Yaw control in a tandem rotor helo?

Richard Riley wrote:
I've been working with a conventionally configured helicopter for a
few months and this suddenly started eating my brain.

In a 2 rotor helicopter you are countering the torque of one rotor
with the other rotor. But how do you do a pedal turn? In a coaxial
I'd think you'd increase the pitch of once set of blades and decrease
the other. But what do you do in a tandem, like a CH-46? Increase
the pitch, you get more torque, but you also get more lift, so the
aircraft would move forward or backward -

Any helo pilots out there that can set me straight?

I have no clue if I am right but I always thought that stepping on the
pedals would be similar to a situation where you had a stick for each
rotor and moved them in equal and opposite directions. How that is done
mechanically I don't even want to think about.

--
Chris W
KE5GIX

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"Chris W" wrote

I have no clue if I am right but I always thought that stepping on the
pedals would be similar to a situation where you had a stick for each
rotor and moved them in equal and opposite directions. How that is done
mechanically I don't even want to think about.

I don't think so.

Banking a chopper with a stick tilts the mast because of the offset of
thrust on the one side. That causes the turn. To do so in opposite
directions with a tandem rotor would only try to twist the fuselage, and not
end up with any bank to cause a turn, assuming the you don't twist the
fuselage in two. g
--
Jim in NC

Morgans wrote:
"Chris W" wrote

I have no clue if I am right but I always thought that stepping on the
pedals would be similar to a situation where you had a stick for each
rotor and moved them in equal and opposite directions. How that is done
mechanically I don't even want to think about.

I don't think so.

Banking a chopper with a stick tilts the mast because of the offset of
thrust on the one side. That causes the turn. To do so in opposite
directions with a tandem rotor would only try to twist the fuselage, and not
end up with any bank to cause a turn, assuming the you don't twist the
fuselage in two. g

It also causes the vehicle to yaw into the turn. I still remember my
instructor yelling at me to press the outside peddle (quiet odd for a
fixed wing pilot to do in a turn).

-robert

"Robert M. Gary" wrote

It also causes the vehicle to yaw into the turn. I still remember my
instructor yelling at me to press the outside peddle (quiet odd for a
fixed wing pilot to do in a turn).

I thought we were talking about tandem rotor choppers, and how they managed
to do things like rotate (change direction they are pointed) in a hover.
No?
--
Jim in NC