Auto-Rotation - GRAUPNER Ecureuil AS 350 Montage- Und Betriebsanleitung

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Ecureuil AS 350

8.10 Auto-rotation

This term refers to the flight of a helicopter without motor power. The rotational speed of the
main rotor can be kept high by setting both blades to negative pitch, and the airflow through the
rotor as it descends then keeps the blades turning. The rotational energy stored in the rotor by
this means can be converted into upthrust when the helicopter is close to the ground, by the
pilot applying positive collective pitch. Of course, this can only be done once, and it has to be
done at the correct moment. Auto-rotation allows a model helicopter to land safely when the
motor fails, just like a full-size machine.
However, auto-rotation places considerable demands on the pilot's judgement and reflexes; you
can only halt the machine's descent once, and you must not „flare" too early or too late. Much
practice is required to get it right.
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