Asymmetric Loads And Maneuvering Stalls

Almost any time the discussion is about stalling at greater than 1g, it usually involves symmetrical flight, where all portions of the airplanes structure are experiencing the same g-loading. But what if, say, one wing is at 2g and the other is at 3g, as might be the case in a rolling (banking) pull-up from a dive? The rising wing is experiencing greater g loading because its generating more lift. The descending wing, on the other hand, experiences less loading because its not generating as much.

Editorial Staff

Tuesday, August 25, 2015 at 12:00 AM ET

Verified

Key Takeaways:

Asymmetric loading, where different parts of an aircraft (e.g., wings in a rolling pull-up) experience varying g-loads, can cause the more heavily loaded part to stall first, potentially compromising structural integrity.
To prevent exceeding an airframe's load limits, high-g maneuvers like pulling out of a dive should ideally be performed with wings level.
Panel-mounted g-meters do not accurately reflect maximum loads during asymmetric conditions, so it's advised to limit asymmetric loading to 2/3 of the airframe's total load limit if unavoidable.

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Almost any time the discussion is about stalling at greater than 1g, it usually involves symmetrical flight, where all portions of the airplane’s structure are experiencing the same g-loading. But what if, say, one wing is at 2g and the other is at 3g, as might be the case in a rolling (banking) pull-up from a dive? The rising wing is experiencing greater g loading because it’s generating more lift. The descending wing, on the other hand, experiences less loading because it’s not generating as much.

That’s asymmetric loading, and the rising wing will stall first, because it will reach its critical AoA earlier than the other one. The structure will survive only if the maximum g experienced by any part of the airframe is less than the load limit. In other words, placing maximum loading on an airframe—by pulling out of a dive, for example—should only be done with the wings level.