can have spare wings/nose cones available in case of a "hard landing" ;).

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Permalink Reply by Bryndang on October 10, 2011 at 11:19am

lets see some pictures!

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