using craft materials and tools to make airplane part templates

No update for a couple of weeks, but that doesn't mean I've been idle on the project.  Picked up six sheets of 020 aluminum last week.  They are 12 feet long and fit (barely) in the back of the family truck.  The shipping materials actually weigh much more than the aluminum itself.  Lots of straps to hold it in and a cheap fabric red flag on the end to keep it (closer to) legal.

I griped a bit about this on Facebook (who doesn't).  It's very hard to understand why raw aluminum made here in Ontario is shipped out of country to be processed into sheets, then sold back at a premium here in Ontario.  I'm all for North American jobs, but this is a good example how much manufacturing base our country has given away since I was born.

Off to the shop last Saturday.  Nothing better than a hot tea in my Canuckmug.

The wing skeleton takes up much if not all the workbench and the other workbench is being used for Ron as he works on the Aeronca Scout finishing touches before it gets painted.  A roll of plush carpet on the floor makes a good cutting mat:

First wing skin cut to size and rolled out on the skeleton.  This one is the upper outboard skin:

Lined up, the pilot A3 holes at the spar clecoed in place.  With those secure, the skin naturally curves down across the wing ribs.  It actually starts looking like an aerofoil!  Sweet!

Marked up the rib lines and the cross L lines that define the rivet lines for both.  The cross L's help stiffen the skin over the wing bays.  The whole skin will come off again once I finish the pilot holes at the spar, to drill pilot holes for the ribs and L's.

Spent the rest of the day making the L's and helping Ron install the new windshield in the Scout.  Learned a bunch about drilling windshields so they don't crack - this will be handy when I install mine.

I also started working on the fuel tanks.  I've got the first tank skin cut to size which is just a large folded rectangle (think four sided rectangular box).  I'll need to make the tank sides and the wooden form to bend the edge flanges for welding it all up.

I managed to secure a copy of the drawings for the extended fuel tank.  I put these into LibreCAD.  This is the template for the wooden form directly from the dimensions in the plans.  The tank will fit in the first wing bay between the first and second wing ribs, main spar and rear channel:

​The template for the aluminum sides was derived form this using the drawing tools available in LibreCAD - I learned a few new tricks how to make parallel lines, offset by 6 mm which leaves room for the flanges. It's very close in shape to the wing ribs, just a bit smaller.   I also created crosshairs on the drawing  where the relief holes at the corners are drilled and also where the fuel outlet of the tank is, including allowances for the fold of the flanges:

You may recall from a previous post, my wife Brenda bought a CriCut Maker craft printer/plotter/cutter.  I have a fair amount of time to think while driving to/from work sites and it donned on me to ask if the CriCut could accept native .DXF files that LibreCad produces and if it does, could it cut these templates from Bristol board?

Turns out, it CAN!  I wish I knew this a long time ago, it would have saved me a ton of time cutting templates from converted PDF files, but the CriCut is fairly recent in the crafters market.  Oh well, still have lots of templates still to make!

The CriCut can cut and print up to (almost) 12 inches wide by 24 inches tall with a little margin included in that.  My wing skin templates had to be sliced down a bit in order to fit, but I was able to get the most important shapes (the complex curves) plotted and cut.

It starts with a standard piece Bristol board, cut down to 12 x 24 inches:

The CriCut uses an adhesive cutting mat - something similar to 3M Post-It notes on a larger scale.  I laid the mat on top of the marked Bristol board to make sure it fit correctly.  (The whimsical black cartoon cat and logo on the inside of the machine lid is something Brenda added herself, using vinyl and made on the CriCut):

With the Bristol board cut to size, it gets stuck down on the mat to wait loading into the printer:

The Design Space software for the CriCut takes a bit of getting used to, but isn't too difficult to figure out.  As I stated above, to make the upper wing skin tip template fit, I had to slice it in half in LibreCad and import both halves into Design Space.  

Follow the directions on Design Space to choose and load your material, and press go.  The CriCut cutter automatically checks depth of the cutter and goes about making the cuts defined by the DXF file:

Almost impossible to see in the picture below but the cutter follows the lines of the uploaded DXF file.  Once the cutting is complete, unload the mat:

Bristol board isn't one of the default materials in Design Space, so I just chose the heaviest card stock listed and asked the machine to cut with more pressure.  Almost completely through and enough to easily remove the cut outs:

Emboldened by my success, I make the template for the outboard wing nose skin.  It too turned out perfectly:

Here is what I got done over the course of about 45 minutes.  Like I said, the machine and software make it easy to create perfect templates.  On the bottom are the two template pieces that make the tank sides.  You can even have the CriCut print and cut on the same piece just by choosing what you want done with each line segment.  You can see the crosshairs I spoke of above, drawn right on the template.

Back in the shop for the day tomorrow.  Goal is to get the pilot holes drilled in this upper outboard skin, make the upper inboard skin and drill it (it covers the fuel tank) and maybe get the blanks made for the tank sides.

I'll need to obtain the hardware for the tanks soon.  These include the fuel outlet fittings, the quick drains and the fuel filler necks.  Lots to think about :)

​Thanks for reading, stay tuned for more.