a 5-foot or 6-foot span. The fuselage of an r.c. model should be large enough to carry the radio gear, with removable door panels for easy trouble-shooting. The total weight of the model, including radio equipment, will probably run about 4½ pounds. The com- plete radio equipment weighs about 1 pound. • What stunts and maneuvers are possi-
ble with rudder control? Enough to keep you happy and busy for a few years: turns, spi- rals, figure eights, loops, Immelmanns and spot landings. • How much does a complete radio-con-
trol installation cost? A radio-control unit for operating the rudder, including a trans- mitter, costs about $40 to $60—in addition to the cost of the model. In kit form, one unit sells for about $25. • In addition to the cost of the r.c. unit, is
there any upkeep or maintenance cost? Bat- teries cost about $7.50 for a complete set. You will need a couple of sets a year, de- pending on how much flying you do. Some test equipment will be needed for checking and trouble-shooting. A voltmeter, amme- ter, rheostat, and similar items are fairly necessary items. This auxiliary equipment costs about $10 to $20. Boy, how things have changed! Here’s something else that you might en-
joy reading. Early proportional controls were being built by experimenters. “Simple Proportional Control” was an article in No- vember 1950 Model Airplane News by George Trammell. George writes “Could it be that we have been overlooking some pos-
sibilities in some early proposals for R.C.? In 1935 the writer can remember an article which advocated a form of pulse proportion. That seemed to be the right road to travel, for the ultimate goal of performing aerobat- ics with a radio control model that would match those of the Travelaire or the Waco of that day. Jim Walker has several patents on a form of pulse proportion, but pulse rate is presumably original to this writer. “Actuators are used rather than escape-
ments. There is nothing that ever requires adjustment once an actuator is built. There is nothing about it that is affected by vibra- tion or wind. The actuator is in effect an electric motor which makes only half a turn in either direction. When the voltage is ap- plied, the armature will jump to one of its limits; when the polarity of the voltage is re- versed the armature will jump to its oppo- site limit. The relay in the radio receiver connects the battery voltage to the actuator with one polarity when there is no signal and with the opposite polarity when the sig- nal is received. “Now then, if we use an ordinary push
button to key the transmitter and set the limits on the rudder’s movement so it can- not turn the ship tight enough to spin it, we can fly straight by keying the transmitter on and off evenly. Push the button, and before the plane can start the turn to the right, re- lease the button; again before the ship can turn to the left, press the button. It is evi- dent that some form of mechanical pulser with provisions for varying the on-off pro- portion is necessary.”
Experimenters were busy at work devel-
oping “pulsers” that would vary the signal on/off timing thereby eliminating the need for manual pulsing of the transmitter button. Boy, how things have changed! Plane designs that were being flown in
1950 were primarily rudder only without any throttle control. Bill Winter designed The Citizen expressly for the new Citizen- Ship 465 mc. system that had been recently introduced by Vernon MacNabb Co. Bill’s article explained how he determined the size. Bill made comparisons with Walt Good’s Rudderbug that weighed 74 ounces and had a wing loading of 12.3 ounces per square foot. The Good design was noted for its remarkable glide and several had prob- lems descending when getting in a thermal. Bill decided to increase the wing loading
over the “Bug” by about 2 ounces. This gave a 56-inch span with a 9-inch chord at a design weight of 60 ounces. The Rudder- bug had a power loading of about 247 ounces per cubic inch of displacement. Some models of the day were performing successfully with loadings up to and be- yond 600 ounces. Bill decided on a power loading of 300 ounces per cubic inch and selected the Arden .199. He feared that glow would result in too much power and spark ignition was installed. Can any of you relate to those early days
of R/C when things were not simple but were very challenging? To be able to fly R/C was a special experience and when everything worked properly it was a miracle.
PHOTO: HERB BONE
The 1950 Nats winner (at right) with his Citizen-Ship 465 mc controlled short wave. This photo (above) was provided by Herb Bone, a VR/CS member from Washington state. It shows how we mounted our early receivers by suspending them with rubber bands at all four corners. This was done to isolate the relay from engine vibration. How about those batteries that our planes had to carry around!
FLYING MODELS 45
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