Airfoil - both sides

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wdwkr53
Posts: 41
Joined: Sun Aug 01, 2010 11:13 pm
Model of CNC Machine: 8020 Extrusion

Airfoil - both sides

Post by wdwkr53 »

I'm having problems shaping both sides of an airfoil that is asymmetric. I imported the file with the split into halves option. I machined the top using the top surface of the material as reference. The material thickness is .7 inches thick and the entire part is .6314 inches thick. The top turned out great and the leading/trailing edges are about half the thickness of the material. BUT after I flip the material, if I pick the bottom (which was the top on the first side), it will cut too deep. If I use the top, it may not be accurate if my material thickness isn't exact. Can I reference the .35 inch plane from a SINGLE side (which is about half the thickness) and call that the reference plane for both sides? If so, I can't figure out how. I tried importing as a single body and flipping, but when I tried to machine, it thought the part was 1.2 inches thick. Would a zero plane help here? I'm stuck....
Attachments
bottom half (flipped) with bottom of material for reference
bottom half (flipped) with bottom of material for reference
top half with top of material for reference
top half with top of material for reference

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wdwkr53
Posts: 41
Joined: Sun Aug 01, 2010 11:13 pm
Model of CNC Machine: 8020 Extrusion

Re: Airfoil - both sides

Post by wdwkr53 »

I seem to have answered my own question. I carved the top with ZZero on top of the material. The material setup indicated the gap below would be .3198 inches and the model thickness would be .3802 inches. When I flipped it over for the bottom, it said the profile was .2511 inches and I set the Gap Below Model to the .3802 inches from the first side profile. This referenced nicely and I got a hairline edge on the project. Now I'm ready for the entire wing. I'd better make notes so I can remember this next time it comes up!
Attachments
both sides with Z Zero adjustments
both sides with Z Zero adjustments

sseale
Vectric Apprentice
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Model of CNC Machine: Probotix Nebula
Location: Barbados

Re: Airfoil - both sides

Post by sseale »

Thanks for sharing - Taking notes on this also for future plans with cutting hydrofoil cores on the cnc.

As far as using 2d toolpaths - I was thinking of using the moulding toolpath and split NACA foil section as the profile vectors for top and bottom surfaces. The common z references being the leading and trailing edges. Might be limiting in that no wing sweep/taper available, maybe two rail sweep would be better for generating wing shapes with varying aspect ratios/taper etc
Scott

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wdwkr53
Posts: 41
Joined: Sun Aug 01, 2010 11:13 pm
Model of CNC Machine: 8020 Extrusion

Re: Airfoil - both sides

Post by wdwkr53 »

I did the profile this AM and it turned out great. It is so thin on the edge that you can see through the material left - which is what I wanted (.040"). I hope this can help someone else in the same situation.
Attachments
entire wing one side
entire wing one side
Very thin edges
Very thin edges

armbrusterco
Vectric Craftsman
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Model of CNC Machine: Roland MDX-40A
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Re: Airfoil - both sides

Post by armbrusterco »

Thanks for explaining how you did this. I will be making some rudders and keel fins for rc model yachts.

Bob
Bob Armbruster
www.ArmbrusterCo.com

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