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It seems that yaw, more than pitch or roll, creates the greatest wing asymmetry in a spin. If the spin progresses to the point where it cannot be broken, some aircraft are equipped with parachutes to try to stop rotation and to get the nose pointed down. Some cannot be saved.

Tail rotors work well in helicopters, and are part of the design to control the (spinning wing) rotor yaw, and, such as the 180 knot MH-65 Dolphin, have the rotor built into the tail to save drag.

Could this work as a safety feature for GA aircraft?

Robert DiGiovanni
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    Probably unrealistic, think about the weight and complexity. Some sort of one-shot rocket pack might work, but probably better for deploying a recovery parachute. In some future fixed wing multi-propellor electric design you could more readily have distributed thrust but you're also more likely to see software that tries to prevent getting deeply into trouble in the first place. – Chris Stratton Jul 11 '19 at 15:11
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    That would be a monstrosity in search of a cause. Even airplanes not certified for spins will recover all by themselves, or with correct inputs, if you don't hold them in the spin for several turns. – John K Jul 11 '19 at 15:11
  • If? Perhaps if we had a number on the torque required to break a spin, an ELECTRIC (not rocket) may be possible. If reading about a Cessna 152 going flat (they really had to try) it was a thought. – Robert DiGiovanni Jul 11 '19 at 17:36
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    @Robert DiGiovanni: Re "they really had to try", why add weight and complexity to airplanes in order to try to save a very few idiots from the consequences of their own stupidity? – jamesqf Jul 11 '19 at 17:55

2 Answers2

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At least one of two possible devices is regularly added before spin testing:

  • Jettisonable mass, for example by fixing a sandbag to the tail, or
  • a spin chute.

Spin chutes do what you propose in yaw, but what they mostly do is to pull the tail up so the angle of attack over the whole wing is reduced. This is equally achieved by jettisoning that extra mass at the tail: Now the more forward center of gravity will add a nose-down moment.

In both cases the lowered angle of attack restores roll damping on the wing. This is really what stops a spin, yaw is less of a problem here.

Peter Kämpf
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Theoretically possible, but major weight and drag penalties for a very rare even. I have worked certification. Of several airliners and we always used an anti spin parachute. But only on a prltotype,the one dedicated to stall development.. Most programmes if a stall protection system is required may need up to 3000.. or more stalls before certification..And yes wings will drop at the stall and perhaps authorisation into a spin will start ... .. But we develop the stall.prove tion system to give the customer pilot's margin ... While not impacting performance.

david innes
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