If they’re so wonderful, you may be wondering, why don’t more people fly the things? Part of the reason is that it’s such a different realm of flight, and so initially demanding on your reflexes. Part of it is the apprehension most people feel from dangling within a spidery framework under a swinging airfoil dependent upon so many interconnected rotating parts. Then again, part of it is the relative scarcity of the things: for every thirty or so airplanes in the US, there’s only one whirlybird. Let’s not forget the cost. In even the most modest trainer, helicopter flight instruction is going to set you back close to three dollars a minute.
STEPPING UP…
Don’t plan on taking notes during your first helicopter lesson, by the way. You won’t have a free hand. Besides, you’ll be too busy remembering to keep your jaw closed. You won’t learn much. Aside from that, even though I just gave you the impression that flying a helicopter isn’t exactly a crowning cerebral achievement, it really is, because there’s a little more to it than meets the eye. Lets start feeling, then…
We’ll use the ubiquitous Robinson R22 as an example. First, your main source of propulsion is that same Skyhawk engine — only now it’s behind you and mounted backwards. It’s de-rated from 160 down to 131 horsepower (for five minutes), and further down to 124 HP, max continuous. So those horses aren’t going to bust a gut, and that’s one reason why engine failures in Robinsons are so very rare. Those two blades — and they’re symmetric, by the way — are underslung on a teetering hinge, they’re about 25 feet across, and they spin counter-clockwise about nine times a second, as viewed from above. (French helicopter blades spin clockwise, wouldn’t’cha know.)
Your CFI runs the preflight, pointing out where the sprag clutch is, explaining that if the engine quits, you won’t drop like a stone but instead will glide — albeit at about a 4:1 slope — as the rotor goes from being a fan to a windmill. He’s shown you all the couplings, bellcranks, jam nuts, safety wires, and telatemps… and, oh yes, the Jesus bolt.
…AND STRAPPING IN
When you’re at the helm, you’re in the right seat in most helicopters (not the left, as in most airplanes). The controls will get your attention next. There are four things that you have to do at the same time… all the time…
- The collective is operated with your left hand, and it articulates much like an emergency parking brake in a car. It controls how much power you use, and you can see its effects on the manifold pressure gauge which, along with all the other dials and gauges, sits in this tiny center console between the two seats. The collective changes the pitch of the main rotor blades, collectively throughout their span — hence the term.
- The throttle — in many piston helicopters, anyway — is the twist-grip, type. It is at the end of the collective and in your hand. Unlike a constant-speed propeller airplane, it controls the rpm, not the manifold pressure. And if you ride a motorcycle, the twist grip, aside from being on your left and not your right, is twisted in the opposite direction from that of your other ‘chopper‘ when you want to add power. (Can you say ‘negative transfer‘?)
- The cyclic is that funny bent pole floating around in front of you. Between that and the rotor blades are linkages, push-pull tubes, bellcranks, and control horns, which are designed to selectively transmit the sideways motion of your right arm into proportional increments in pitch of the rotor ‘disk‘ to achieve greater lift according to where you’ve moved your arm. Further reading: And yes, there’s a compensation for precessive forces, for those of you who might be wondering. (The pitch horns are ‘hooked in‘ 90 degrees out of phase with their point of attachment.)
- That tail rotor is out there to deal with Newton’s law of action and reaction. It’s like a smaller fixed pitch prop, spinning about five times faster than the main rotor. It’s no big deal… it’s just there to blow air off to the left to keep the fuselage from madly rotating in that direction as a result of the main rotor spinning the other way! Being so far aft on the tail boom, there’s quite a leverage arm and it doesn’t take very much force to do the job. It does even less work when you’re moving forward, due to the slipstream effect. In fact, your instructor will let you take the controls in cruise and you’ll be able to fly straight and level… although (at least initially) you may not be able to do both at the same time…
BOTTOM LINE: Learning to fly a helicopter involves patience and dedication. It involves system training, prescient understanding, muscle memory, and a steady hand. And it’s worth it. Next time, we go fly.
