Explaining anti-servo tab

gomntwins

Well-Known Member
Does anybody have a good way to explain how an anti-servo tab works. I know how it works in my head-- I just can't think of a good way to teach it... anyone with any ideas? thanks!
 
I always just tell my students that servo tabs "serve" the pilot by helping him or her move the large control surfaces. While the anti-servo tabs do just the opposite by making the surfaces harder to move.

(it is kind of dorky, but seems to work)

Once they understand what the function of each is, you can go into the detail of the movement of each tab through the control deflections.

-Also, don't forget fixed and balanced trim tabs.
smile.gif
 
I embarrassed myself in front of a student today while trying to explain this very topic. I explained that anti servo tabs help you move the stabilitor because they were too heavy otherwise. My student said "hey, I thought they added resistance because the stabilotor has too much of a loose feel without them". I just kind of nodded my head and said "yeah, that too" and moved onto the next part of the preflight.

Then it took us 4 tries to start the engine, thought we were going to need ground power. Then the intercomm wouldn't work so we had to use "one ear" of our headsets and shout through the cabin to communicate with one another. Ahhh, the joys of instructing in a plane I have 1.8 hrs total time in.

I asked some other CFI's after the flight and they told me the student was correct. How I got this far without knowing how anti-servo tabs work, I'm not quite sure.
 
Here's a good site to visually show what happens for Servo and anti-servo tabs (along with the other controls too)

Demo

What were you instructing in? (just curious)
 
[ QUOTE ]
I always just tell my students that servo tabs "serve" the pilot by helping him or her move the large control surfaces. While the anti-servo tabs do just the opposite by making the surfaces harder to move.

(it is kind of dorky, but seems to work)

[/ QUOTE ]I do the same as you, except I explain that in both cases, they help the pilot move the control surfaces. The servo tab helps you move them when they're aerodynamically "heavy"; the anti-servo helps you move them under control when they're aerodynamically "light".
 
[ QUOTE ]
[ QUOTE ]
I always just tell my students that servo tabs "serve" the pilot by helping him or her move the large control surfaces. While the anti-servo tabs do just the opposite by making the surfaces harder to move.

(it is kind of dorky, but seems to work)

[/ QUOTE ]I do the same as you, except I explain that in both cases, they help the pilot move the control surfaces. The servo tab helps you move them when they're aerodynamically "heavy"; the anti-servo helps you move them under control when they're aerodynamically "light".

[/ QUOTE ]

Good point.
 
One other thing the examiner I did my commercial ride with stressed was that the anti-servo tab is designed to help prevent pilot-induced oscillations (by making full-scale deflections difficult).

-Zach
 
[ QUOTE ]
I embarrassed myself in front of a student today while trying to explain this very topic. I explained that anti servo tabs help you move the stabilitor because they were too heavy otherwise. My student said "hey, I thought they added resistance because the stabilotor has too much of a loose feel without them". I just kind of nodded my head and said "yeah, that too" and moved onto the next part of the preflight.

Then it took us 4 tries to start the engine, thought we were going to need ground power. Then the intercomm wouldn't work so we had to use "one ear" of our headsets and shout through the cabin to communicate with one another. Ahhh, the joys of instructing in a plane I have 1.8 hrs total time in.

I asked some other CFI's after the flight and they told me the student was correct. How I got this far without knowing how anti-servo tabs work, I'm not quite sure.


[/ QUOTE ]

I learn new stuff all the time. Sometimes, I wonder how I got as far as I have without knowing some of the things, but I guess thats the way it goes. Regardless, if there is a doubt on something like this, I always say "you may be right, but let me, or lets look it up later and be sure." I always go back to the student and tell them "you were absolutely right on that topic" or "you were close, but here is what I found out."

Thanks for the link to the demo too!
 
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