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3D printed rib templates

#1
I am getting ready to scratch build a balsa plane and I needed a rib template. Normally, I would draw something up, cad or by hand, and then cut a plywood template to cut ribs. This time I thought I'd try something a little different. I drew up the profile I wanted and made a 3D model. I'll use this printed template, instead of cutting one from ply. So far, it looks like it will work quite well. I will glue sand paper to the back of it, just like the ply, and cut around it with my x-acto. It's a basic Clark-Y. The finished wing will have an 8-1/4" chord. I'll report back on how well it works. So far, the print looks pretty good. Sitting here watching it print, I should have printed a couple of holes to use for clamping the ribs together when I sand them.... I think I will edit the model, and add the holes.

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rockyboy

Skill Collector
Mentor
#4
Very interesting... and with some aluminum tape on the edges I think it would work just fine for hot wire cutting... might need two layers if it starts to mess with the PLA.
 
#5
PLA has a melting point of 150-160 deg. C / 300-320 deg. F.

Polystyrene has a melting point of about 240 deg. C/470 deg. F, and the wire needs to be hotter than that for a proper cut.

If you plan to attach the templates directly to the foam, you should definitely expect it to mess with the PLA.


Another approach that ought to work would be to make "stand-off" templates in stead. You simply design the templates to go 1 or 2 inches or so outside either end of the foam block (i.e. if the section is tapered they will be over-/undersize compared to the section ends) and make them so you can attach them to a bottom carrier plate (extend the ends with feet that set the height or something), that the foam also rests on. And then you can apply power on the inside of the templates, keeping the heat of the wire away from the templates. Makes sense?
 

Turbojoe

Well-known member
#6
Digging up an old thread.....

I was finishing up an old Lee Renaud design Q-Tee laser cut short kit. I got the wing covered real pretty then promptly broke it before ever putting it on the fuselage! Don't ask.......:cry:

I'll only try to salvage the trailing edges. The rest will be trashed then I'll hand cut all new parts. I could have made a plywood or Plexiglas template from the plans but I have a 3D printer so why not print them? I only know Tinkercad and it's almost impossible (for me at least) to create a rib with it. A search for wing ribs on Thingiverse came up with a Clark Y rib file. It's overall design and size was completely different than what I wanted but it at least had the right shape so I downloaded it and got to work. I first resized it to fit the wing chord. Then I had to fill areas to eliminate the double spars top and bottom. Then I added 1/4" spar slots in the original plans location. I'll go conventional and use spruce spars with shear webs. A balsa leading edge is much easier to shape than the original spruce too.

After resizing rib 1 & 2 templates to accommodate the 1/16" sheeting I was ready to print some tests. After making a few spar depth adjustments needed because I changed filament I printed out pairs of all three ribs at 3 MM thickness. They came out perfect! After digging through my scrap balsa box I found enough usable 1/16" balsa to build another plane or two. I made rough cuts of the ribs, clamped them 4 at a time between the templates and went to town with the Perma Grit file and spar slotter then a quick swipe with a block sander. In less than 15 minutes I had 18 beautiful ribs ready to go. It was worth the time spent to make the templates. I really didn't like the original wing design anyway.....

Joe