Determining Stall Point
Before we discuss how to find the stall point of a parachute, let’s define “stall point” and what happens to a parachute when it stalls.
The Stall Point of a parachute can be described as the point when the parachute is no longer producing lift. This is caused by an excessive “angle of attack”. Angle of Attack is often defined as the angle between the cord line (a straight line between the leading edge and the trailing edge of a parachute) and the Relative Wind.
When a Standard Ram Air Sport Type Parachute opens properly, its shape is typically rectangular or elliptical. The cells of the parachute are inflated with air. These cells will normally remain inflated as long as the angle of attack has not been exceeded.
A simple way to stall or exceed the angle of attack of a parachute while airborne is to pull down on both steering toggles at the same time until the parachute deflates or collapses.
It is important that skydivers be able to recognize when a parachute is approaching its stall point, how to stall, and how to recover from a stall.
To find the point where a parachute is approaching its stall point:
- Check to see that the parachute is working properly
- Check that you are clear of other traffic
- Check that your location and heading will allow you to land safely
- Check that your altitude (2500 feet the first time) is sufficient to recover
- With steering toggles in each hand, pull them smoothly down together while looking up at the bottom skin of the parachute. As you approach the Stall Point, the bottom skin of the parachute will start to wrinkle.
- Look to see where your hands are, this position should not be exceeded for the landing flare, to do so may cause the parachute to deflate or collapse
To Stall the Parachute – ( refer to above 1 thru 5 on approaching the stall point) then continue to pull down both steering toggles until collapse or deflation occurs. Standard 9 cell parachutes when stalled will normally turn initially, then with further deflation the corners of the tail will touch each other and the parachute will descend at a higher than normal rate.
To Recover a Stalled Parachute – smoothly return both steering toggles to the half brake position (Some high performance parachutes may have difficulty re-inflating properly once stalled due to severe self-induced line twist. Always check the manufacturer’s operating instructions before attempting to stall a parachute.) If stall recovery techniques are done too quickly, it increases the parachutes tendency to surge forward ahead of the skydiver. If this happens close to the ground, the parachute and the skydivers body can hit the ground at approximately the same time. This type of landing is normally refereed to as a Face Plant or Full Body Slam. It hurts.