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The Stall Turn

This maneuver is like the Immelmann Turn in that it is performed upward away from the ground, making it a safe maneuver to practice, providing you don't get a flameout and have to land dead stick. If you have an advanced trainer or beginning Pattern plane as discussed in Lesson 1 that will stall vertically without the main wing rolling on application of rudder, this maneuver could moved from Lesson 5 all the way up to Lesson 2. This is because of its relative simplicity and safety. Performed upwind, the stall turn consists of pulling from level flight up into a vertical climb. The throttle is gradually reduced to idle or high idle, and the plane is allowed to coast to a vertical stall. At the moment of complete stall, full rudder is applied, causing the plan to turn 180 degrees through its yaw axis, as in a wingover. The plane descends back through the same path it traveled upward, throttle being applied back to full as the plane pulls out to level flight downwind. Your rudder usually has to be capable of at least 30 degrees of arc in order to have enough throw to create a stall turn. If you apply rudder before a complete stall occurs, or with two much engine power, the plane will do a "power wingover", rather than a true stall turn. In a good stall turn, the plane will tightly turn and fall back through a path within only two wing spans of the climbing path. In a power wingover, the width between the ascending and descending paths will be greater than that. While the engine should be at idle or at most high idle as the model stalls and turns over on its main wing, on occasion you have to supply a short blast of engine power to aid the turn. This blast may be necessary because you waited too long into the stall to apply rudder, or other factors such as wind interfering with a good stall turn. This maneuver is easy to perform with a cross or quartering windd, because if you stall turn toward the wind, you have the wind pressure on the tail helping you swing the plane over. (In the double stall turn and the Figure M, where two stall turns have to be performed, in opposite directions, such a cross wind becomes a major handicap on the stall done away from the wind rather than into it. Not only must the pilot swing the tail into the wind to turn, the whole air mass is moving the plane out of its flight corridor as it hands there, struggling to turn. But breathe easy--we won't attempt such advanced maneuvers in these lessons.) As a sport flier, it pays for you to use such a cross wind to make an easy stall turn. But there is one other refinement you must include when performing in a cross wind. On the vertical climb up, the wind will have a tendency to swing the tail over, so the plane climbs in a crabbed angle instead of pointed straight up. To correct for this canted or angled position, you must hold some rudder all the way up the climb. Apply rudder "with the wind." That is, if the wind is blowing right to left over the plane in its climb, apply left rudder to keep the nose pointed straight up. Then, at the stall, apply right rudder to take advantage of the wind. Another challenge that can face you on this maneuver is a stiff headwind. Under such conditions the plan can "flop", usually backward, instead of rotating right or left. Flopping is embarrassing and annoying. The correction for this condition is to make your climb slightly off vertical. By hanging the nose slightly forward into the wind, you should have time to stall and rotate through the yaw axis without the wind flopping the plane onto its back. Especially when there is this strong headwind condition, but also for general good presentation of the maneuver, do your pull up upwind of yourself so the plane is viewed with the full top of the plane exposed, rather than pulling up in front of yourself and viewing the plane from its side. Any wind drift will be less noticeable if you do your pull up more upwind of yourself. If you are attempting this maneuver with a plane that rolls its main wing whenever rudder is applied, try offsetting that roll with application of aileron. Some planes as they complete their stall/yaw tur and start proceeding down the descent path, swing back and forth like a pendulum. In very advanced Pattern aircraft experimentation seems to show that putting anhedral in the horizontal stab minimizes the pendulum effect. I have found that getting off the rudder control too soon and too abruptly can contribute to the pendulum. So try relaxing rudder control more slowly. Next lesson we will get you used to flying upside down, including a chance to do a loop-starting and ending inverted!