Undercanbered wings

jrb53

Say you want to do a Nieuport 17 wing:  http://img.photobucket.com/albums/v204/FlyXwire/Nie17_Rib_Study.jpg  This appears to be basically symmetrical along the bottom.

Wing plank of say 2" by 12".  Take  a piece of 12" long PVC of 2" diameter.  Steam the wood plank so hot that you need gloves to hold it.  Put it inside the pipe.  Now quickly drive a 12" length of 1 1/4" pipe inside.  That plank has to bend, or if its not steamed enough, it going to break.  This could be a case where basswood may not be the best choice for wing building.  White oak, hickory and birch are well known for their flexibility.

Once cooled, the plank can be worked back-and-forth against a belt sander (like shaping a knifeblade) to achieve the proper rounding or thinning.

Just a few thoughts,

Jack

Okay, that is a different method. I had made a blank for lower surface with lower surface airfoil.  I wet the laminations in hot water, and wrapped cloth strips around the assembly.  Problem is, I did not use enough strips, wood buckled up between strips.  Your method holds down entire length to form.

Only problem I see is that result is circular airfoil, with high camber at half chord.  That may be okay for bottom airfoil- the top is much more visible and as long as I carve the proper one on top, the exact shape of bottom is not likely to be noticable.  So it is worth a try.  Thanks.

Say you want to do a Nieuport 17 wing:  http://img.photobucket.com/albums/v204/FlyXwire/Nie17_Rib_Study.jpg  This appears to be basically symmetrical along the bottom.

Wing plank of say 2" by 12".  Take  a piece of 12" long PVC of 2" diameter.  Steam the wood plank so hot that you need gloves to hold it.  Put it inside the pipe.  Now quickly drive a 12" length of 1 1/4" pipe inside.  That plank has to bend, or if its not steamed enough, it going to break.  This could be a case where basswood may not be the best choice for wing building.  White oak, hickory and birch are well known for their flexibility.

Once cooled, the plank can be worked back-and-forth against a belt sander (like shaping a knifeblade) to achieve the proper rounding or thinning.

Just a few thoughts,

Jack

What size wood are we talking about?  2" wide by 12 " or 14" long? and does the camber need to be asymmetrical or could that be shaped afterwards by sanding? (OK,  so I'll be researching WW1 airfoils tonight!)

And when you laminated, did you glue the planks together, let dry and then attempt to bend? or did you glue and immediately place it in the bending jig?  One way would seem to be fighting the glue, while the other would let the glue assist and maintain the bend.

I apologize for the questions Don, but you've triggered the "scratchbuilding juices"

Jack

jrb53

I don't know how thick your blank is, but I would be tempted to try wetting the wood plank and warping it in a jig, maybe a PVC pipe-within-a -pipe jig, or just weighting the edge to make it bend..  Sort of using the old  "steamed wood" approach to get the proper bends.  Then you could round the leading edge and taper the trailing?

Jack

I have tried that. I laminated the blank from three pieces of 1/32 basswood. It came out quite wavy, but I still think the idea has merit and may try it again.  I recently did a Pietenpol wing that had only a small amount of undercamber and a fairly thick section.  That worked fine sanding the undercamber in, but when I do another WW1 model, very thin sections, I think I will try the laminated-over-form method again. I think I need more wrapping to prevent the waviness.

I don't know how thick your blank is, but I would be tempted to try wetting the wood plank and warping it in a jig, maybe a PVC pipe-within-a -pipe jig, or just weighting the edge to make it bend..  Sort of using the old  "steamed wood" approach to get the proper bends.  Then you could round the leading edge and taper the trailing?

Jack

I agree with you about the cutting of the ribs, takes a while to do right. Then you think you're done & realiz that your knife actually had some angle to it, which will throw off the angles when you start assembling things... hmmmm, laser cut??? That would be worth looking into.

I'm actually surprised at how light+strong the basswood that I'm using is. You probably could make solid wing sections out of it without too much trouble, although sanding it - you don't get sawdust so much as, uhhh, fuzz, or lint. You'd probably be advised to wear a mask!

VanceCrozier

Well Don, I'm not a regular scratchbuilder by any means, but I've had to re-think how I approach my first scratchbuild project - a Horten 229 flying wing. Fairly simple shape, I was planning on cutting the appropriate ribs from basswood, stringing them together, then skinning with sheet styrene. I can't get the things to stay aligned, so I've modified my plan.

I'm drawing the top silhouette on thin sheet styrene, then splitting the ribs into top & bottom halves. These (should) then be glued to the silhouette in the proper places. The styrene will also provide an area to use for  bracing the ribs as needed. Maybe this process can be used for your wing portions as well? Any other thoughts on what I'm trying would be greatly appreciated!

I hate the repetitious task of cutting out all those ribs.  I really like the new flying model kits with laser cut ribs.  I know there are now laser cutting services that will cut ribs for me if I do the drawing in the proper format, but the number of ribs needed is what leads me to make solid wings.  I guess if I covered the wings with tissue I would not need to do the simulated rib stitch pinking tape, but that doesn't really take that long anyway.  I guess I will have to look into these laser-cutting places.  Anyone here use one of them?

Well Don, I'm not a regular scratchbuilder by any means, but I've had to re-think how I approach my first scratchbuild project - a Horten 229 flying wing. Fairly simple shape, I was planning on cutting the appropriate ribs from basswood, stringing them together, then skinning with sheet styrene. I can't get the things to stay aligned, so I've modified my plan.

I'm drawing the top silhouette on thin sheet styrene, then splitting the ribs into top & bottom halves. These (should) then be glued to the silhouette in the proper places. The styrene will also provide an area to use for  bracing the ribs as needed. Maybe this process can be used for your wing portions as well? Any other thoughts on what I'm trying would be greatly appreciated!