Helicopters: A Primer

Taken from The Sky Behind Me, a Memoir of Flying and Life , Chapter 6: First Takeoff: The Mattel Messerschmitt
“This is as good a time as any for a short primer on how helicopters fly, the aerodynamics of rotary-wing flight. The main blades provide the lift, of course. But they also provide the steering mechanism for all intended directions. In the cockpit, the main stick the pilot holds in his or her right hand is called the cyclic. The cyclic is for horizontal flight. Ease the cyclic to the right, the aircraft goes right. Ease it left, and left you go. Forward, backward, sideways, all maneuvers in the horizontal plane come from moving the cyclic.
To the pilot’s left, on the floor of the aircraft, is another stick called the collective pitch, or collective for short. It’s for vertical flight. Pull the collective up, you go up. Push it down, down you go. The important thing about the collective is that, as it changes, the pitch in all main blades changes ‘collectively’ and equally. Moving the collective up and down also changes the amount of torque produced by the blades spinning around upstairs.
This is where the two pedals on the floor come in. Those two controls put pitch in and out of the tail rotor, which acts against all the torque mentioned above. The technical name for the tail rotor is the anti-torque rotor. The easiest way to explain what it does is to remove it from the aircraft, and show what would happen. Without the tail rotor, when we pull the collective up, the aircraft would come up, as it’s supposed to. But the entire airframe would also spin around in the opposite direction of the main rotor. The upshot of this is, that when changing collective settings, up or down, the correct amount of pedal must be used to add or remove pitch in the tail rotor as well. It’s simple; it’s complicated.” People asked me often through the years to explain what makes a helicopter fly, what keeps it aloft, the basics of so called rotary-wing aviation. I decided to blog about it in case some of those folks, or you perhaps, still wonder. The above description is, of course, simplistic; there are many factors involved in taking a helicopter into the air and safely landing one again. These are the basics, and, I hope, reasonably easy to imagine. What I allude to in the book, over and over, is that which may be the primary consideration in flying a helicopter, and that is balance. It’s simple physics, really. If something is out of balance it must be corrected, or the aircraft won’t continue flying. Lift must balance with drag; yaw must balance with trim; fuel must balance with time; speed must balance with power etc. etc. What a veteran pilot knows, and what’s so hard to convey to non-flyers is that it really is a metaphor for a life well lived. And, as in life, when everything is in balance, the sense of contentment is sublime. Tune in tomorrow for a description of what is perhaps a helicopter’s most exotic, and yet most useful feature, its ability to land with no power at all–at all! Talk about sublime!