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/254584
24 Vol.3 No.2 / Februar y 2014 RETURN OF A HOMEBUILT LEGEND If one were to put the '63 Butler Midget Mustang next to other, more modern MM-1s, it would be difficult to notice any differences. However, since Butler didn't have plans and was a devoted and imaginative craftsman, internally there are lots of subtle differences. With no fully devel- oped plans to follow (the designer, Dave Long, died before he produced them), Butler just used his common sense and abilities to fill in the gaps. So the fuel system, control systems, and other internal parts differ from what are now accepted MM-1 designs. There is no fi berglass on the airplane. The wingtips, for instance, are aluminum, hammered in two pieces, the now invisible gas weld where they join runs down the centerline. Although it's not known exactly what alloy Butler used, when free-forming the cowl, in all probability it was the fa- vorite of most aluminum craftsmen—3003. With no in-process photos to tell us Butler's secrets and not being able to peek inside the cowl, one could conclude that the inlet areas were probably formed separately from the cheeks themselves, then welded together. The cheeks were formed in manageable sections, hammered into shot bags, and fi nished on a Butler– designed and built English wheel to match a skeletal wooden form. Then all the sections were gas welded together. As shown in the polished surfaces on his second, retractable gear, MM-1, he used no fi ller to hide imperfections. Inasmuch as it is known that there is little or no fi ller on the airplane, one has to marvel at the way in which Butler was able to skin the wings and fuselage with no deformation whatsoever at the rivets. Also, while at Oshkosh 2013, the weather condi- tions changed from sunny and warm to cloudy and cool, yet the skins never appeared to change. They were always drum-tight without a hint of waves. The engine, an O-200, was built by Mattituck, which installed an Airfl ow Performance fuel-injection system and a four-into-one exhaust, both helping to boost the engine an un- known amount. According to Lew's pilot, Chris Gardener, who brought the airplane into Oshkosh, the engine/prop combina- tion must be right because it is very smooth. At 6 feet 2 inches tall with a 36-inch inseam, Chris looked out of place standing next to the airplane at Oshkosh. It was easy to picture him folded up like a pocketknife in the airplane, but he said it wasn't uncomfortable at all, and he made the Dal- las to OSH fl ight in one day. "Two-hour legs are comfortable, both fuelwise and physi- cally," he said. "The controls on the airplane are quite quick on all axis, but it is actually fairly stable and presented no problem on my cross-countries." Chris had fl own aircraft such as Pitts and Extras prior to the MM-1, so he was prepared. But, as hundreds of other Midget Mustang pilots have reported, it wasn't at all dif cult to fl y. "On my fi rst fl ight, I didn't know what to expect," Chris said, "but it was really quite civilized and performs really well. The composite MT electric prop uses a rheostat to set the rpm, and it really holds the rpm and is fairly quick to auto- adjust unless you're making hard pitch changes. Then it gets just a little behind. "It stalls at 80 mph indicated clean and around 65 to 69 with full fl aps, 25 degrees, down. It cruises at about 160 mph indicated, and I fl y downwind at 120 and fi nal at 100 mph. We're over the fence at 85 to 90 mph, and it generally pays of at 78 to 80 in fl air. Three-point landings work well and it tracks really straight. The tail wheel is directly linked to the rudder so it reacts quickly; but you don't really need to do much with the rudder on rollout. I should mention that we have Grove gear legs on it that are gun drilled, airfoiled, and polished. They are running on Grove wheels and brakes, and the geometry must be almost perfect because of the way it handles on the runway." One of the big disappointments for the Butler Mustang crew at Oshkosh was that it didn't get both of Butler's Mustangs to the event. Nancy Pierce was fl ying her Butler retract MM-1 and had left with Chris, both planning on displaying the two airplanes together. Unfortunately, her airplane developed a mechanical problem and had to abort. Maybe next year the two will make it and we'll be able to enjoy the artifacts left behind by Jim Lloyd Butler, a man who lived to create aerial art. Budd Davisson is an aeronautical engineer, has fl own more than 300 different aircraft types, and published four books and more than 4,000 ar- ticles. He is editor-in-chief of Flight Journal magazine and a fl ight instructor primarily in Pitts/tailwheel aircraft. Visit him at www.Airbum.com. T e airplane had no corrosion because, Lew said, "T e build work by Butler was so thorough as to keep the airplane going for 100 years. Photography by Phil High The MT composite, electrically controllable propeller greatly improved the airplane's performance both on takeoff and cruise where it indicates 160 mph at 5.7 gph. E A A E X P _ F e b 1 4 . i n d d 2 4 EAAEXP_Feb14.indd 24 2 / 3 / 1 4 3 : 1 6 P M 2/3/14 3:16 PM