Mastering the Stall Turn

Aug 07, 2013 No Comments by

MASTER THE STALL TURN

 

ILLUSTRATION BY FX MODELS & CHROME CITY STUDIOS

 

 

If you’ve been following my aerobatic columns during the past few months, I’m sure you’ve noticed that I’ve discussed many demanding extreme aerobatic maneuvers. This month, I’ll highlight the stall turn (sometimes also referred to as the “hammer-head”) in five steps. While this maneuver may seem fairly easy, it can be rather difficult to perform time and time again. Let’s begin!

 

 

THRUST-LINE SETUP

Before you attempt the stall turn, take a moment to ensure that the motor thrust is properly set on your aircraft. Sometimes, manufacturers build what is called “right thrust” into the aircraft’s motor box. When you view your model from above, the spinner and propeller should be on the fuselage’s centerline, but the propeller may be angled slightly to the right. If this is the case, your model has what is called “right thrust.” To test whether or not this amount is correct, fly your model on a calm day with little to no wind. Make sure the airplane’s wings are level, apply full power and pull to a vertical up-line. Then, release all inputs and pay attention to the aircraft’s tracking. If the model veers off to the right, too much right thrust exists. If the model tracks to the left, then more right thrust is required. Depending on how the motor is mounted into your particular aircraft, it may be as easy as adding a washer or two on one side of the motor mount. Properly trimming your model will ensure that your workload will decrease, so you can focus on one thing: performing the stall turn to the best of your ability!

The basic stall turn is performed by pulling the model to a vertical up-line. This º loop should be fairly gradual in radius and not be abrupt. Once the model is tracking on a perfectly vertical up-line, slowly decrease the power. Then, while traveling vertically and before the airplane comes to a complete stop, add rudder to pivot the aircraft 180 degrees. Now, let the aircraft track on the down-line. Lastly, perform a º loop to horizontal upright level-flight that matches the same altitude at which the maneuver began. It may be hard to believe, but this maneuver is not as easy to perform as it looks; here’s why:

When performing the traditional stall turn, you must ensure that the aircraft is tracking in a manner that is parallel to the runway and that the model’s wings are level to the horizon. If the wings are not perfectly level and you pull the stick back to perform the quarter loop to establish a vertical up-line, the model will be tilted. You’ll then need to apply rudder input to correct the model’s flight path. If this were a competition, points would be lost. All in all, make sure the wings of the model are level before attempting all aerobatic maneuvers.

EXECUTING THE STALL TURN

As with all new maneuvers, it’s best to perform at a high altitude until you are familiar with each move. In this example, we’ll perform the stall turn from left to right, parallel to the runway.

 

  • 1 Once you’ve determined that the model is flying parallel to the runway and that the wings are level, increase the throttle to full power and perform a gentle º loop to a vertical up-line. Please note, however, that attention must be given to the size of this º loop, as you will have to perform the same radius to exit the maneuver later in step 5.
  • 2 Now that the airplane is tracking perfectly vertical, slowly decrease the power. While the length of this vertical line is entirely up to you, remember that you do not want to make the vertical line very long, as the airplane may drift while on the up-line (this will require many small corrections). Also, if the vertical line is too short, the maneuver will look “rushed.” Generally, this vertical up-line should last about 3 to 4 seconds before the throttle is pulled back.
  • 3 Once the model is about to stop traveling on the vertical up-line, apply full rudder deflection. Tip: It is always best to stall the model (turn the aircraft) into the wind to ensure that the model will not “flop” over the top of the maneuver. Once the airplane pivots about 170 degrees, begin to release some rudder input. When the model pivots a complete 180 degrees, most of the rudder input should be released. Sometimes pilots find it helpful to hold a little rudder input a bit longer so the aircraft will not display the pendulum effect. Depending on the model you’re flying, you may find this helpful and/or required.
  • 4 The length of the vertical down-line should be the same as it was on the vertical up-line. The throttle should remain at idle until the exit radius has been started.
  • 5 To complete this maneuver, perform a gentle º loop that is the same size as the one performed in step 1. This way, the model will exit in a manner that is parallel to the runway. Remember, the airplane should also exit as the same altitude in which it entered the maneuver. Now you’ll see that the model is traveling in the opposite direction!

I wish you the best in performing this aerobatic maneuver and in all of your flying endeavors. Remember that your aerobatic success is not only a result of your flying skills, but also to your aircraft’s setup (mechanical- and programming-wise). Until next time, safe flying, and always remember to have fun!

Fixed-Wing Flight School, John Reid

About the author

West Coast senior editor About me: I’ve been involved with RC aircraft since high school and have flown just about everything. I started my RC career with scratch-building, but now like many pilots I rely on ARFs to get me in the air. My main focus is on pylon racing, aerobats, combat and scale warbirds.
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