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Old 04-21-2011 | 05:54 PM
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Gray Beard
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From: Hemderson, NV
Default RE: 1st tail dragger....(sigh)


ORIGINAL: opjose

For people who are having problems with yaw at run-up, I let the rudder have a decent amount of travel... somewhere between low and high rates... But not a full high rate... we want the rudder to be effective, but not overly so.

But I dial DOWN expo so it is NOT as ''soft'' or less responsive around center.

As counter-intuitive as that may seem, you have to remember that having a high expo rates ( or making things softer at center ) causes most of the rudder movement to occur at stick extremes...

So what happens with ''normal'' ( higher ) expo rate is that a novice will see a plane yaw, being used to light controls, they will move the stick a bit... nothing seems to happen to the yaw due to higher expo ( at soft center settings ) so they compensate by moving the stick a lot in a panic...

That causes a LOT of deflection moving the stick in the opposite direction very quickly... now they compensate AGAIN and move the stick the other way hard... and you get those typical YAW oscillations newbies often execute on their first tail draggers.

By making the rudder MORE responsive than what you have under normal Expo settings ( say around 15% instead of 30%+ people will dial in ), they tend to move the rudder less to get the corrective results they expect, thus avoiding the repeated overcorrection's....

This may seem strange but it works...
Just wondering/making sure I'm reading things correctly. Even on a trainer I use as much throw as I can get on the rudder and zero expo. The pilot controls the sticks so the travel doesn't mater as long as you have enough. I only remove about 40% of the throw for low rate anyway so if someone was having a problem with rudder on a plane I had set up they would still be having a problem on low rate rudder. I have tried using expo on the rudder but then I and or anyone flying one of my planes can get behind the plane too quick.