DLG foam or hollow ellipse wings

[cocodet]

I have written a VB software which computes coordinates of ellipsoïdal wings then produces the Gcode (as txt files) of those coordinates needed to cut or mould the wings. One has to add the general instructions to its CNC router (feed, units used that is millimeter....). It does not take the size of the router bit into account. The profiles used are txt files from "profili".

I also have written a similar software to produce "Drela" type wings with a CNC router instead of a hot-wire machine.

Any body interested?

[High Seas]

Do you have a download page you can share the program from or will you post the file here - I'm always interested in an airfoil program. Do you have an english version -- my french is not so good. Thanks and cheers - Jim

[cocodet]

I have attached the program and Drela's profiles for DLG. It has to be run from left to right. Then you will see what it does at each step.

[GoFaster]

I am very interested as I am in the planning stages to build a CNC router to cut foam wing cores. Thank you

- Felix

[cocodet]

Just wrote an english version attached.

[juzwuz]

I'm very interested. I want to model the apogee hand launch glider from http://www.charlesriverrc.org/articles.htm which uses the Drela AG series airfoils. Then use the Vectric software CUT3D to mill out the wing from balsa.

[cocodet]

This software (profdlg) is computing ellipsoïdal wings using Drela's profile or others if so you wish, then produces the Gcode needed to cut them with a CNC router. My experience is that those ellipsoïdal wings give better performance than regular Drela's wing. Supposedly the spitfire had such type of wings and was better than those aircrafts with straight wings. I have attached the soft which computes Drela's type wings, that is a wing originally in two straight sections. Take AG47 for tip and AG 455 for root and run it step by step. You will have a wing close to Drela's. Usually one cuts such wings with a hot wire and templates made using the Profili software. Good luck.

[cocodet]

Hi Juzwuz,

Usually DLG wings are cut in foam or are built as hollow wings with balsa and FG skins. You may wish to look to the way they build the ENCORE for foam core wings at http://www.rcsoaringdigest.com/pdfs/...SD-2006-04.pdf page 32 and following issues then adapt this technology to your needs or have a look at http://www.airplane-model.com/tech-molding.html for the way a hollow wing is built. Profdlga gives core profiles (C... files) and mould profiles (M... files).

Cocodet.

[Glidergider]

Cocodet,
How long does a typical set of wing core take you to cut? Thanks for offering this software. That's really nice of you. I'd love to see some wings you've cut. Do you have to sand the final product much?
Dave

[cocodet]

Hi Glidergider!

I use a 1/4 straight bit and I compute my Gcodes using a 2mm step. I have installed a vacuum table on my hobby CNC router.The first set will take many hours. The values on the left when you start may be changed. They are close to what is used for the Blaster.

First cut the molds of the top parts in foam or presswood (Mhd... and Mhg). Then drill holes in them with grooves on the underside, to allow for the vacuum from the table to go thru the mold. See how they do http://www.rcsoaringdigest.com/pdfs/...SD-2006-04.pdf and following issues. Then cut the top cores (Chd and Chg...) in foam leaving some material below Z0. Then cut with a knife the material around the grooved part and place Chd on Mhd. Then cut the bottom part of your wing with your CNC machine (Cbd and Cbg..). It takes more or less 45 minutes for each operation on the CNC machine. When the moulds are made it means 4 hours per set (3 hours of machining plus 1 hour for adjustments, thinking....) but the result is a much better DLG.
You may use the software to compute Gcodes for your stab and rudder then using "copy, replace..." with "wordpad" and your knowledge of Gcode you can have one only Gcode file for the whole stab or rudder. Since they are smaller it is faster to cut them and it could be a good training, this is my suggestion.
Sanding is limited, less than one hour per set. You still have to make the grooves for the carbon spars...
You may contact me directly if any more questions.
Hope you will enjoy your next home made DLG!

[Glidergider]

Cocodet,
Your link didn't work, but I did some exploring, and found this one.
http://www.rcsoaringdigest.com/pdfs/RCSD-2006/RCSD-2006-09.pdf
Is this the correct link? Page 32?

[cocodet]

For the wings themselves, go to http://www.rcsoaringdigest.com/pdfs/...SD-2006-09.pdf page 32 and follows.