Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/378679
14 Vol.3 No.9 / September 2014 RISING TO THE CHALLENGE Cub builders, we found that this particular kit had a reputa- tion for not being as precise as it should be. To most guys, that made little dif erence because they could rig-out any fl ying dif culties. But I just couldn't handle that. For decades I had been obsessed with the precision that's involved in build- ing championship race cars, where precision is everything. So I wouldn't be able to sleep at night knowing some critical dimensions were of . "We went after the airplane with a tape measure and level and found that what we had been hearing was right. Some of the dimensions were of far enough that we were going to have to do some surgery and welding. The rear of the longe- rons, for instance, were close to an inch out of place, so the horizontal stabilizer was, too. It would have made the airplane almost impossible to land with any load in the airplane be- cause I couldn't get enough up elevator. So we cut the longe- rons loose and squared everything away. Then we checked the main spar fi ttings and found they put the wings on the fuselage at a dif erent angle of indices. They were nearly 3 degrees dif erent. Yeah, you can asymmetrically droop fl aps or ailerons to make it fl y straight, but that just wasn't right; so more surgery was in order." Every time Mark turned around he found things that wouldn't work for him or which the original Super Cub also didn't have exactly right. He said, "On a Super Cub, the engine sits slightly out of line with the airframe centerline, which causes undue drag. So we got ahold of Mark Englerth of ThrustLine Products of Alaska who makes a modifi cation for the mount that lines everything up. But we're so used to seeing Super Cubs with droopy noses that mine looks as if the nose bowl is a little high. "That change was just one of many that became like drop- ping a rock in the pond…the ripples…demand that other things be changed. And this was to be a continuing theme for the entire project. It would be four steps ahead and three back be- cause of the secondary and tertiary changes that would follow behind seemingly minor modifi cations. Photography by Jim Koepnick The side, aft cargo door is a common modifi cation to Cubs and involves moving some of the internal structure, but the increased utility makes it worth the effort. Mark Hein.