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!
Radio Control: Scale
PHOTO Documentation: Knowledgeable contest judges, given a choice between details or shapes shown on a 3-view drawing and also on photos, will usually take the photo as the more reliable information source. Having been fooled by 3-view drawings on numerous occasions in the past, we cannot help but agree with their choice. Unless there are hard dimensions given for a feature, or the model is being designed from dimensioned detail drawings used for the prototype, the modeler is helpless to determine to any degree of exactness the shapes, sizes and positions that will produce a superior plane. Planes that suffer most from inexactness, whether kit or scratch-built, are those that are familiar to everyone. A famous racing plane, for example, that has been photographed profusely during its lifetime will be quite familiar to most modelers and judges. When it is obviously off-scale in some respect, such as having too short a landing gear, wheels too small or too wide apart, or engine compartment undersized, these faults will be painfully apparent to anyone with a good sense of proportions.
Radio Control: Scale
WIRE BRACING: Models of modern aerobatic biplanes, such as Pitts, Smith Miniplane, Christen Eagle, EAA Acro, and Acroduster, will fly without bracing wires. In fact, the addition of wires induces drag that slows the plane and makes it less aerobatic. Wires are merely a cosmetic enhancement to appease our guilty feelings about a plane that looks naked without them. The ample thickness of wings on modern biplanes is sufficient for the deep spars needed to carry the weight and foam wings also have great strength. Models of antique, wire-braced planes will most likely need wires to keep fragile, thin wings from fracturing during abrupt maneuvers. In our experience, the flying wires that carry air loads while the plane is airborne need to be inelastic so that incidence angles will not change with aileron action. Landing wires that support the wings when wheels make contact with the ground need to have some resiliency in order to absorb the shock of an occasional bad landing. This has often resulted in torn wires or, more frequently, a wire anchor ripped from its mounting. We now use springs in the landing wires.
AMA Nats Lincoln '79: RC Scale
WITH places on two RC Scale teams at stake for the Ottawa, Canada Scale World Championships in 1980, the Nats became a highly contested proving ground for team selection. First, second and third place will constitute the Precision Scale and Sport Scale teams. Two tenths of a point, in a total of 733, separated the third- and fourth-place contestants in Precision Scale. Six tenths of a point determined which of the third- and fourth-place modelers became a team member in Sport Scale. The closeness of the finish kept everyone gathered around the score charts until all tabulations had been individually checked for accuracy. The teams will consist of Bob Wischer, George Rose, and Bob Underwood for Precision Scale and George Buso, Ralph Jackson, and Hal Parenti for Sport Scale. While only six Precision Scale planes appeared at the Nats, their quality was so uniformly high that the static scores held no hint of the final outcome, which had to be decided in flying. In Sport Scale, the three winning models had static scores of 100, 100 and 99.3. With 100 representing the score for a perfect airplane it is obvious that the quality was extremely high.
Radio Control: Scale
RC EQUIPMENT for Scale: In the not-to-distant past, scale modelers who wanted interior detailing were faced with the problem of servo location and space. The large servos that were ordinarily mounted near the center of gravity interfered with cabin or cockpit detail because that is also the location for passengers. Four or five cumbersome and heavy servos, to be hidden from view, often meant removing them from center-of-gravity locations to a more convenient point, usually rearward, where they contributed to a tail-heavy condition. In this respect, miniature servos solve a lot of problems, as they can be hidden under seats and beneath the floor.
