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Bill A

The use of Yaw Dampers

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Question, what are yaw dampers used for, and should they always be turned on? Some aircrats then turned on during taxi have the rudder going left and right in a crazy manner even when the aircraft is not moving. I have always kept them off.Thanks,Bill

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Hey Bill, the yaw dampers are in essence a coordinated rudder. It dampens the adverse yaw encountered in flight when you make a turn, especially in FS9, as you don't need to use rudder input in some aircraft. After you line up on the runway,turn it on and leave it on until after you have landed and are getting ready to turn off the runway. Some pilots forget to turn it off right away, but this is what it is there for. I hope this helps.

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depending on the airplane/pilot/company they are either turned off before taxing or after takeoff. I think the older airplanes only use yaw dampers after takeoff and switched off before landing while new ones like the -400 have them on all the time

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Yaw dampers have practically no effect on the ground. "The prime function of the system is to minimise Dutch Roll by providing automatic rudder displacement proportional to and opposing the amount of yaw experienced."http://www.boeing-727.com/Data/systems/infoyawdampers.htmlA Dutch Roll is a form of lateral instability involving out-of-phase roll and yaw. It's rarely found in light aircraft but can frequently occur in swept-wing aircraft at altitude. When they are switched on is basically a matter of company operating policy. They do no harm if switched on outside the Dutch Roll regime so it's generally better to have the switched on most of the time.Don't confuse the Dutch Roll instablity with the deliberate manoeuvre also, confusingly, called a Dutch Roll. This involves rolling the aircraft from side to dide while applying rubber to keep the aircraft pointed in the same direction.

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>>Hey Bill, the yaw dampers are in essence a coordinated rudder. It >>dampens the adverse yaw encountered in flight when you make a turnActually, that is not the purpose of the yaw dampers. Many transport aircraft have varying degress of stability at different speeds, especially spiral stability. This means that they can be prone to get into Dutch Roll situations, the yaw damper is intended to prevent dutch roll, rather than cure it.Most aircraft have then turned off at t/o and approach, because in these low speed conditions with high engine power, the yaw damper may hinder the pilot in controlling asymetric yaw effectively and quickly. I guess later aircraft have in-built logic such that when TOGA is engaged, the yaw damper is automatically inhibited or something.Edited: Oops, mgh beat me to it.

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Most aircraft allow yaw dampers to be on all the time.The DF727 and RFP747 need to have them off for landing, because yaw dampers are limited in travel (to prevent the yaw damper from causing a wreck in case they flip out). With yaw dampers on, I've found that the DF727 and RFP747 could roll off the side of a runway because you couldn't get the rudder to function fully.Contrast that with the Flight 1 MD80, where a blue message appears close to touch down that says something like "full rudder available" i.e. I believe the yaw damper is operating in a different mode or shut off.One phrase I've heard: "Wheels down, yaw damper off" I use that for the DF727 and RFP747.

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