Secondary Effect of Ailerons

Secondary effect of ailerons is adverse yaw.

In this lesson, we will demonstrate the secondary effect of the ailerons.

Learning Points

We have seen already that the ailerons are used to roll the glider. The instructor cheated a little in the previous demonstration, as she was applying a co-ordinating rudder movement. What happens if we use the ailerons on their own? It depends to some extent on how quickly we are flying.

When flying slowly, and rolling without rudder, the glider will initially yaw markedly in the opposite direction as it slips into a badly coordinated turn in the direction of the roll (watch the string flick away from the turn!). This effect is called ‘adverse yaw’ and is a result of aileron drag on the upgoing wing.

When flying more quickly and rolling without rudder, the yaw effect is less marked, but a sideslip will be seen in the turn (check the string).

If we use the aileron and rudder together, we can make a coordinated turn, meaning there is no yaw as we turn. This is confirmed by seeing the string point backwards at all times

Demonstration

This demonstration is not the way to fly! Your goal is always to fly ‘coordinated’, using matching aileron and rudder movements together. This shows what happens when you apply aileron without coordinated rudder.

What happens when you use aileron without rudder?

Alternative Video without animation.

Secondary effect of ailerons, as seen in Condor’s Flight School
About the videos

Multiple versions of the videos are being made available:

  • With animation and voiceover.
  • Alternative without the animation graphics.
  • As recorded in Condor Flight School. These will have messages at the top of the screen, with no additional animation or voiceover – that’s the way the Condor cookie crumbles!

The videos are suited to any device that supports YouTube. If you have trouble loading the video in the browser, click on Watch on YouTube in the lower left corner.

Further Reading and References

Gliding From Passenger to Pilot, 2nd Edition: Pages 35-36, 88

BGA Instructors’ Manual, 4th Edition: Section 2, Chapter 7, Page 7-3

BGA Instructors’ Reference Cards: Ex 6

BGA Gliding Basics – Effects of Controls