# Hot wire foam wing cores one man cutting

Hi all, sorry if this is a little off topic, but sometimes I need to cut foam cores to build planes.

So finally I decided to put together a little tool to calculate the position of the fixed position of the hot wire, in the case of one man work.

This way it is possible to cut foam cores alone, using only one airfoil template.

Here is a screenshot :

It should be correct, but if someone find something wrong, please tell me and I will fix it.

I thought this could be useful to some one, so here is it.

Documenti.zip

Best regards

Views: 4037

Comment by SaadT on March 7, 2012 at 11:12pm

Thanks for sharing Riccardo. I've also found Google sketchup to be very useful for such things. Before, i used to draw and design my airplanes on paper, but now i just sketch them on google sketchup and it makes it much easier. Since it's sort-of a CAD software, you can do measurements on the sketch which helps when building the actual thing.

Comment by eduardo on March 8, 2012 at 1:45pm

i dont understand how you cut the wing with fixed point wire.

Have a video ?

Comment by Don Brooks on March 8, 2012 at 2:01pm
Comment by Riccardo Kuebler on March 8, 2012 at 2:07pm

Eduardo,

sorry, no (not yet).

You fix the wire at one point, e.g. inserting it in a v shape aluminium plate or everything else.

Then you compute where to place the foam panel to be cut, with the tool (it works only with trapezoidal wings, but for rectangular wings there are other techniques for one man band work).

You fix then the airfoil template to the widest part of the foam panel (the main triangle base) and you guide the hot wire from one part to the other.

Hopefully this is more clear :)

Best regards,

Ric

Comment by Riccardo Kuebler on March 8, 2012 at 2:24pm

Don,

thanks for the video link, but I think this one is better.

He is controlling better speed and wire temperature. In the other video, wire temperature seems to me way to high, it is cutting 4 times the wire diameter. Which airfoil does he get ? For a simple plane this will work, but if you are searching for good airfoil performances, the cutting has to be more accurate.

Speed seems to me too high to. The wire will cut in a non straight line, so another limit to good airfoil.

Please watch at the glance of the foam core after the cut of the video I propose.

Sorry to be finicky, but this has to be a precision work. This is the reason I did this tool, otherwise you could find the fixed point by trials.

Best regards,

Ric

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