Dollar Tree Foam DLG (proof of concept)

by ESS075 | August 3, 2013 | (4) Posted in Projects

I had never flown a DLG but they looked like fun so I ordered an inexpensive one to try out and crashed it the first day simply because of learning to launch and fly. I decided it was time for a really inexpensive DLG for learning. The question was, would Dollar Tree foam board handle the launches?

 

 I decided to start with a 48 inch wingspan, and built the wing in a manner similar to Bloody Wonder and Baby Blender. The only difference was I made it in two 24 inch halves and overlapped spar halves in the middle for extra strength. I also wrapped the spar on the left end with three wraps of packing tape for extra strength for the dowell.

The final decision was how to make the boom. Since I am also an Archer, old arrow shafts just happen to be lying around the house, however, I think you could make a foam boom similar to my arrow shaft mount. To attach the boom to the wing I made a square of foam with the inside a fairly tight fit for the arrow shaft.

 

Then I cut a 4 inch piece, hot glued the shaft into the foam and then later glued the foam to the underside of the wing. I also needed a way to attach horizontal and vertical stabilizers. So I also cut and glued two two inch pieces to the opposite end of the boom. I glued all three pieces to the boom at the same time which insured that the stabilizers would be lined up correctly.

 In the photo you can see the two extra layers of foam board to raise the horizontal stab. Both Stabs were cut using an existing DLG as a model. This plane only had an elevator and ailerons. Finally for the fuselage. This is just a box with a rectangular cross section. I have it sticking out 11 inches in front of the wing. I wanted to be sure that I could balance the plane by moving the battery and reciever and would not have to add any weight.

 

The final question, is would it survive a launch, and would it fly. It survived about 20 launches starting with easy launches and working up to throwing as hard as possible. Flight was ok but not great. We could get it about 30 feet in the air and circle it around once and land it. It does not have the lift of a decent DLG, but it did its job. My son and I can both throw and fly a DLG, and we learned without spending a fortune for a plane.

I think I can increase lift without adding much weight by going to a 60 in two piece wing, or even up to a 72 in three piece wing. This should make it glide better, but that will have to wait until version 2. I also think that if you do not have a carbon arrow shaft handy, you could make the boom out of the foam the same way I made the square tube for mounting my boom.

COMMENTS

rcspaceflight on August 11, 2013
It might not be a manner of not enough lift, but rather too much drag. Sanding/dulling the sharp edges might create a noticeable difference in air time. Also making the rough surface of the foamboard smoother with paint or tape might make a noticeable difference.

But it does look like a great plane and I agree that the point of a foamboard DLG is for a cheap practice plane. There really is no way to build one as great as the expensive DLGs. But they can still be fun and more importantly, cheap fun. :D
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baconflyer on August 12, 2013
nice job! I tried the same thing (and posted an article) and my dlg looked quite similar to yours, but with a 60 inch wingspan. the main problem with mine was that I couldn't get my hands on a carbon rod for the boom, so I ended up using a bunch of bits of balsa glued together to make the tailboom xD. by the way, definitely add more wingspan. also, rather than doing the flitetest trick of making a bunch of creases in the upper wing surface to create the aerofoil (which has lots of little ridges and therefore much less efficiency) it's better to just take the paper off the inside of the upper wing surface, then allow it to curve over in one fluid bend.
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rcspaceflight on August 13, 2013
I thought about trying to build a DLG out of Adam's foam board. I was going to remove the paper from the top and bottom of the wing and try to create a nice smooth, thin wing without a flat bottom, but rather an undercambered wing. I want to use some sort of glue to make it rigid and to hold the shape, I just don't know what. Hopefully I won't have to fiber glass it because that is beyond my ability, plus it would increase the price too much. Any thoughts?
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ESS075 on August 30, 2013
I am going to try a modified Armin Wing next. I think if you remove the paper from one side, and cover it with packing tape you should have the strength to pull it off.

On another note, I am really bothered by my arrow shaft. It works great, but is it really a foam DLG? My next version will be 100% adams foam board. I have been working with some new techniques and am hopeful that my next foam DLG will be all foam. Any comments on adding dihedral? Do you think it is necessary? Would it be nice to have?
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rcspaceflight on August 30, 2013
Actually, last night I test glided a quick "DLG" I built out of busted "DLG"s that I tried/built and I had dihedral on that one. I think dihedral would be a huge benifit. You don't need it, but you might lose too much altitude trying to constantly correct the plane.

I agree with you about the arrow shafts. Today I just tried a new method of making a foam tube and the foam tube is a few grams lighter than my aluminum arrow shaft. It definitly isn't as strong and isn't worth what I gain in lightness, but it would be nice to be all foam. (And packing tape, and hot glue, and bamboo skewers.)

I don't think what I'm building is going to actually be a DLG, but it will be a really light glider. I just think it'll be too weak.

Good luck with your DLG. It sounds like you're on the right track.
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Kurt0326 on December 18, 2014
Remember what Bixler always said, "...making planes out of common things you can find around." So you are still in the spirit of Flite Test. I think anyone can find an arrow shaft, or a thin rod some where. So don't get hung up on being completely foam board. Great job!
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baconflyer on August 12, 2013
if you want to take any ideas from my build go ahead, it's an article on here. just search "foamboard dlg v1" and you'll probably find it. keep working on yours! we need to show people that you don't need hundreds of dollars of fiberglass and carbon to make a dlg.
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28th St. Air on August 12, 2013
Some good ideas here. I like the offset rudder. I never even thought of doing that before out of narrow thinking. Have you considered an Armin wing design from Ed at exairlines? With a 60 inch wing (5" wing cord) and a couple 30" arrow shafts spanning the wing, you might get the beef in the wing needed for hard launches, plus the lift and added aerodynamics needed to keep it in the air longer.
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Dollar Tree Foam DLG (proof of concept)