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Is it possible to control the direction during auto-rotation, and how does it work?

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If you forget the fact that you are only ever going to go down (ignoring that in some types you might be able to go up for a short time) many helicopters are delightful to fly in autorotation. You can fly forwards, descend straight down (0 kts) or even fly backwards - although most pilots find the latter really uncomfortable. –  Simon Apr 11 at 22:14
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It's entirely possible.

Attitude control works the same way during autorotation as it does during normal powered flight. It's a good thing, too... during an autorotation you want to target your descent toward a suitable landing spot :-)

To (say) roll right, moving the cyclic causes the swashplate to move in such a way that the rotor blade's pitch (angle of attack) is greater during the left-side portion of the blade's travel, and lower during the right-side portion. This produces more lift on the left side, which causes a right-rolling moment on the helicopter.

The fact that the collective is all the way down and that the rotor's RPM is being maintained by airflow through the rotor does not change the way the cyclic produces attitude changes.

The anti-torque pedals still work too, although during an autorotation the pilot will promptly apply full right pedal, since lowering the collective will essentially eliminate torque from the rotor. Pedals can still be used for yaw though, as the tail rotor is still spinning (it is linked to the main rotor).

The "180° turning autorotation" is a common maneuver taught in basic training, where the pilot must set up the autorotative descent and then complete a 180° turn toward a landing spot.

For more information about autorotations in general, I recommend the FAA's (free online) Helicopter Flying Handbook. See page 2-24 for a general description, and page 11-2 for procedures/technique.

There are also lots of autorotation demonstration videos on YouTube that show maneuvering to a landing spot / 180° turns during the auto.

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Thanks, that sounds pretty exciting, especially the part about the tail rotor. Now, i'm asking myself, what would happen if i had no tail-rotor (i.e. i'm sitting in a gyrocopter), would i start to spin? –  Hannes Apr 11 at 15:03
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@Hannes: Gyrocopter, better known as autogyro, always autorotates. It has normal rudder for directional control, which is sufficient, since autorotation produces very little torque. –  Jan Hudec Apr 11 at 18:21
    
@JanHudec; I think "better known as" might depend a little bit on where you are. If I'm not mistaken, they're usually indeed called "gyrocopters" over here. Cool point about them always auto-rotating, never thought of it that way. –  falstro Apr 12 at 7:29
    
@falstro: The wikipedia page is titled Autogyro and mentions autorotation as defining feature in the first sentence. –  Jan Hudec Apr 12 at 20:27
    
the pilot will promptly apply full right pedal, depends of course on which way the top is spinning. You've assumed counter-clockwise. Doing that in a clockwise spinner will result in an underwear changing "unusual attitude". –  Simon Jul 14 at 23:57
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