When flying backwards you have horizonal and vertical tail surfaces
flying backwards. As long as they are aligned perfectly into the
relative wind every thing is ok, however this is not a stable
condition. They want to fly BEHIND the aircraft. When a slight
offset occurs it will get larger fast as the tail tries to turn around
so that it is again behind the helicopter which is stable. If you do
the pedal dance correctly you can keep the error small and you will
have enough tail rotor power to keep the tail pointing into the wind.
If you screw up and let the error get too large the tail will come all
the way around because there is not enough tail rotor power to stop
the turn. The worse problem occurs when the tail tries to go up or
down to realign. This will force the tail into the dirt or the sky,
both are bad. If the tail goes up it may lead to a tail boom strike
by the main rotor. If down the tail rotor eats dirt.
John

On Sat, 15 Jan 2005 04:33:16 GMT, John Doe
wrote:

I recall hearing mention of something like this before. While doing a
simulation, probably moving backwards, the helicopter tale began
swaying back and forth uncontrollably.

Is that the way it is in real life?

How do you get out of that? Avoid moving backwards?

Besides trying to tilt the chopper forwards, is there anything to do
when the gyrations first began? When gyrations become extreme, is there
any way out? I suppose structural damage is possible?

Thank you.