Help creating a 3D model of a hotwire cut airfoil.

[GreenAce92]

Hello All,

I developed this aircraft as a proof of concept of an Ultralight that I designed. I wanted to create plans for it so that others may build it as well. I am having troubles figuring out how to create the airfoil you see it isn't simply a "draw airfoil - extrude - scale other end".

The way this airfoil is produced is by taking two templates, one for the root chord of the wing ( center ) and one for the tip chord of the wing ( wing tips ). Then by use of a hotwire cutter, the airfoil is created by basically tangential cutting, so you see, by using a blend of both a washout of 2 degrees and a 0 degree incidence airfoil, you get a twisting "washout" effect.

I don't know how to make something like this in sketchup, can someone help me out?

Here are the airfoils which I drew myself.

[sdmitch]

The main wing can be created in the same manner as I created this tail section.

[GreenAce92]

Hello Sam,

I watched your video. Unfortunately my wing is not as simple as your wing.

If you imagine the two templates above spaced 18" from each other, then a hot wire traces these two shapes, you can see how this shape is not something that can just be made by "scaling" one side, it is a shape that changes across the entire span of the wing.

One method I can think of is to cut sections from the wings and then trace those sections, align them and join them with the "draw-sandbox" tool but that defeats the purpose of designing since that would require a product that already exists to be reverse-designed into a CAD model.

I appreciate the response however.

Is it not possible to have two different shapes, then some sort of command creates a solid object as if a skin was rolled around these objects? Take an ellipse and a square then create a skin that joins these two shapes into a vase like structure.

[Gaieus]

Here is a method using only native SU tools (Arc, PushPull and Scale)

[mac1]

AIRFOIL.skp

Take a look at Fredos curviloft tool. The attached used your info above, F spline fit to those, set scale of bottom to the 3" ref, did not set 2" of the top, 18 " separation. There are question about the station and position relation. Curves need clean up or provide x.y.z and station info.

[mitcorb]

@Gaieus:
That video has trouble starting.

[mac1]

Did for me also but it did run>

[mitcorb]

Well, it's an oldie but a goodie. I remember it when I hopped on at SU v6.