Radio Control: Scale
NEW RC FREQUENCIES. At a recent local RC meeting, our District VII Frequency Coordinator, Pete Waters, was present with his charts of our area, showing the location of industrial transmitters that posed a threat to flying RC models. It was disclosed that a local telephone company had built a transmitter on one of the commonly-used RC frequencies, 75.64 MHz, a few miles distant from our club flying field. Without Pete's help, we would have gone on using 75.64 until someone was shot down. Even the loss of a trainer built in a few weeks is lamentable, but the model could also have been a Scale type, with 2,000 hours of building time.
Radio Control: Scale
FOAM-CUTTER CONTROL. Our June 1983 column contained a photo showing a control box for hot-wire foam cutting. Letters were received inquiring about the contents of the box, and whether it was a purchased item or homemade. The control was asembled here in our workshop, using standard components purchased from local suppliers. The aluminum enclosure is a standard electrical components box 4 in. × 5 in. × 6 in. from a radio parts supply store. Inside are two transformers. The first is a Powerstat variable autotransformer which is the product of Superior Electric Co. of Bristol, CT. It is a type 10B with a 120-volt input and a variable 0-to-120-volt output. It isn't safe to use its output directly on the hot wire because of the shock hazard. (Its output is not isolated from the house power lines.) Touching any metal parts of the foam cutter could be hazardous when standing on a concrete floor or touching a grounded object. Any current flow of 5 mA or greater, through the human body, contracts muscles, and the person is unable to release his grip. This may be lethal, if the heart is affected.
Radio Control: Scale
SOLDERING AND BRAZING. Soft soldering, with lead-tin alloys, is the most common method of joining steel or brass parts. Low joint-strength is the main disadvantage when using ordinary solder. Advantages are ease of fabrication, low tool cost, and relative ease of repairs. Joints can be re-melted and disassembled for repair. A 100-watt soldering iron (which isn't really iron, but copper), or a 150-watt solder gun will serve most modeling purposes.
Radio Control: Scale
IMPROVING OLD MODELS. Our ancient Douglas Mailplane, before its retirement into the new AMA museum, was flying better than at any time during its 13-year life. The important difference in flight handling came about when the old four-wire servos were replaced with new three-wire Royal Titans. We never regarded the older servos as being less reliable in operation, but proof of improvement is in the comparison between flights before and after the change. Most pronounced improvement was the new-found ability to fly with hands off the transmitter controls for extended periods. This is the result of more positive servo-centering and greater torque output. Most noticeable change was the improvement in aileron response. Four very large ailerons could now be moved and centered with the 38 in.-oz. torque for a more positive return to neutral.
Radio Control: Scale
RENO NATS: High altitude and hot weather in August will have an influence on our flights at Reno. Stead Field, site of the Nats outdoor activity, is at an altitude of about one mile above sea level and this height, combined with expected temperatures of 80º or more, will place the density altitude in the range between 8,000 and 9,000 feet. Combined high temperature and altitude will affect models here as though the field height is over 1 1/2 miles! Modelers who regularly fly at Reno, as well as those in Colorado and New Mexico, tell us that the altitude has little effect. Having witnessed a few problems at the Reno Scale World Championships in 1982, we are aware that there is an effect.
