Paragliding ABC
Vocabulary
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Glide: 9.0 : 138.6 Km/h0.010.020.030.040.050.060.070.080.00.010.020.030.040.050.060.070.080.0Air SpeedGround Speed0.0-0.2-0.4-0.6-0.8-1.0-1.2-1.4-1.6-1.8-2.0Stall PointMin SinkTrim SpeedTop SpeedBest Glide
Wind Speed: 0.0 Km/h
mph
Km/h

Lesson 1 - Introduction

The vertical axis on the left is sync speed, in m/s.

On the top there are two horizontal axes, one for glider air speed, and another for glider ground speed. With no wind, the two axes are in the same position. You can switch between Km/h and mph.

The polar curve is the set of points in this plane that are possible for the glider. Position on the curve depends on the braking or acceleration controls the pilot engages.

In this simulation the wind is aligned with the glider direction, that is headwind or tailwind. Other configurations, like lateral or cross wind or vertically moving air (lift/sink) - maybe in a future version.

Lesson 2 - Identify key points

Identify the key points on the polar curve. Click the labels of each point on the graph.

  • Stall Point: from this point, if you apply any more brake, the wing will stall.
  • Minimum Sink: at this level of braking, the glider sinks the slowest.
  • Trim Speed: the speed you get when you apply no brake and no speed bar.
  • Top Speed: the maximum horizontal speed - speed bar is fully pressed.
  • Best Glide: the configuration that gives you the best glide ratio - you glide furthest.

Lesson 3 - Wind speed effect

Change the wind speed to see how it affects best glide.
A negative value is headwind, positive one is tailwind.
Notice how the air speed X axis moves together with the polar curve.
If the air moves, the glider still flies the same relative to the air, but the ground speed is different.

The glide ratio indicated is for the ground speed, this is the one that you care about.

Lesson 4 - Headwind

You have a headwind of 15 Km/h
See how best glide position has moved lower and to the right on the curve.

For best glide you now apply some speedbar.

You will sink faster but with greater horizontal speed.

Lesson 5 - Tailwind

You have a tailwind of 15 Km/h
Apply some brake to improve your glide.

Lesson 6 - Same gide at min sink and trim speed

For this particular glider, at 21 Km/h tailwind, the glide ratio at minimum sink is the same as at trim speed.
The best glide is somewhere in the middle of the two.