Control Line: Aerobatics
IN FINE-TUNING our beautiful creations I have discussed many features: engines, props, balance, etc. But one of the major factors I haven't featured is the direct connection to the airplane and pilot: the flying lines. This time I'm going to limit the discussion to the trimming aspect, not the selection of the actual material (solids, cable, diameters, etc.). What we're going to explore is the relationships in what the lines do.
Control Line: Aerobatics
ALL RIGHT, so it happened! You've had an accident, and you broke your pride-and-joy model. Now what? As an Air Force flier, the emergency procedures sections that I committed to memory always started with "Stop, think, and collect your wits," and that's good advice for our situation. Whatever the cause, it's always easy to get frustrated and angry and trash the remains. Resist that temptation, because there are many options that may not be readily apparent to you at the moment of disaster. The first order of business is to make sure that you don't do any further damage. Before you move the remains, look at them and determine the best way to retrieve the parts. If there is fuel left in the tank and there's an active leak or the potential for raw fuel to contaminate the remains, fix this situation immediately. Fuel on the model's pieces will seriously affect any subsequent repair efforts. This is also a good time to carefully clean up the oil residue.
Control Line: Aerobatics
WHEN YOU ARRIVE at the Nationals, you never know what "character" the week will take on. Sometimes it's a dominant flier, the weather, the site, or all three. This time we had absolutely wonderful, mild weather. It was a marvelous setting, and I would have to say that this was really a "social" Nationals. Perhaps it's because I remember the old days, but to see and chat with many of the top competitors from the '50s and '60s was a trip down memory lane. Perhaps it was the central location; maybe it was just time to be part of this event again! Stories of the old days abounded from Jim Silhavy, Les McDonald, Rolland McDonald, Bob Gialdini, George Aldrich, Dave Hemstraught, Stan Powell, John Davis, Keith Trostle, Charlie Reeves, Gary Phelps, and of course, Bob Gieseke and Bill Werwage. It was a different era, long gone, but friendships forged in competition really have stood the test of time.
Control Line: Aerobatics
THERE ARE MANY times that I wish I could deliver a new airplane to someone who is really good at sorting out problems, and pick it up later-all trimmed out. But for most of us that simply is not possible, so we have to struggle and endure. This means that it behooves us to understand the trimming process. There have been some excellent articles in Flying Models, PAMPA, and Model Aviation, and I urge you to seek them out and read them thoroughly (PAMPA Products, Box 2026, Loomis CA 95650-2026; Tel.: [916] 721-4328. Call Mary Gebhart or Bob Hazle). The very narrow area in trimming I want to discuss is tip-weight adjustment. Until the advent of tip-weight boxes in the early 1970s, most plans called for approximately 3/4 ounce (or more precisely, one rolled up, empty Ambroid tube). As the adjustable feature became more popular, many experts said to load the tip until the wing hinges or throws in certain spots-like the top of the hourglass, or outside squares.
Control Line: Aerobatics
Over the years (many years, in my case), you pick up bits of technology that work and some that don't work. Many times, an approach that seems on the surface to be an exciting way to solve a problem just doesn't prove to be an acceptable longterm solution. Part of the equation is that we in Precision Aerobatics deal with constant vibration, longterm exposure to heat and ultraviolet rays, and prolonged high flight loads. Faced with this environment, we need to look at longterm solutions to engineering problems; solutions that last at least years and a thousand flights. My philosophy is simple: Use what works over time and evolve it so that it suits your needs. I have my approach to engineering a front end; Randy Smith has his; and Windy Urtnowski uses the Big Jim Pattern Master style. They work, but they also evolve over time. Sometimes people tend to reinvent problems because the approach is attractive and it's easy to assume the past away. There are two areas where solutions have been recently proposed that are known to fail, and that's what I'd like to address.
