Structural Build Advice

[AfterBurners]

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]

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..

 

[Daddyisabar]

I would like to see the design but flying a 4" diameter jet on composite motors will take a light ply of some sort for flight and landing stress.

 

[rstaff3]

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]

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]

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]

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.