It has taken a while to get

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15 BASICS HOVERING Hovering It has taken a while to get here, but this is what all the building and planning were for to see light under those skids. But this is also the time when you have to be particularly careful and patient. Resist the urge to get started to fly before you re really ready. It s natural to want to fly, but it s easy to go too far too quickly and damage the machine you have cherished for so long. With this in mind, your number-one goal is not really to learn how to hover but to keep the helicopter in good mechanical condition so that you will have something to practice with. I have seen many people try to learn too quickly and crash. They could have avoided this if they had tried to learn at a more reasonable pace. Remember: if your helicopter is down for repairs, you can t learn to fly it, so your numberone goal is to avoid damaging your helicopter. Learning how to hover is your second goal. With all the building and setup behind you, this is a time when you expect to progress very quickly, and unless you have trained on a flight simulator, it can be mildly discouraging to find that helicopters are not as simple as they may seem. But there isn t anything like flying a helicopter. No matter what your life experience even if you ve flown a full-size helicopter -trying to master an RC helicopter takes skills and coordination that you have never had to draw on before. Don t expect success to come 100 overnight; in fact, I would be surprised if you had any real control over the helicopter going through your first few tanks of fuel. Sometimes, your helicopter seems to have a mind of its own, especially if it s out of balance and trim. But with patience and proper training, you ll soon learn to hover and fly. One of the best habits to get into is to perform a thorough preflight check at least, before the first flight of the day. In the last chapter, you have already learned how to make dynamic adjustments, and a full preflight may not be needed right now, but certainly, look the helicopter over and check for anything that may have vibrated loose. Every brand Figure 15-1. This is the standard hover position: 30 degrees off the tail, about 15 feet away and facing parallel with the helicopter. Note that the transmitter antenna points in the same direction as the helicopter. The transmitter tray enhances a relaxed flying style. Practice looking at both sides of the helicopter. and model of helicopter has certain areas that have to be watched, and the idea is to find these areas on your machine before you do any damage. In Chapter 1, I discussed my techniques for holding the transmitter sticks. If you have not read Chapter 1 recently, I suggest that you reread it now, as you are ready to begin your hovering practice. First, fill the fuel tank and check the transmitter to make sure that all of the switches and trims are in their proper positions. Then start the engine and carry the helicopter to the training area; put it on the ground facing into the wind. Stand behind the helicopter

THE BASICS OF RC HELIS 15 and about 30 degrees to the side, as shown in Figure 15.1. This is what I call the standard hovering position, and it s where you should return after each attempt at hovering. Initially, it doesn t matter whether you stand to the right or the left of the helicopter because I will ask you to move from one side to the other to make sure that you don t favor one particular side. What does matter right now is that you have a good enough view of the helicopter to see small changes in attitude and make any corrections required, and you re in a position to get out of its way if you lose control. Do not stand any closer to the helicopter, and don t have people near you when you practice. They ll distract you or get in your way if you need to move fast. THE GROUND HOVER You will practice on a hard surface such as concrete or a softer surface such as grass. Each requires a particular technique as you begin to hover, so I ll discuss them separately. Hard takeoff surface. With the helicopter facing into the wind, move to the standard hovering position already described. As you add power and collective, one of the helicopter s first reactions will be to yaw (turn its nose to the right or left). This is because the main rotor blades produce torque, and the helicopter reacts to that before the tail rotor has got up to speed to counteract it. Remember that when you adjusted the tail rotor, it was for hover rpm. Yawing is normal, but be prepared for it so that you don t think anything is wrong and start to change the trim settings. Instead, use the left stick to keep the nose straight as you add power; you can even add and reduce power slightly to give you a chance to practice with Figure 15-2. During liftoff, the rotor system s lift will follow the slope of the ground and cause the helicopter to drift in that direction. Figure 15-3. Use cyclic inputs to keep the rotor disc level during liftoff to eliminate drift. the left stick (rudder). Always remember to look at and fly the nose and not the tail. If you practice in a light, steady breeze (and without the use of a heading-hold gyro), the large vertical fin will also help to keep the nose pointing into the wind, so there will be less need for control on your part. As you continue to add power and collective, the helicopter will get light on its skids, and because the ground probably isn t completely level, there s a breeze, the helicopter is slightly out of trim, etc., you will notice the helicopter starting to drift slightly. Counter this drift with the cyclic controls. But because the rotor speed is rather low and there is still weight on the skids, it will take a lot of correction to stop the drift or to get the heli to move in another direction. If you ve set everything correctly, the helicopter will barely get airborne with full power and collective. If it lifts off, just decrease the collective trim slightly so that it will only slide 101

15 HOVERING around on the pavement and won t leave the ground. The only thing that will hurt your new helicopter is hitting the ground, so let s keep it on the ground and just slide it around while you get a feel for the controls. At first, the helicopter will move on its own, and you won t really be able to counter its movements. Don t be discouraged; it s normal and is part of learning. But after a few seconds not minutes of trying to gain control, bring the throttle back to idle and think about what happened and which control response you made. Were you watching the nose? Is the nose still pointing into the wind? Are you moving the control stick in the direction in which you want the helicopter to move? Are you coordinating aileron and elevator for proper control? Remember that if the surface is not level, the helicopter will want to go downhill, and you will have to counter this (Figure 15-2). For now, just try to get a feel for the controls. Later perhaps several tanks of fuel later try to keep the helicopter in one area and make it move in the direction you command. As you gain confidence and when you have some control over the helicopter, it will be time to get it slightly airborne, but more on that in a minute. Grass takeoff. Much of the information given in the section on a hard surface applies to flying off grass as well. The helicopter will not, however, be as free to drift because of the drag of the grass. This means that you will have to get the helicopter a little lighter on the skids before there will be any movement. But initially, I still recommend that you adjust the collective trim to keep the helicopter on the ground at full throttle. I recommend this 102 because you can do some very good early training by watching the training gear and the main rotor disc. As you add power and collective, look to see whether the rotor disc is horizontal. How about the training-gear legs? Are they all bearing the same weight, or are one or two bending because the helicopter is tilting to their side? Move the aileron and elevator control sticks slightly and see how it affects the rotor disc and the load put on every leg of the training gear. Your goal now is to get a feel for the controls, learn to increase power and collective and keep the helicopter s weight the same on all the training-gear legs. Also notice that because the grass holds the helicopter in position, you barely have to control the tail rotor. Again, move the nose around as the rotor speed increases, and if it is light enough, it will move. And when you can make corrections automatically without thinking, it s time to think about getting the helicopter just slightly airborne. But don t be in a hurry to progress to hovering. Figure 15-4. The dark tape on this Sceadu 30 s white rotor blades helps to define the rotor disc. Figure 15-5. Hovering the Sceadu 30 with training gear at the Manatee RC field in Florida. Note the small fenced areas to protect pilots while others are flying; the large fence protects the flightline. You ll find it a lot easier to hover when you have a good basic understanding of the helicopter and its controls, and you ve practiced looking at the helicopter and transferring what you see into the proper control movements at the transmitter. It may take several practice sessions for you to feel comfortable with this, so progress at your own pace. A lot will depend on how much time you can devote to training and how often you can practice during the week. FIRST HOVER ATTEMPTS Now that you have a feel for the controls and the helicopter s response to control inputs, you are ready to get the helicopter off the ground. When some people think of hovering, they have visions of taking the helicopter smoothly up to 4 or 5 feet right away; this is a sure way of having to learn how to make repairs early. Your first attempts to hover will be at only several inches off the ground and for only a few seconds. Increase the hovering time

THE BASICS OF RC HELIS 15 as you gain confidence, but still keep the helicopter low to avoid doing any damage. Remember, if you can hover at 1 inch you can hover at 1 foot, or at 10 feet, or at 100 feet. The helicopter handles the same at almost all altitudes. Put the helicopter in front of you, go to your regular hover position, and slightly increase the collective-pitch trim. Then smoothly add power and collective and get to the now-familiar position of having the helicopter light on the skids. Then increase the collective ever so slightly, and the helicopter will lift off straight up, if you re lucky, but that isn t very likely. As the helicopter leaves the ground, it may tilt for the reasons already mentioned, and it s your job to counter that and to keep the helicopter in the correct hover position. Try for a couple of seconds, and then bring the helicopter back to the ground and analyze your progress. Did the helicopter try to go one way or the other? If it did, how did you correct it? Did you make the proper correction or not? What will you do better the next time? Do the trims need adjusting? If they do, move the appropriate trim slightly in the direction that s opposite to where the helicopter wants to go, and try the control response again. Now it s time to try it again, but again, just lift slightly off the ground for a short time. As you continue to progress, you will gradually be able to keep the helicopter off the ground for longer periods of time, but you will still feel that you have little, if any, real control over its movements. This is completely normal, so don t be discouraged. It will come, and then you ll be surprised by how easy it is. Do s & don ts Between tanks of fuel, rest for a few minutes and go over some of these basic points. DO S Relax. If you concentrate too hard, you may have a death grip on the transmitter, and then it will be almost impossible to get a feel for the sticks and make the proper response. And don t twist or lean in the direction in which you want the helicopter to move. Stay loose. Even if you think you are relaxed, have a friend watch you while you practice to assess whether you really are relaxed. It s hard to relax at first, and your friend may let you know where you re tensing up. Stand erect with your arms hanging comfortably and the transmitter held easily, but firmly, in your hands. Keep your head and body straight; your leaning could be transferred into unwanted control movements. DON TS Don t quickly add or cut power. This could cause the helicopter to get too high and then come down too hard and get damaged. Don t ever try to back up or let the tail drop lower than its normal hover position. This is the major cause of tail-boom strikes because the helicopter will almost surely descend as the tail is allowed to drop, and the helicopter will hit the ground tail first. The tail rotor will be damaged, and the main blades will strike the tail boom. This is why I had you tilt the swashplate slightly forward during initial setup to build in a little nosedown trim. If the helicopter moves forward on its own, certainly add up-elevator to try to stop it, but quickly correct back to the level position when the movement is stopped. Don t ever practice when you aren t in your usual position in relation to the helicopter. You should always be in the proper position to reinforce the feeling of control you have, even if at first you don t feel you have much control at all. If the helicopter turns right or left or lands farther away from you, turn it into the wind and walk to your proper hover position before you try anything else. Be sure to practice hovering from both sides of the helicopter, or you will get a liking for one side or the other, and this is a bad habit that you ll have to break later. Don t ever look at or fly the tail. Remember that the tail-rotor control is to correct the nose position. But the spinning tail rotor is all too easy to watch; don t let yourself get into this bad habit. Always focus on the back of an imaginary pilot s head, and be aware of the position of the rotor disc. Wherever the rotor disc tilts, the helicopter is sure to follow. ADVANCED HOVERING At this stage of learning, advanced hovering means flying the helicopter out of its hover position and bringing it back again. Don t attempt this until you are fairly proficient at hovering in a somewhat fixed position. I don t mean that you have to be able to keep the helicopter in a dead-still hover, but you should be able to keep it within a 3-foot circle (about 1 meter). When you can comfortably do this, you can increase the helicopter s altitude to about 3 feet or so, and, again, get comfortable with the helicopter at this height while you 103

15 HOVERING 104 Figure 15-6. This is trouble waiting to happen. Although the RotoPod training gear will protect the helicopter, allowing the tail to hit the ground will result in a boom strike. maintain control within the area mentioned. Also, before you move the helicopter away from its usual hover position, be sure that you understand its basic movements and know which control responses to make to alter or correct them. To illustrate: let s suppose the helicopter is in a stationary hover and a gust of wind causes the nose to drop slightly. This, in turn, causes the helicopter to move forward slightly, and your initial reaction is to raise its nose back to the level hover attitude. But this level hover attitude will not stop the helicopter s forward movement, and you have to make a further aft cyclic command to raise the nose slightly higher and stop the forward movement. And when the helicopter is again stationary, you must drop the nose slightly back to its normal hover position. This means that you made three distinct control responses to make one very minor correction to the pitch axis, and certainly, other corrections to the other flight axes will also be required, at the same time. As you can imagine, it can be very difficult to figure out which correction is needed and how much correction to make. But let s go back to the helicopter in a stationary hover for another demonstration. Again, a gust of wind causes the nose to drop, but you realize this before the helicopter has a chance to move, and you immediately make an aft cyclic correction to raise the nose back to its hover position. In this example, the helicopter didn t move, and it required only one correction to regain its normal hover position. And this anticipation is exactly what you should strive for as you practice: make the proper correction before the helicopter has a chance to move. This takes a lot of practice, but it s important to understand the principle behind hovering and to get a feel for the helicopter s overall attitude so that you ll eventually be able to make a correction the instant it s required. Once you feel comfortable in a hover, fly the helicopter about 2 meters farther away and to the side, and hover at that position. When you feel that you have complete control in that unfamiliar position, bring the helicopter back to its normal hover position. Then do the same thing on the other side, still keeping the helicopter about 2 meters away from you. As you gain experience, you ll be able to move the helicopter increasingly farther away in this side movement until you feel comfortable when it s about 5 meters or so away from you. Then, instead of hovering at that point, return it to the normal hover position; and then do the same on the other side. This practice will help you learn how to keep the helicopter under control as it moves and changes directions but is based on a familiar position. When you can make the helicopter move to the right and left away from you and bring it back, it s time to start incorporating the tail rotor into your practice. As the helicopter starts to move to the right from its normal hover position, add a little right tail rotor to let the nose swing slightly and I mean slightly to the right. Then, as the helicopter reaches the position farthest away from you, bring it back, but add a little left tail rotor to again swing the nose around in the direction in which it is flying. As you progress in this way, you will soon be able to move the helicopter to the right and left as you coordinate with the tail rotor to fly a figure-8 in front of yourself. When you can fly this figure-8 comfortably, you have mastered one of the hardest parts of helicopter flying. There s certainly a lot more to learn, but this is the foundation for everything else, and you ll now have more fun as you gain control of the helicopter and learn its many maneuvers.