Creating the correct profile for a wingtip

Here is a link to the script

https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/1/6/16d69c0487eb26ace95ceda1757d4fdfb8358936.py

Thanks for the info. Just as an aside, how do you do your print screens. Mine always come out very low res.

Just tried the script on the JHSYM-10 and it comes in better than most NACA foil DAT’s. Here is a screenshot. Give it a try and play with some point editing to take out the very minor lump I see. You might hurt your head again though doing that stuff!

I have a nice foil function in ORCA3d that I use these days and might try importing your DAT and clean it up there.

Another hint, use the trailing edge thickness as the minimum thickness for the tip. Create a rectangle with a rounded LE (for top or bottom surface only), extrude outwards and blendsrf back to the major tip section. With a bit of playing with this “rectangular” tip section, you can get a very nice tip very easily.

You’re right. And what I’ve seen on “most NACA sections” is the reason I suggested amping up the gain on curvature graph to have a look at this one.

The corner joint on the side is problematic though.

Adrianh,

All the fancy ways to make a wingtip are too much hard work. Let Rhino do the hard work for you instead of trying to force a rail-sweep that will never converge to a proper singularity.

Split your wing surface along the leading and trailing edges so you have two surfaces to work from, then choose the “blend surfaces” command from the “surface” menu ("_BlendSrf"). Pick the “tip” edges of the upper and lower surfaces and adjust the tangency settings, etc., until you have a pleasing shape. If you want a “sheared tip” then just slice the tip at an angle before you start the procedure described above. YMMV, but it works for me.

Caveat: Use airfoils having a blunt trailing edge (finite thickness). You’ll need the thickness for machining tolerances anyway, even if the final product is intended to be a razor’s edge or rounded. The procedure described above may not work for razor or rounded trailing edges; I haven’t tried it. If you must try it and it doesn’t give good results, you’ll find an easy workaround if you think on it for a second or two.

A caution: The airfoil .DAT file you posted was probably privileged data. You really should not post your client’s proprietary information to a public forum.

David
Gall Aerospace

1 Like

It is not a secret design. James puts his airfoils in the public domain.

Thank you, Ukktor; I had not gleaned that from the IP’s context.

The RC glider community has a pretty good open source thing going on airfoils. I found a post from the rcgroups.com forum (where I am also a member) from the designer himself stating that his designs are public. I did not know myself, but assumed the best and was not surprised about the results. RC pilots are good folks!

I must admit that I am still stumped to getting a decent curve for the elevator and the rudder. There is always an odd bulge somewhere.