Can't thicken a loft (building a wing) - file attached

[kim.volz]

I have reviewed the "create Solids from Surfaces and even tried the "solved solution of thickening a loft".  I've tried numerous different ways to create and simplify the airfoils, but nothing seems to provide a thickened part.  Including redrawing everything with "Control Point Spline".

I can reverse engineer based on the timeline if someone actual is able to accomplish the task...

I have created a very simple wing and provided the ribs for the outside and inside shape.  How do I create a thickened skin?  

[jhackney1972]

Your small wing profile has some real problems in the front and since you brought it into the model, it cannot be edited.  I cleaned it up using the Mesh Section Sketch tool to get a Lofted surface.  The trailing edge is so small, I can then on thicken it to 0.5mm.  You may be able to get a little more but I go tired of trying different values.  Mode is attached, such as it is.

[kim.volz]

Hello John,

Thanks for taking a look.  I wasn't able to determine what you actually did so...

I'm using the scripts & add-ins of the "Airfoil_dat_to_Spline_v20 and I saw in other tutorials.  I pulled in an airfoil and started to try and make a wing.  Obviously, I wasn't able to make that happen.  The trailing edge doesn't have to be that thin and I expect it to be around 4mm thick.  I was going to make this as my next steps, so maybe I have the wrong order of making the wing.

I know I'm asking a lot, but if you could make a video like you did to loft and thicken a wing, that would be GREAT.  If not, I understand and will continue my journey using mock-ups to get things right.

Thanks for the help you provided!!

Sincerely,

Kim

[TrippyLighting · Accepted solution]

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@kim.volz wrote:

I'm using the scripts & add-ins of the "Airfoil_dat_to_Spline_v20 and I saw in other tutorials. 

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Yep, that unfortunately never gets old 😕

Sometimes it works and then some well meaning folks make tutorials including workflows that are not reliable.

A spline follows very specific mathematical rules. The spline most people use is a fit point spline, which in Fusion 360 is a 5-degree multi span spline. This is quite a complex mathematical construct and also uses proprietary algorithms that don't translate across applications (as opposed to a control point spline).

The algorithm that calculates the points for an airfoil also follows some mathematical rules, but those are distinctly different rules than those of a fit point spline. If you try to fit a spline through those points, sometimes that results in bad curvature problems as errors compound and that often results in these loft/shell/thickening problems.

Often the best approach is to use the imported points as a visual guide and use a control point spline to approximate the curve. I'd start with one 5-degree control point spline with 6 points (which makes it a single span spline) each for the top and bottom curve.

[kim.volz · Accepted solution]

OK, I got it!! I followed your suggestion and brought in the airfoil and then "traced" it with "Control Point Spline". After a couple of tries, to know where to stop and start the spline, I was able to get a skin with thickness. For others, realize that you will have to make the spline the INSIDE edge of the object and thicken to the outside, at least that's what I had to do.

Thanks for the background details, it all made sense after that.