RUDDER CONTROL:
What to do with your left hand while you’re flying

By BOB KARASCIEWICZ

Students typically do little with their left hands while learning to fly. Most of the throttle control is of the on/off type—on for takeoff and flying and off for landing. I’d like to tell you why you should use both controls on the stick.

Let’s start with a fun maneuver that uses both rudder and throttle. I call it the “tail wag.” Start with a nice, high and straight line (as all maneuvers are started) parallel to the runway. Have the throttle set to about half. As you go past yourself (the center), smoothly raise the throttle to full and let the airplane gain speed until it gets to full speed. Now it’s past you and going fast. Pull up to vertical and go straight up.

As soon as your airplane is going straight up, start moving the rudder stick side to side. Take roughly a second to do this; don’t stop until the airplane slows down and almost stops. At this point, push down elevator and resume level flight. Don’t forget to lower the throttle to approximately half and make your turn back. Did you see the tail wag? Wasn’t that cool?

Do it again. Each pass do the same thing and have fun. Now you are making the airplane do what you want! You’re using the rudder and it’s a ball. Let’s try something a little more complicated. If you practice these things, using the rudder will be just like using the ailerons. You’ll be doing it automatically.

The flat turn
Flat turn? How does an airplane turn flat? Everyone knows an airplane has to bank to turn. My instructor told me that when I was just starting out! Relax and everything will be all right. Since you are using the rudder, you can do more things with that beautiful trainer. Let’s try one.

First establish a nice high and straight line parallel to the runway. As I said before, most maneuvers start that way. Have the throttle set to approximately half again. Just before the airplane gets to the center (right in front of you), raise the throttle to full. The airplane will gain speed. As the airplane gets to the center and is going fast, slowly go to roughly half rudder (this stick movement should take about a full second). Use the rudder to turn the airplane away from the runway. If you’re going from left to right, give left rudder. If it’s going from right to left, give right rudder.

As you input the rudder, the airplane will start to do two things: roll and yaw (turn). At this point you will give opposite aileron to prevent the bank (roll). If you gave right rudder, give left aileron. If you gave left rudder, give right aileron. Move the aileron stick enough to keep the wings level. Depending on the wind, you will adjust the roll correction by adding or removing aileron input.
 

Students do little with their left hands
while learning to fly. I’d like to tell you
why you should use both controls on the stick.

To reiterate: If you’re going left to right at full throttle, give approximately half left rudder, and as the airplane starts to bank, use right aileron to keep the wings level. The airplane will be turning but not banking. You will only see the yaw. On aerobatic airplanes, when you give rudder, the airplane will do little or no banking.

This rolling as you give rudder is called roll coupling, and it has a lot to do with the amount of dihedral in the wing. This is not an aerodynamics column so I will not go into why. Hey, my airplane is turning without banking and I don’t know what to do next? Sorry, student!

Let’s get you out of the flat turn. When you have turned enough, just let the sticks (meaning both the rudder and aileron) go back to neutral. Please don’t just let go of the sticks. That “boing” drives me crazy, not to mention it will quickly wear out your transmitter as it will reduce the accuracy of your stick input.

Practice this stuff and while you are practicing using the rudder don’t forget to have fun. There is one danger you may run into while doing flat turns. After doing a 90° flat turn, you will no doubt want to do more. That is, you’ll want to complete a flat circle. They are really great and very impressive. Do them, but beware. The flat turn is a high drag maneuver. After all, you are forcing the airplane to go sort of sidewise. This causes more drag and speed goes down, causing less lift. Also, there is even less lift because of the sidewise airflow over the wing. Less lift means you could run out of lift. Running out of lift means a stall. Now don’t start worrying. You are nice and high, remember. If you do stall, release the rudder and aileron and return them to neutral, maintain full throttle and point the nose down a bit. As you gain speed, give a little up elevator and you will have full control as before.

In all, it’s no big deal. Stalling is part of flying. Actually, there is no need to even go that far. With today’s trainers you could do full rudder flat turns and multiple circles before you’d ever get into trouble. Okay, now let’s get to the really interesting stuff. We’re going to combine all you have just learned and do an amazing maneuver that you’ve seen and admired ever since you started coming to the field.

The stall turn
You know what to do. That’s right, high, straight, half throttle and parallel to the runway. As you pass the center of the field, you will go to full throttle and maintain heading at a high rate of speed. When you come to the place where you would normally turn around you will instead give full up. Go up straight, vertically, and at full throttle. After you have gone a few airplane lengths and your airplane has slowed down, lower the throttle to roughly one-third (keep it well above idle). As your airplane slows, give full rudder and after about a second, enough opposite aileron to keep the aircraft from rolling.

If you catch it just right, your airplane will turn flat within its own wingspan. Now you will be heading straight down. Release the rudder and aileron, raise the throttle to about half, and when you have gained some speed, return to level flight by giving up elevator.

One of the things that can go wrong is the aircraft flops over on its back or front. Recovery is the same. Most likely you were going too slow before giving the rudder. Input the rudder control sooner or don’t throttle down as much. If you still can’t catch this maneuver, you may want to talk to your instructor about increasing the throw of the rudder. Many trainers have very little rudder throw.

You may not catch the stall turn with a first try. Try it again! Don’t be afraid to go back to one of your instructors and ask for help. This can be a little tricky. You will be able to do this within a couple of tries.

If you are using a second airplane for this maneuver, you will probably have less roll coupling with the use of the rudder so be moderate with the use of the aileron corrections. At my club, we invite all soloed pilots to keep coming on training nights. There is plenty to learn after you solo. After all, we (as do most clubs) only require the most rudimentary maneuvers and takeoff and landing to solo. Most of your learning will take place after you solo.

from Ramblings
Roxbury Area Model Airplane Club
Michael Ramsey, editor
Flanders NJ