VintageViews T
he Vintage RC Society Yahoo Group,
http://tinyurl.com/kgfgum5, has had some interesting discussion lately about Galloping Ghost. Galloping
Ghost, or GG for short, is a control system that came into being in the late ’50s when es- capement development was mature and many modelers had switched to single chan- nel proportional using a variety of motor driven or magnetic actuators. The escape- ment crowd had learned how to “cascade” es- capements for rudder and elevator control and some compound escapements had an electrical contact which enabled it to actuate a simple escapement for throttle control. Does anyone remember, 1 for right, 2 for left, 3 for up, 4 for down and quick blip or 5 for throttle? What fun!
Well, the proportional crowd wasn’t to be outdone and had to figure out how to get pro- portional elevator with that proportional rudder control from their single-channel pulse transmitter. In the early days of GG no commercial actuators were available and the DIY crowd came up with some very in- teresting home brew actuators. Most were built around the popular and inexpensive Mighty Midget motor. I took some photos of a few of these in my collection and you will see that they relied on a simple rubber band for centering. A screw thread with nut fol- lower was used for throttle control. Here is how it worked. The pulse transmit- ter had to have the ability to vary the pulse width and the pulse rate. Basically these were carrier wave transmitters and the puls- ing simply turned the output signal on and off. When the pulse width was varied the rudder was controlled and when the pulse rate was varied the elevator was controlled. Solid signal on would increase engine speed and solid signal off would decrease engine speed. All this sounds fairly simple except how in the world would the actuator action be translated to the control surfaces? Some actuators were built so a single torque rod was used with a single “crank” at the tail of the plane. This system required rudder and elevator yokes, sometimes called bird cages, attached to the control surfaces. The torque rod would oscillate back and forth with an even pulse rate and fixed pulse width. When either the pulse width or rate (or both) were varied, the control surfaces were biased to one direction or the other. Of course when the control surfaces continued to follow the oscillating torque rod the plane would gallop. Therein lies the term Galloping Ghost. Some modelers figured out how to get control of rudder and elevator using separate torque rods by designing their GG actuator so the crank was at the output of the electric motor rather than at the tail of the plane. As Galloping Ghost became more popular and its advantages over escapements were demonstrated, several manufacturers came to the rescue. Take Off Products by Rand Manufacturing hit the market with a line of actuators that arguably became the most pop- ular GG actuators on the market. No longer
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by bob noll You can reach Bob Nollvia e-mail at
bobrc@aol.com
PHOTOGRAPHY: BOB NOLL
This Galloping Ghost actuator showed up in my collection at some point over the years (above). I don’t know if it was commercially produced. Has anyone seen one like this? It may be homemade. This homemade actuator (below) is a fine example of the many GG actuators that modelers made by themselves around the Mighty Midget motor before commercially made GG actuators where available.
APRIL 2014
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