Structural Build Advice

AfterBurners

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I'm planning on doing an upscale of a jet. It will be 4" diameter and of course have some lumber on it. Do to the fact that I would like to keep it lite. I'm thinking about going with balsa and gluing hard wood to the leading edges of the wings and stabilizer(s) The reason I decided to go with balsa over ply is because balsa would be much easier to work with when it comes time to airfoil the pieces.

I plan on using a 38mm with a slim line retainer in the tail cone to make it more realistic. Can I get away with flying something like this on 38 with surface mounted balsa pieces or should I rethink the design and try to fabricate TTWF design? I mean I could always fly it on a 29 with an adapter, but what fun is that?

I'm even debating skinning the fins and wings, but I want a nice finish with the wood and I like the smell of the dope! :lol::lol::lol::lol::lol:

Thanks guys!
 

dr wogz

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Depends on the size of the wing surfaces. Sheeting them greatly helps, and you can get ply in 1/32" and 1/64"! You also might get away with glassing them (1oz cloth for instance), or even a layer of Carbon fiber sheet top & bottom..

Also depend how fast you expect this thing to go!

You also might want to split the "wing" balsa into two or three parts, and have a hardwood spar (or maybe two, or three) spanning the length (wing tip to wing tip). Or even go with a 'truss' type internal structure.

You might also want to do the traditional 'Ribs & Spars" build as is traditional in plane wings, with full sheeting. And even use "Monokote" (or Ultracote, my preference) as your finish.. Dunno how thick you intend to make the wings..
 

rstaff3

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I have flown H motors on craft store foamboard framed with hardwood. As with other materials/techniques, they held up better on boost than on landing.YMMV.

I agree completely with the good doctor it his post above.
 

AfterBurners

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I was thinking about using hardwood around the leading edges and tips of the horizontal and vertical stabilizers. 1/4" balsa and 1/4" hardwood. Like I said I want to use the balsa for weight purposes and it shaping the airfoils would be a lot easier.
 

Handeman

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I have a 38mm 3" rocket I use TTW fins on and just glued 1/4" thick balsa sheets to the fins and used a hand sander to airfoil them later. These happened to be 1/4" ply fins with a 1/4" of balsa on each side. The fins are strong and have held up well through 25 flights so far on H to J motors. The leading edges are the shaped ply so no hardwood was needed.
 

AfterBurners

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I have a 38mm 3" rocket I use TTW fins on and just glued 1/4" thick balsa sheets to the fins and used a hand sander to airfoil them later. These happened to be 1/4" ply fins with a 1/4" of balsa on each side. The fins are strong and have held up well through 25 flights so far on H to J motors. The leading edges are the shaped ply so no hardwood was needed.

Hopefully with this build I can do ttw fins. I haven't worked on that part of the design.
 
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