quote:

ORIGINAL: W37 Cepeda

I figured out how to stop the "EVERLASTING YAW SYNDROME"

This is what I call it know.. as you many of us have the pleasure
of seeing the DF37 in a unforgiving yaw spin with no end. No matter
the direction... and worst, the trim does not fix it.

After many hours of adjusting the servo shaft at both ends, still too
no resolve... I figured it out, so know I don't have do a mod on it.

The problem lies with the speed of the main rotors. Many of us
crashed DF37 and replaced the blades. But did you actually
verified the angle of attack? The angle on the blades that produces
the lift? Well.. the more angle you have, the more lift, but you
put more strain on the motor, and cut your battery fly time if you have to
much angle.....which by the way ..if you have more angle, your rotational
blade speed is lower, just enough to set your yaw outa wack if not
aligned properly. HENCE my solution for the problem with a belt drive.

So, picture this, and if you understand it.. you'll get it right away.

Cause of the mechanical aspect of the DF37, you will never, ever, and never, get
the DF37 to rotate counter clock wise " the same direction as the blades rotation"
by adjusting the trim or the servo rod, or
what ever you do unless you "SUPER MOD IT"...this only suppose to happen by inertia,
and ONLY WHEN HALF OR MORE THROTTLE IS GIVEN.

The rotation speed of the rudder blade is directly proportional to the speed
of the main rotors.

The way it works, is totally controlled by the Reciever unit.
In theory, there is a set MID point (throttle speed) at this stage, you
should have enough rudder to keep the DF 37 from drifting counter
clockwise. (hence were you should make your mecanical adjustment)

Second, when this point is passed (throttle up more), the receiver
will start to send a signal to the servo that controls the angle of the rudder
blades. The more throttle you give, the more angle of attack should
the rudder blades have. This is to compensate for the more rotational
inertia force manifested by the main rotor blades.

Because of the difference in the main blade angle of attack, from the mid
throttle point, to full throttle, the trims should be sufficient on alignment.

If your trim does not work, then your are very far from the MID point setting.

On my unit. I have the angle of the main blades to the point were at full
blast it won't fly.. I just want it light enough for it to hover on the training kit.

At full throttle.. when the DF37 nose is facing away from me, when I move the rudder
joystick to the left, it causes the DF37 to rotate counter clock wise.. it's very
responsive. But this happens not because the servo puts so much angle
on the rudder, as a matter of fact, it does not, it hardly puts some at all! You get it?
It takes very little at full throttle.

IF you get this right on MID point, the clockwise YAW will fall into place
on it's own. This is the way it should be. Hope this helps.