When most people consider bush flying, their first thoughts are likely of Super Cubs, 185s Beavers and other fixed wing aircraft. Thoughts of flying seaplanes or in the mountains often comes second but most, don’t think about helicopters at all. That’s a pity, as there are a good number of helicopters in bush country. Given the vertical take-off and landing (VTOL) ability of helicopters, they are a natural in bush country. Let’s consider, very rudimentarily, what it is like to fly a helicopter. This is far from an exhaustive guide to the subject, but hopefully, we can demystify some aspects of helicopter flight. We’ll also consider flying a typical, big main rotor and small tail rotor helicopter and leave the Russian coaxial Kamovs (or other, non-traditional helicopter layout) for someone else to learn how to fly. Oh, if you read this article, buy a helicopter on eBay and have at it just on the basis of what you’ve read here, you’re not going to be with the rest of us much longer—this is merely for information and in no way substitutes for proper helicopter flight training.
To many fixed wing pilots, the mere thought of flying a helicopter is incomprehensible. The helicopter’s controls work much differently than an airplane and the pilot uses all of his or her hands and feet to fly them at all times. Frequency changes on radios are done quickly and whatever hand is used to change the radio frequency quickly goes back to whatever it was controlling before. Unlike airplanes, helicopters have no real stability in flight and they most be constantly flown. No helicopter (and no airplane, for that matter) is truly a “hands-off” machine, but they are not difficult to fly either. They’re just different.
Before we get into the nuts and bolts of helicopter flying, let’s in a very roundabout way, answer the perennial fixed wing pilot’s helicopter question. What is helicopter flying like as compared to an airplane? Much of helicopter flying is just the same as flying anything else (planes, dirigibles, autogyros whatever) weather has to be considered and appreciated for what it is, engines have to be properly operated, and fuel and oil must be monitored. Knowing the abilities of the machine and pilot are essential to all forms of flying, so much of the basic airmanship or airwomanship, is the same for a helicopter as it for any other flying machine. In these respects, airplane pilots already know quite a bit about helicopter flying before they ever lay hands on a helicopter. Much of helicopter flying is vastly different, so many plane pilots ask what the controls are like. We’ll get into a little more detail later, but generally helicopter controls are a little more sensitive than similar controls in airplanes. As to exactly how it feels to fly a helicopter, well, it feels a little different to every pilot, and there’s no good way to describe it in words. The best analogy is that it’s like riding a bike, a little tentative at first, but easily mastered and really no harder than bike riding.
Now some might think the analogy to riding bikes is way too simple and woefully inadequate. If one falls off a bike, the risk is a scraped palms and/or knees, if one splats a helicopter, a scraped knee—if the only injury—is a miracle. No so fast, let’s remember our bygone youthful experiences. We need to go back in time when we determinedly, but shakily, stood astride our bikes ready to conquer the world. Despite the assurances of our peers, we all secretly harbored in our mind that the bicycle silly-assed contraption invented by a deranged lunatic. Strange, now as adults, many of us have the same conception of helicopter. But anyway, back to our bikes. We fell down, we wove, we tried stopping them with our feet and somehow—just somehow—we managed to learn to ride them. Now think about it for a moment. You learned to use your ENTIRE body to ride a bike (even though most of us weren’t aware of it at the time) and we also used all or our hands and feet to control the contraption too. Sure we learned to be cool and ride with no hands later, but at first it was all hands, feet and concentration for us. We found out that the bike was easier to ride with some speed and that it controlled differently with speed. At slow speed we turned it with the handlebars to turn, at higher speeds we leaned to turn and did not move the handlebars much at all. In short, when we learned to ride a bike, we were doing something much more complicated than flying a helicopter. We only have to use our hands and feet to fly a helicopter, not our entire body.
At this point many fixed wing pilots will chime up and say, “okay, but bikes don’t have engine gauges and flight instruments and fuel tanks to watch over, so your bicycle analogy is still stupid.” Yes, it is true, bikes don’t have all those things but you know what does? Airplanes. And we aren’t afraid of all those things when we get into an airplane, so in that respect, it’s just the basic airmanship we discussed earlier. Yes, there are some different things to watch on a helicopter than an airplane, but that’s it. No one will receive the Nobel Peace Prize for learning how to fly a helicopter, because it’s just not that difficult, or noteworthy, of an accomplishment. Believe it or not, even mediocre pilots can master the helicopter.
At this juncture, let’s consider something that further proves our bike riding point. Occasionally a fixed-wing pilot will try to flummox us with this zinger: “Hey, I got an hour in a Robinson R-22 and there was no way I could even remotely hover it, the instructor was on the controls all the time. I call bullshit on your ‘helicopters are easy’ statement. Helicopters are hard!” Once again, did you learn to ride a bike in an hour? Think back, we may have learned to awkwardly control a bike in an hour, but we really didn’t know what it was all about until we had ridden it for weeks. Most pilots can learn to solo a helicopter in 15-20 hours, which is not much different than it took us to solo an airplane. When we first learned to fly an airplane, most of us had a feeling that we could fly a plane once it was in the air, but not so with the helicopter. The instructor definitely had to step in from time to time. Yes, helicopter flying is not as simple as straight and level airplane flying, seaplane licenses or tail wheel endorsements are, but once again, helicopters are not hard, just different.
Let's take a break from our helicopter training and watch a video about a deer that is rescued by a helicopter. While the video is pretty cool, please note that we are in no way responsible for the title, "Helicopter Gives Deer Blow Job". Despite the cheap humor, its an interesting video.
Helicopter Flying 101
Now, if you’re still reading this, you probably are ready for Helicopters 101, the controls of a helicopter. To do this, let’s sit in an imaginary helicopter, I’ll guide you through the controls. Directly in front of us, between our legs is a stick, just like a Piper Cub. If it’s a Robinson (the kind most people learn to fly today) the stick is centrally mounted with a spindle arm—it functions just the same as the more traditional sticks. This is called the CYCLIC and it controls the disk angle of the main rotor. UNLIKE and airplane, we push it forward to go forward and pull it back to slow down or move backward. If we move it to the side, the helicopter turns to that side. At our feet, looking just like rudder pedals in an airplane, are anti-torque pedals. These pedals control the tail rotor and help us keep the tail where it needs to be. They are somewhat like rudder pedals except, we usually do not need them to make coordinated turns in a helicopter like we do in a plane. What we do use them for is power changes or main rotor blade pitch changes. Remember a helicopter has a large main rotor which is like a large gyroscope on top of the helicopter. If we speed it up or slow it down or change its pitch, we, according to Newton’s Third Law, have to counter-act an equal and opposite reaction. The reaction kicks the tail one way or another and we correct this reaction with the anti-torque pedals.
Isaac Newton knew a few things about flying helicopters.
Next we have a throttle but it’s a little different than on an airplane. As we sit in the helicopter and let our left arm fall to our side, our arm will likely come to rest on a funny little bar that’s like the parking brake lever on some cars. Bonus points if you have guessed this isn’t really a parking brake for our helicopter. This is the COLLECTIVE and it moves up and down. At its tip, it has a twisty handle just like a motorcycle grip and the twisty grip is the throttle, just like a motorcycle. If we pull the bar up or down it changes the blade angle of the main rotor. It is what we use to make the helicopter go up and down, in conjunction with the throttle. Once again, this part is like flying an airplane, we add power and adjust attitude to climb, reverse the process and we descend. On the helicopter we pull up and add power (the Robinson helicopters have a governor that automatically adds or subtracts power for us) to go up, and we reverse the process to go down. Now many piston helicopters do not have a governor like the Robinson, but due to CORRELATION (the finer points of which are beyond the scope or this article) the engine generally keeps power where it needs to be without a governor and without our intervention—we just have to monitor it to make sure everything is where it needs to be. At worst, we have to adjust the throttle one way or another, but just accept on faith at this juncture, that’s it’s not a big hairy deal.
Helicopter Flying 201
You’ve now mastered the basic flight controls of a helicopter so, let’s take it up in the air and see what it is like. In our magical helicopter we don’t have to preflight it or make sure its got oil, or even worry if Donny Dumbass is by the tail waiting to get his head chopped off as we start ‘er up. Start up and all that tends to be a little model specific and really beyond the scope of a basic article. We’ve got everything turning as it should be, our gas and oil is fine and we’re ready to fly.
Like an airplane we need to take-off. Take offs are a lot different in a helicopter than they are in a plane, but don’t worry, they’re actually kinda fun. To take off we are SLOWLY going to pull up on the collective and “feel” the helicopter as it starts getting lighter and lighter. We are going to feel if it’s trying to move in any direction, even before we lift off and we will sense this through the cyclic stick, anti-torque pedals and slight lurches that the helicopter may make. We adjust the cyclic and anti-torque pedals accordingly. You see, helicopters will have a tendency to want to move about on the ground just before they become airborne and we won’t want them to move until they are airborne. In most helicopters some forward movement when the skids are still in contact with the ground is acceptable, but sideways or backward movement is a definite NO-NO. Why? Here’s a high falooting term that Isaac Newton didn’t know, but don’t worry, it’s not hard to understand. DYNAMIC ROLLOVER. If the skid of a helicopter is in contact with the ground while the helicopter is moving, the skid can easily get hung up on any ridge, pavement crack or other ground irregularity. If the skid sticks on this ridge, the bottom of the helicopter will stop moving and the top will pivot around the stuck skid. If the helicopter pivots too much, there is not sufficient control authority to stop the rolling motion caused by the pivot and the helicopter will literally pivot itself onto its side, regardless of how much cyclic input we have to counter the rolling motion. That’s right, we can have the cyclic full to the left and still have the helicopter pull itself over onto its right side if we allow the pivot angle to become too great. When this happens, the main rotor shatters, our flight is over, and we look very foolish as we crawl out of our helicopter as it lies on its side. Dynamic rollovers are rarely fatal incidents to the helicopter occupants, but they typically will total the helicopter. Dynamic rollovers are not only a concern on take-off, they can occur during landing, while landing on slopes or if we snag a power cable while flying with one of our skids.
Once again, we prevent dynamic rollover by “feeling” the helicopter as it lifts off and also, by slowly lifting the collective. Let’s address what we do in both instances. With the cyclic in our hand as we lift off we can “feel” a point where the cyclic has little or no force on it and we have to apply force (albeit ever so slight) to make it move off this spot. Where is this spot? It moves around depending upon wind, helicopter load, and conditions. How do we find the “spot”? As we slowly raise the collective we can move the cyclic in very small increments to find where its neutral point is. We may also need to use the anti-torque pedals too to prevent movement, but most of it is cyclic. We also raise the collective very slowly so it gives us a chance to “feel” the very subtle feel of the helicopter. In movies and on television, helicopters often zip right off the ground, but beginners don’t take helicopters off in this manner. We are very careful, slow and deliberate on takeoff lest we end up on our side. Moving backward has less risk of a roll over but it can damage the tail rotor and we can inadvertently “buzz-saw” something we don’t want to with our tail rotor if we move backwards.
As the helicopter breaks ground, generally we’ll have to press the left anti-torque pedal a little and move the cyclic a little forward much like we have to feed in a little right rudder as we break ground in an airplane. Once in the air, usually we’ll stabilize the helicopter in a hover. Typically we will need to begin our climb into the wind—if possible—and if we are at an airport, we’ll want to hover taxi over to the active runway and climb out as if we were an airplane. That way, other pilots will be looking for us were they would be looking for other airplanes, so it lessens the chance of collision. Hovering is a little like the bike riding experience, we could describe it, but we wouldn’t gain any appreciable knowledge from it, so it’s a “do it to understand it” type of thing. It’s not difficult but it does take some practice, particularly in the Robinson helicopters which are a bit more twitchy that others.
During climb-out our concern will be airspeed and altitude, just like in an airplane. We will carefully monitor both as we climb. What makes a helicopter different from a plane is in the event of an engine failure. Like a plane, we’re going to come down, and like a plane we can still live through it. Unlike a plane, if we are too slow but have plenty of altitude, things can go badly for us, similarly if we are too low and too fast, things will go badly. Though somewhat beyond the scope of this article, too high and too slow is risky as too low and too fast is—both conditions severely impair our ability to auto rotate (more on this later) and are unsafe. So during climb we keep climbing as we should and we keep our airspeed where it should be too. We don’t run the risk of stalling like an airplane, but there are other nasty things that can happen to us if our airspeed isn’t right. If we’re really inept, instead of stalling we could get into a VORTEX RING STATE, or settling with power, but more on this later.
Once we are done climbing, we can level out and fly straight an level. In this state the helicopter flies the most like an airplane, but remember, it is still different. If we want to go up and down, we do it with the collective and throttle. If we want to go faster we push the cyclic more forward (of course there are limits, and we can’t keeping pushing the collective forward until we reach mach airspeeds). We turn the helicopter with the cyclic and, as mentioned earlier, we typically don’t need the anti-torque pedals much, if at all, to make a coordinated turn.
So far, so good, but since this is all imaginary helicopter flying, let’s do some crazy stuff we really wouldn’t do in real life—come on, it’ll be fun. Let’s say I am sitting right next to you in the helicopter, I get a wild look in my eyes as I look at you. I turn the mags off, throw the key out of the helicopter and emit a maniacal laugh as I do it. Like it or lump it, we’re about to learn all about the dreaded auto rotations as we begin plummeting out of the sky. We are either going to learn how to auto rotate very soon or were going to learn what it is like to be pancakes. Typically the helicopter will have a clutch that allows the main rotor to pinwheel freely in the event of an engine failure, if it doesn’t, or the clutch doesn’t disconnect the engine drive train, we’re going to have to do that very quickly as we start going down (and believe me, we better start going down quickly or we will loose main rotor RPM and then, well, then you’re going on a hell ride with a laughing maniac at your side). We pretty much want to immediately push the collective down to keep our main rotor speed up. When we do this, believe me you, we are going to come down, roller-coaster fast (not so fast in turbine powered helicopters, but fast nonetheless). That’s okay, that’s what we want to do. We will start looking for a place to sit the helicopter down but our main concern here will be to keep coming down and to keep that main rotor spinning at a good clip. Just before we splat into the ground we’re going to yank the collective up as if our lives depended upon it, because in fact, our lives do depend on it. We’ll use that rotor speed to create some very short lived lift and stop our rapid descent. The trick to this is not pulling the collective too soon. It will provide lift, but only for a short time, so we don’t want to do it when we’re still hundreds of feet above the ground. If we do it right, we’ll most likely walk away without a scratch on either ourselves or the helicopter and then—and only then—you can slap the laughing maniac as hard as you like. Go ahead, you’ll feel better.
Now sometimes airplane pilots will get a bit hypocritical here without thinking the whole thing through. They’ll say, “my God, that sounds dangerous, I wouldn’t want to ever fly a contraption like that.” Really? What happens in a Super Cub when the engine quits? What happens if we fly it too slow as we descend? Pretty much the same thing as happens in a helicopter, except in a Cub, I, the laughing maniac, would be either in front or behind you, and not at your side. Otherwise, things are pretty much the same.
Speaking of laughing maniacs, we know there are some thrill seekers out there who will enjoy the helicopter stunts from the movie Deadly Encounter, so we have included a video clip for you.
We’re not done with the lunacy yet, so don’t get all smug about your wonderful auto rotation with the maniac just yet. Because we have a magical helicopter, we’re back up in the air ready to try our luck again. I’ll just suspicion—because I’m good at these things—that we’re going to be a bit hapless. Anyhow, here we go. We flying along way up in the air and I decide wouldn’t it be nice if we stopped. Helicopters can hover, so what’s wrong with stopping in mid-air after all? So we stop and we stay stopped. Let’s say I then get the absolutely brilliant idea to descend vertically. After all, helicopters are VTOL, aren’t they? It’s about here that the maniacal laughing starts again. We run a good risk of descending into our own downwash which will disrupt the airflow over our main rotor. When this happens, our helicopter goes down once again, and it can even do so with full power. It’s a bit like a stall in an airplane and we can do that in an airplane, full power or no power. This is vortex ring state or settling with power, because helicopters will still fall in this state, even with full power. What do we do to get out of this mess? We start going forward to get out of the down wash. Until we get out of the down wash, the cyclic will feel as if it is connected to no more than a blob of jelly, like the controls of some planes when they are stalled. Other ways we can get into the mess of vortex ring state is to fly into the downwash of another helicopter, wingtip vortex of an airplane, or the most likely candidate, flying too slow while descending to land. We will definitely want to maintain some forward speed as we come down for landing and avoid getting into our own downwash. Once again, not much different than a Super Cub, we don’t want to fly it too slow on approach either.
After all we’ve been through the actual landing of a helicopter tends to be a bit anticlimactic. We generally descend into a hover, watching our airspeed and making corrections, hover over our touch down spot and gently ease it onto the ground by slowly lowering the collective. It’s a little more involved than just this, but that’s the general picture.
Now there are several things we haven’t discussed such as translation, recirculation, retreating blade stall, transitional lift and more. But this should give you a good idea what helicopter flying is about without having to read a hundred pages of material. Helicopter flying is no more difficult than flying airplanes and any decent airplane pilot can learn to fly a helicopter. It’s not cheap, but it isn’t the horrendously difficult task like many airplane pilots assume.
ADD TO YOUR SOCIAL BOOKMARKS:BlinkDel.icio.usDigg FurlGoogleSimpySpurlTechnoratiY! MyWeb