Radio Control: Scale
LIQUID COOLING: Engine cooling in Scale models can be a serious problem, particularly for the modeler who values his engines and searches for ways to extend their lives. The tightly-cowled engine is vulnerable to excessive wear due to overheating damage. Adding extra lubricant to fuel can help avoid the wear, but this introduces another variable, with the possibility that it may be forgotten when the model isn't flown often. A letter from a reader requested information about liquid cooling for tightly-cowled engines. Almost any prototype that has a liquid-cooled engine, for example WW II fighters or those aircraft with pusher propellers, presents a problem to the Scale modeler when there are no suitably large openings for ventilation.
Radio Control: Scale
INSTALLING EQUIPMENT: Scale models with ornate cabin or cockpit interiors were once a rare sight. Today, modelers consider some amount of interior detail to be nothing unusual, although the really complete cockpit is not seen too often. The degree of completeness depends upon the modeler's desire to reproduce all aspects of the prototype and is somewhat dependent upon having access to a full-size aircraft to copy. Photos alone are a help, but there is no substitute for having direct measurements from an original. Adding seats, upholstery, and controls-for even the most spartan of interiors-can introduce a tight squeeze on space for servos, receiver, and batteries which always seem to occupy the space normally used by passengers in civil-type aircraft.
Radio Control: Scale
DESIGN YOUR OWN. Building Scale models from kits or plans can be very satisfying, but there are modelers who prefer something more rewarding: an airplane that hasn't been done in quantity or in the size desired. These persons follow another path to satisfaction in designing, building, and learning to fly an outstanding aircraft that attracts attention. Original-design models also have better-than-average contest-winning potential. For example, more than half of the top-placing Nats RC Scale entries were originals. Any number of Scale enthusiasts have thought seriously about building a rare bird but aren't quite certain of methods and procedures. The project is forever postponed for lack of information, and incentive is lacking because there are an overwhelming number of kits and plans waiting to be built. Some of us have gathered photos, books, magazines and three-view drawings for most of our lives. There will probably never be enough time to build models from all of these sources.
Radio Control: Scale
FACT OR FICTION? One of the fictional theories about model flying is the importance of scale effect, our bugaboo of the past that supposedly kept a model from flying in a manner somewhat similar to its prototype. We have been asked whether scale effect makes changes necessary in airfoils or tail surface areas. Our answer is that present-day RC Scale models don't need these changes. There is no doubt that scale effect is a factor on very small, light, and slow-flying models such as Peanut Scale, rubber-powered, or Schoolyard Scale RC types. However, in the size models we are now flying, with .40, .60, or 1.20 engines, the effect isn't evident. This is really accentuated in our experience when we compare flight of our models with that of the exact full-size counterparts and find remarkable similarities. Giant Scale models are even more like their prototypes.
Radio Control: Scale
LONGITUDINAL STABILITY. In response to our March column on the subject of unexpected stalls, we received a letter from James M. Ruley, who is an aerospace engineer specializing in aircraft stability and control and working for Aeronautical Systems Division, USAF, Wright-Patterson AFB. His discussion on stability theory follows: "Longitudinal stability is the tendency of an aircraft which has been trimmed to fly at a certain angle of attack (AOA) to return to that AOA when disturbed from it. It is necessary for an airplane to have longitudinal stability in order for it to be controllable. Therefore, it is important to ensure that our model airplanes are longitudinally stable.
