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11.1 A Lesson on Snap Rolls
One fine spring day I was instructing a student who had about 5 hours experience. This was her first lesson in slow flight, but she was doing really well: she was maintaining the assigned altitude, the assigned heading, and the assigned airspeed (a couple of knots above the stalling speed). She was also doing a good job of keeping the inclinometer ball in the center, which required considerable pressure on the right rudder pedal because of the high power and low airspeed. I was really enjoying the flight, but suddenly I developed a feeling that there was something wrong. Gradually it dawned on me what the problem was. The problem was that the airplane was upside down.
Here’s what had happened: her right foot had gotten tired, so she just removed it from the pedal — all at once. This produced a sudden yaw to the left. Naturally the left wing dropped, so she applied full right aileron. The nose was dropping, too, so she pulled back sharply on the yoke. The next thing anybody knew, we were upside down.
I took the controls and rolled the plane right-side-up. (See section 16.21 for more about this.) We lost about 500 feet of altitude during the maneuver. The student asked “What was THAT?” and I said “That was a pretty nice snap roll”.
This is indeed the recipe for a snap roll: starting from a speed slightly above the stall, apply a sudden yaw with the rudder, apply opposite aileron, and pull back on the yoke. SNAP! — One wing stalls and the plane rolls over. In our case, we didn’t roll exactly 180 degrees — “only” about 135 degrees — but that’s upside down enough for most people. It took a fraction of a second.
11.1 A Lesson on Snap Rolls
One fine spring day I was instructing a student who had about 5 hours experience. This was her first lesson in slow flight, but she was doing really well: she was maintaining the assigned altitude, the assigned heading, and the assigned airspeed (a couple of knots above the stalling speed). She was also doing a good job of keeping the inclinometer ball in the center, which required considerable pressure on the right rudder pedal because of the high power and low airspeed. I was really enjoying the flight, but suddenly I developed a feeling that there was something wrong. Gradually it dawned on me what the problem was. The problem was that the airplane was upside down.
Here’s what had happened: her right foot had gotten tired, so she just removed it from the pedal — all at once. This produced a sudden yaw to the left. Naturally the left wing dropped, so she applied full right aileron. The nose was dropping, too, so she pulled back sharply on the yoke. The next thing anybody knew, we were upside down.
I took the controls and rolled the plane right-side-up. (See section 16.21 for more about this.) We lost about 500 feet of altitude during the maneuver. The student asked “What was THAT?” and I said “That was a pretty nice snap roll”.
This is indeed the recipe for a snap roll: starting from a speed slightly above the stall, apply a sudden yaw with the rudder, apply opposite aileron, and pull back on the yoke. SNAP! — One wing stalls and the plane rolls over. In our case, we didn’t roll exactly 180 degrees — “only” about 135 degrees — but that’s upside down enough for most people. It took a fraction of a second.
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