Stalling an Airplane

Several of you have talked to me about the stall tests of my airplane so I figured that I ought to do a short video and show you what is involved. Stalls are not anywhere near as exciting as they sound, certainly nothing like the way that Hollywood depicts them.

Let’s start with a tiny bit of physics. Stay with me. It won’t be much; I promise.

When air flows over the wing of an airplane, it generates lift. The faster the air flows, the more lift. My airplane weighs 1,700 pounds with full fuel and me aboard. When the air flows over the wing at about 65 knots (nautical miles per hour) which is about 75 MPH (statute miles per hour) then the wing generates more than 1,700 pounds of lift and the airplane flies. Any speed less than that and the airplane won’t fly.

Let’s pretend that the airplane is only flying at 60 knots. It still generates a lot of lift; certainly not zero. But since it is less than 1,700 pounds, the airplane sinks through the air. This is a “stall.” It means that the wing is not producing enough lift to maintain altitude. The airplane does not fall out of the sky; it just sinks or flutters down, kind of like a leaf falling out of a tree.

There is one more thing to know. When an airplane stalls, it is designed so that the nose drops toward the ground. This makes the airplane “go downhill” and pick up speed and then it starts flying again.

I performed 11 stall tests on March 21, trying different configurations of the flaps and repeating tests so that I would have a solid understanding of how the airplane behaves. Here is a video that I made of one of the tests.

If you are a data nerd, you might like these two graphs. In the first, you can see that, during the stalls, the airplane only descends a few hundred feed. The vertical speed shows a startlingly large spike downward but only for a few seconds and then the airplane recovers and is flying again.

This second graph shows pitch angle (how far the nose tilts up or down) and airspeed. You can see that the nose only points down about 10 degrees in most of the stalls (including the one in the video above).