Free Flight: Duration
A FEW COLUMNS BACK, I asked if anyone out there had any real-world experiences with turbulators. Jim O'Reilly sent along a letter tracing his experiences: "You asked for additional poop on turbulators. I have a story that speaks to the turbulator spar issue. In a 1986 Vol Libre, Hans Gremmer published a piece on wind-tunnel tests of actual model construction airfoils. Included were the Hofsas Espada (clean and with a couple of turbulator styles) and my favorite, the Benedek B7406f with no on-purpose turbulation other than the leading-edge discontinuity. The two clear winners were the Espada with a 2D turbulator and the B7406f.
Free Flight Duration
SOME YEARS BACK, I was involved in a rather unusual flyoff. We were flying at the old Huntsville, Alabama, airport. Closed to full-sized aircraft, it was used for model flying and just about everything else. By the time you factored in the golf course, the garbage dump, and the other encroachments, there wasn't a lot of room. In other words, it was a typical free flight site. Two of us had made the three two-minute maxes in Unlimited Rubber. With the existing drift, upping the max to three minutes, or even two-and-a-half, would have meant some lost models. So the contest director suggested that we both launch at the same time, and whoever was highest at two minutes would be the winner. There was enough drift so it was easy to tell who was highest. (It wasn't me.)
Free Flight: Duration
ANOTHER MODEL OF the Year: Among the models chosen by the National Free Flight Society for recognition in the 1995 Sympo is the Wakefield design of Ukrainian flier Eugene Gorban. With this state-of-the-art model Gorban has won the European championships and placed well up at several World Championships. He recently won the 14-round Max Men Annual at Lost Hills with a max in the nine-minute flyoff round. Although Gorban's model looks rather simple and straightforward, it is really quite an elegant piece of craftsmanship. The double-tapered wing uses a carbon-fiber spar and a D-box shell of Kevlar and thin aluminum.
Free Flight Duration
FOR THE LAST FEW months we've been looking at a few of the Ten Models of the Year for 1995, selected by the National Free Flight Society. The model shown this month is Randy Weiler's #16 F1A. Randy has participated in the team selection program seven times and made the team on five occasions. He most recently represented the United States at the World Championships held this past July in Hungary. Like most modern F1As, #16 makes extensive use of composite construction. And like most Nordics, it looks deceptively simple. What you can't see in the three-views are the multifunction clockwork timer and the special towhook that allows both circle towing to find the best air and a bunt launch to gain an additional 10 meters of height.
Free Flight: Duration
HOW LONG? Aspect ratio (A/R)-the relationship of a wing's span to its average chord-is one of the many factors you must consider when designing a new model. A look at sailplanes, either RC models or fullscale, might convince you that a long, narrow wing is the best way to maximize glide performance. But is a high-aspect-ratio wing always the best choice? And how high is high? For some events, such as P-30 and Pee Wee-30, the rules limit the wingspan. In these cases, you should use as low an aspect ratio as possible, to maximize wing area.
