Radio Control: Helicopters
THIS month and the next few, the column will be primarily for beginners. Since many of the columns have told about RC helicopter aerobatics, including the "impossible" inverted flight and auto-rotations of our choppers, perhaps I've left out a few notes about the basics. Just how does the darn thing fly? How do I set it up? How do I learn to fly one? How much does it cost? Where do I get one? And the biggie: Why don't you write a book? Those are a few of the questions I heard and, with the exception of the last question, I'll try to answer a few. The answers are not intended to be impressively technical, since at best I am a hobbyist and not an aeronautical engineer.
Radio Control: Helicopters
LAST month we began with a review of the similarities of RC helicopters and RC airplanes. Briefly, the airplane and helicopter, while in forward flight, respond to control inputs to their three basic flight controls in much the same way. And so, once you've mastered hovering your helicopter and progress to forward flight, things get a little easier-but for now, all helicopter flights should begin and end with a transition through hovering flight. So now we leave the airplane in a cloud of dust as it quickly moves down the runway and lifts off in relentless pursuit of forward flight. We, on the other hand, will struggle to learn how to make the helicopter lift off and hover, but please don't hover in that dirty air long.
Radio Control: Helicopters
IN THE last column, we took a look at the collective pitch mechanism for changing the pitch of the tail rotor. We also introduced some similarities of tail rotor collective to the main rotor collective of two-blade "rigid" rotor systems. The flybarless two-blade "rigid" rotor system has been chosen because it is generally less mechanically complicated when compared to rotor systems using a flybar, since control input is introduced directly to the rotor blades rather than through the flybar (sometimes called a servo rotor). In addition, the flybarless system is most like the tail rotor, since the blades are free to pivot about the feathering axis but are otherwise rigidly attached to the rotor hub. But "rigid" rotors are not really rigid, as you will see in the following, as we introduce cyclic pitch changes to the rotor for control purposes.
