by Chuck Spencer

This past winter I visited several Swap shops and sold some stuff I've had laying around for years that I wi11 never use. Among the stuff were two sets of foam wing cores. I had a few interested parties say that they didn't like foam cores because they weren't strong enough. Years ago I devised a method of inserting a fiber glass arrow shaft as a spar to keep the wing panel from flexing. It's simple to do and takes about a half hour to get set up and do two panels. First put the foam core back in it's saddle, both top and bottom, and tape it so it can't shift.

Put it on your bench and weigh it down with books, tools or whatever so it can't move, then take a piece of scrap pine or whatever hard wood you have laying around and block it up so it's half the thickness of the airfoil at it's thickest part. Glue or nai1 a couple of pieces to this to form a track the width of a piece of 3/16 or 1/4 inch wire. This is used as a guide and should be about a foot long and should be square with the end of the root of the core. It makes no difference whether the core itself as tapered or not. It's in it's saddle and the hole will come out straight.

Now grind a long tapered point on the piece of wire. Use a piece three feet long. I use a new piece of music wire, Take your propane torch and heat the point till it's red hot. Lay the wire in the guide and suddenly push it quickly, clear through the wing core. This takes about 10 seconds. If you don't get to the other end the first time, heat and do it again. If your core is longer than 3 feet, back the wire up with another piece held in alignment with a piece of brass tubing. Pull the wire out and insert an arrow shaft. It will be a tight fit and will require no adhesive to hold it in place.

For a quarter inch arrow shaft, use 3/16" wire. For a 5/16" shaft use quarter inch wire. For longer shafts, go to a store where large kites are sold and buy a 1onger shaft. They come in various lengths and diameters. I once let a friend fly an airplane with this set up. He lost control and put the wing edgewise into a fence while going straight down. This wing was also covered with 1/64" ply veneer. There was a notch in the leading edge back to the arrow shaft spar, and that was it. The wing lived!