Slow combat plane: "Slow Bat"

Theo, my son and I have been building with foam for quite some time. Learned all kinds of tricks. The main thing to flying a foamie is light and power. What are you powering it with? Cleaning up your trailing edge would certainly assist in good flying. I usually clean them up prior to installation by trimming them up with a straight edge and a new razor blade. Yours could be sanded. The spars can be shaved down flush using a razor plane followed by a block sander.One thing very important to these planes is the trailing edge. Generally prior to gluing the wood tips on, I glue a piece of weed whacker cord (heavy fishing line) centered on the trailing edge from tip to tip. The cord is one piece and I drill a small hole through the fuse for it to pass through and the tips get applied over the ends. Don't get too aggressive with the foam as it can really put a divot in it. One thing that can really help is if you have some lightweight silkspan or OO silkspan. Apply a wet strip onto the trailing edge using thinned white glue lapping 1" top and bottom from root to tip. This will improve the strength immensely. Where is the bellcrank being installed? I suppose on top of the fuse in the hardwood area? Whenever a bellcrank is on top and is slightly higher than the tip guide exiting at the wingtip the vertical CG is off which usually makes the outboard wing fly tip high. Don't add more tip weight to compensate for this. Using your iron on a low setting twist the outboard wing near the trailing edge up and iron and hold until it cools. Circle the iron when heating and do not stay in one spot. A key to knowing how hot is the extruded beads of foam will begin to raise up. Your at the max heat so anymore will melt it. Good luck and happy flying. Ken