Radio Control: Scale
EAA Model Show: After observing many years of mall shows, we have found the perfect environment for a model aircraft show. On March 20, 1988 we attended the first annual EAA Air Adventure Museum Model Aircraft Show at Wittman Field in Oshkosh, WI. The event was co-sponsored by EAA and two local clubs: Winnebago RC Fliers and Valley Aero Modelers. Show managers for EAA were Education Director Chuck Larsen and Museum Director Carl Swickley. The vast museum building, due for further enlargement before the next show, has no space shortage. Polished floors and sparkling airplane displays accented the models, surrounded by aircraft of wide variety from the Wright Flier replica to a duplicate Voyager fuselage. The emphasis was on history and home-built types.
Radio Control: Scale
MODEL STRUCTURES: Balsa has been the basic structural material for our model aircraft since our beginnings in the hobby dating back to the late Twenties. In the early years, our only real concern was the relative hardness of the 1/16-in.-sq. sticks that were used for spars and longerons of rubber-powered Scale models. Fundamentals change with time, and we now weigh each sheet of balsa to determine its ultimate use. None of those early models contained a scrap of plywood. The only hardwood was the occasional bit of bamboo in wing tips and tail surface outlines. With the advent of RC came the use of heavier materials.
Radio Control: Scale
SCALE INSTRUMENT panels can be produced photographically. The technique is quite simple for anyone having a camera that will focus close to the subject, or equipped with an inexpensive close-up lens attachment. Full-size instruments must be available, either in the plane being modeled or a similar plane. In order to be certain that the image size on the negative will be correct and would not need to be reduced or enlarged later, a focus distance must be found. This is done by placing a small piece of tracing paper in the camera with the back open or removed, so that the paper is in the exact position normally occupied by film.
Radio Control: Scale
INSTABILITY Revisited: The model is a splendid example of scale beauty, the culmination of a year's earnest effort, and this is the moment the builder has awaited. The excitement builds as engine is started, needle valve is set to the optimum, and it is checked again to be certain all controls are functional. The plane is taxied to take-off position, the throttle opened, it accelerates down the runway, lifts off too early, flips on its back, and with a sickening sound returns to earth with parts scattering. Why? What happened? Was it pilot error or a hidden flaw in construction? Radio problems? Probably none of these was the real culprit here. Too often we hear of models that are difficult to handle whether they are kit or scratch built. The complaint most heard involves a tendency to snap-roll, usually during takeoff, landing, or turning maneuvers-and the kit designer or producer gets the blame. Numerous faults in construction or balance can result in the destructive snap-roll. Warped wings caused by working on a warped work bench or by too tight covering material can result in a condition known as wash-in, where the angle of incidence increases toward the wing tip. This error results in the tips stalling before the wing root. The cure is a flat working surface or the use of low shrink covering materials and dope.
Radio Control: Scale
CONTROL Reversal: The subject of instability was explored in a recent column. We touched on the treacherous situation in which the control stick needed to be pushed, rather than pulled, to regain flying speed and stop the model's descent. Having to do this is a manifestation of the phenomenon called control reversal. Scale models are particularly susceptible because they often have low power relative to their weight. With throttle open and flying at full speed, if we apply up elevator, the nose will rise and the plane will climb. If this process is repeated several times with additional up elevator, we soon reach the point where the nose comes up but there is no climb because there is insufficient power available to maintain speed. If up elevator control is moved further, the nose will again rise but the plane will begin to descend in a mushing condition. At this point we see the effect of control reversal. Up elevator has caused the airplane to descend!
