On my first flight of my XL the right wing came loose at the rear tube and the plane crashed. When I put the right wing on, I must have pushed the tube across into the left wing. The rear tube is much shorter than the front wing tube and so the wing went 90 degrees to the airflow. At first the wing was just loose and I struggled with it for a good 30 seconds, and I almost had it landed in a field. It rolled inverted twice and each time I pushed down elevator to get it higher and upright. I worked it down to 20 feet and I had it upright when the wing went perpendicular to the airflow. The damage was MUCH lighter than it could have been considering the problem. The cowling was cracked in about 20 places and a few holes were made when it hit, but from 20 feet and 20mph level flight into the tight spin with one wing flat against the wind it went down with relatively little engergy compared to a straight in crash. The funky european motor box was shattered. The wing tube was bent 30 degrees back, and the right wingtip was crushed to the second rib from the tip. I estimate it took 15 hours to fix the damage, and $75 in parts (Prop, cowling, covering, wing tube). I couldn't find a 30mm wing tube so I ordered a 1 1/8" wing tube and wrapped the important points with 2" wide teflon tape I had laying around. Three turns made up the 2mm gaps. Does anyone know where I can buy a 30mm tube? Esprit doesn't have them. I did order a new cowling, they're $39.99 but ZB gave it to me for $25. I guess in retrospect a longer rear wing tube or a pin through the middle of that tube would have prevented the problem. And I usually don't misassemble an airplane at the field, but I had a lot of distractions, more than usual that day. I usually only do test flights Saturday morning when it's relatively quiet at the field.
I built a motor mount more suited for the BME 50. Two 3/4" oak beams are braced with 1/4 luan ply braces, and the engine is mounted on aluminum plates that can allow thrust angle adjustments. I kept the two sides of the motor box and integrated them in the new mount. The 3/4" oak pieces weighed the same as the firewall and plastic motor mounts I had bolted the BME 50 to, so I think I broke even on the overall weight. The new cowling will require much less cutting away because the top of the motor mount is much lower than that motor box, so I can fit the cowling over the exhaust stacks. The new wing tube is .049 thick instead of.035 tubing so I gained two ounces there. I would still like a 30mm tube. I have to pin the rear tube in place also. I tried to CA it in place but it did not stick to the aluminum. I'm kinda glad, I really like everything to be removable anyway. The fuse and tail and left wing suffered no damage at all. I plan on flying the plane again this weekend if possible. I CA'd the cowling back together and put some of those bullet-hole stickers over the cracks so it looks like it is shot up but with the new cowl it will look good as new. -Tom