Hotwire Template Tips

Are you ready to advance beyond folded foamboard wings?

Hotwire cutting is the next step for many builders, and it's not as difficult as it may seem. I find it quicker and easier than folding foamboard. It's also much more accurate, and cheaper if you don't have access to Adams foamboard.

You don't need a fancy power supply, I use a 3S or 4S Lipo depending on how wide my wing is. You don't need fancy wire either, I use stainless steel fishing wire, 40kg breaking strain, and a simple pine wooden frame.

The trickiest part is making the cutting templates. This article explains a quick, cheap and easy method using metal window flashing. It's thin aluminium, readily available from hardware stores, and can be simply cut with scissors.

1. Choose an airfoil

Do an internet search for the airfoil you want and copy the image onto your computer. Good airfoils to look at are:

Clark Y - good all round airfoil for powered planes and slope soarers

RG15 - thin and semi symmetrical for gliders. The Clark Y of the glider world.

Sipkill - has some reflex in the rear section, specially designed for flying wings 

2. Print it at the right scale for your wing.

I use the scale option in my printer window and adjust the value until the print comes out at the right size.

3. Glue the airfoil print to the template material

Spray adhesive works well here

 4. Cut out the airfoil with scissors

Do Not use your partner's prized sewing scissors! Cheaper scissors will do the job just fine.

5. Poke holes for the holding pins

I use 5 large pins to hold the templates in place.

And there you have a cheap, accurate and durable temlpate, which will let you cut beautiful perfect airfoils out of any sort of foam. I use yellow XPS insulation foam. Blue or pink insulation foam is the same stuff.

Here are instructional videos covering template making, hotwire bow and power setup and an arty closeup video of the process.

Here are the maiden flights of two planes built using hotwire cut wings

Good luck and I encourage you to give hotwire cutting a try. It's very rewarding and easier than it looks.

More info here

anewton.net

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