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/96284
term called Cd or drag coefficient. Drag coefficient itself is a sum of two factors: • induced drag, and • the sum of (factor drag + skin friction drag). Induced drag is a function of the lift of the aircraft; factor drag is related to the size and shape of the body; and skin friction drag is a function of how much of the aircraft is in contact with the air. For a more technical description, see these short NASA descriptions: a drag overview and an explanation of induced drag. So will a clipped-wing Maule go faster than a longerwinged version? On the surface (no pun intended) it would seem so; reducing the wing's surface area reduces the skin friction drag. Unfortunately, it's not that simple. Drag is a function of other factors, which may actually get greater as the wing is shortened. For instance, the induced drag coefficient increases when aspect ratio (the span squared over the wing area) goes down. Since the clipped-wing Maule's aspect ratio is lower than the longer-winged version, the induced drag coefficient is higher. The increase in induced drag will work against the decrease in skin friction drag. Depending on whether the aircraft is climbing or cruising, along with other factors that would require equations and calculations, the shorter-winged airplane may or may not go faster in all flight conditions. fabrication and assembly tasks were performed by the amateur(s). The so-called 51-percent rule usually comes into play for designers and builders of kit aircraft since the kit can't be "too complete" for homebuilders. (The EAA has a FAQ about the 51-percent rule.) This project would be a little different—the team would have to show that Chuck had built at least 51 percent of something very close to a production aircraft. Fortunately, the FAA has a 51-percent checklist for just such an occasion. The checklist is helpful for a number of people: kit designers; people who want to build a factory plane; those who wish to use commercial We now return you to nonengineering speak. Chuck's reasons for wanting a clipped-wing Maule were different from David's. Originally Chuck thought of building a clipped-wing Monocoupe because the plane would be easier to build, would respond better in turbulence, land better in crosswinds, be easier to hangar, and therefore, would have less hangar rash. But he wasn't fixated on a Monocoupe; he'd owned three Maules and liked them. David, a former high school science and math teacher, flies his factory-built Maule as a volunteer for LightHawk. His work flying and photographing ecology earned him a national award for volunteering. After Chuck learned of David's background and interest in designing a clipped-winged Maule, Chuck was impressed. He said, "David is where engineering meets art. He can close his eyes and picture the parts of the airplane." Chuck was easily convinced to build a Maule instead of a Monocoupe. Because Maules are factory-built, Chuck and David knew the FAA would have to be convinced that their airplane would be amateur-built. As most EAAers know, for a person to obtain an amateur-build certificate, the builder must show that at least 51 percent of the EAA EXPERIM ENTER 29