The ball is not centered

Salty

Salty

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Salty
ok, What could cause a turn coordinator to have the ball sitting centered on one of the lines instead of between them when sitting on flat, level ground?
 
Most of the ones in our club lean slightly to one side. I always just assumed it was because either the gauge is not centered correctly (the screw holes on ours have a "range" for centering) or that the oleo struts are uneven.
 
eman1200 said:
A broken turn coordinator?
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How can a tube full of liquid and a ball be broken ( when they aren’t actually broken, if you know what I mean)
 
Tantalum said:
Most of the ones in our club lean slightly to one side. I always just assumed it was because either the gauge is not centered correctly (the screw holes on ours have a "range" for centering) or that the oleo struts are uneven.
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It’s almost a ball width off. That seems more than an a minor adjustment
 
Salty said:
How can a tube full of liquid and a ball be broken ( when they aren’t actually broken, if you know what I mean)
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I dunno. That’s why it was a question and not a statement*

“How can a tube full of liquid and a ball be broken”......I’m not getting man touch that one.....
 
The ball seeks the lowest point in the fluid filled tube (thanks gravity), so there isn't a failure mode I can think of other than what Tantalum suggests.
 
Salty said:
It’s almost a ball width off. That seems more than an a minor adjustment
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Yeah that's peculiar. Although like you said that tube and ball can't really "break" - it's probably the simplest instrument in the plane (along with the compass). Dumb question, but, are you sure the plane itself is sitting level? You could grab a tape measure and measure the distance from the ground to the wing tip on each wing. If the numbers are off then the plane is not level (mlg strut issue?). Otherwise, if you get similar or identical numbers, then somehow the gauge itself is not in the panel centered (assuming the ground is level)

My $0.02.. or whatever you paid for it
 
There’s a procedure for making sure the airplane is truly level, and then there’s a mounting screw hole that’s a slot instead of a round hole, for loosening it and twisting the instrument until level is indicated on the ball.

On probably 3/5 airplanes I’ve flown, the stupid thing isn’t truly level when the plane is level.

Probably because some shop somewhere thinks their shop floor is level or that one tire isn’t low on the airplane, and they don’t measure. They just slap the thing in and call it good.

Ours is ever so slightly off level to the left. It’s tiny but after you do a few hundred hours in the thing, you know. Such a small amount that messing with it would probably just make it worse though.

Another reason they don’t get quite right. :)
 
Salty said:
ok, What could cause a turn coordinator to have the ball sitting centered on one of the lines instead of between them when sitting on flat, level ground?
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Research where/how the OEM levels the aircraft to weigh the aircraft. Sometimes they use a spirit level across/parallel the seat rails. Compare leveled aircraft attitude to your indicator. Sometimes the world is off a bit.
 
The plane is noticeably out of coordination if you center the ball.
 
Salty said:
The plane is noticeably out of coordination if you center the ball.
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That can also be rigging. You set the ball by leveling the aircraft. If it’s flying crooked after that, something else is wrong. Many do.

The process for rigging is a lot more involved than getting the inclinometer level.
 
The ball is installed off level. Level the ball to a leveled aircraft. Make sure you understand level aircraft means. It isn’t the same thing as static.
 
Another factor that comes up is with panels that have shock mounts on them, after awhile those rubber shock mounts start sagging too. Your plane can be perfectly level but those old mounts can throw the instruments off.
 
Tantalum said:
Dumb question, but, are you sure the plane itself is sitting level? You could grab a tape measure and measure the distance from the ground to the wing tip on each wing. If the numbers are off then the plane is not level (mlg strut issue?). Otherwise, if you get similar or identical numbers, then somehow the gauge itself is not in the panel centered (assuming the ground is level)

My $0.02.. or whatever you paid for it
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A point on each wing being the same distance from the ramp does not prove the aircraft is level.
 
What if one had two balls, how ya level them? :popcorn:
 
Get some clear plastic tubing, enough to reach wingtip to wingtip and a few feet more. Fill it with water. Get another person and hold a point a few inches in from the end to the same point on each wingtip. Dribble out some water until the water line on one side is right at the chosen point on one of the wings. If it’s not at that point on the other one, let some air out of one tire until it is. Or use a ratchet tie down, sandbags, whatever to level the Wings. Don’t do anything to compress the tire or landing gear after that. Get a level with a good bubble. To check this find a flat surface, doesn’t have to be level, just flat. Put the level on it and check the bubble. Now ‘spin’ the level 180 degrees and put it down on the same spot. If the bubble looks exactly the same, you have a good bubble. Put it across the seat rails. If they aren’t level you have some issues other than just your ‘ball’ being off. If they are level, now adjust the ball until it is centered. If the wingtip to wingtip level and the seatrail level don’t match I suppose you could ‘average’ them to set the Ball. Maybe just setting it to the ‘wings level’ would be the best
 
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it’s a rental so I won’t be fixing it. Was just curious.
 
Tantalum said:
Yeah that's peculiar. Although like you said that tube and ball can't really "break" - it's probably the simplest instrument in the plane (along with the compass). Dumb question, but, are you sure the plane itself is sitting level? You could grab a tape measure and measure the distance from the ground to the wing tip on each wing. If the numbers are off then the plane is not level (mlg strut issue?). Otherwise, if you get similar or identical numbers, then somehow the gauge itself is not in the panel centered (assuming the ground is level)

My $0.02.. or whatever you paid for it
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It's easier to simply lay a long level across the fuselage (at the proper place) Then adjust the instrument, the mounting screws allow this.
 
Salty said:
ok, What could cause a turn coordinator to have the ball sitting centered on one of the lines instead of between them when sitting on flat, level ground?
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As mentioned, I think it's instrument not installed correctly. After getting my G5 AI I noticed that the ball in that and the old school one in my T&B didn't depict the same. When adjusting the rudder trim/yaw damper to center the ball on each one in cruise I noticed that I picked up a couple mph's if the G5 ball was centered and the T&B was a little off. They leveled the plane when they installed the G5.
 
Quit making excuses and get on those rudder pedals rookie ;)
 
The inclinometer is like the pendulum - it measures lateral forces in the airplane. A centered ball means you can hold a glass full of water, and it won't spill. However, I've flown in airplanes where centering the ball with wings level would actually make the airplane turn slightly. To put it differently, straight coordinated flight could be achieved only with the wings slightly banked. This indicates a problem with the air frame. It can be due to a number of reasons, such as slightly unequal drag from the wings, or one wing being heavier than the other.
 
sarangan said:
The inclinometer is like the pendulum - it measures lateral forces in the airplane. A centered ball means you can hold a glass full of water, and it won't spill. However, I've flown in airplanes where centering the ball with wings level would actually make the airplane turn slightly. To put it differently, straight coordinated flight could be achieved only with the wings slightly banked. This indicates a problem with the air frame. It can be due to a number of reasons, such as slightly unequal drag from the wings, or one wing being heavier than the other.
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Yep, or out of rig, or inclinometer installed out of level. As a general rule a level inclinometer is the first thing I look for, it's easy enough to do, and only takes a few minutes.
 
You know you don’t even need to bust out any special tools to get a quick check to see if the stupid thing is right on the ground.

A piece of string and something tied to the end of it as a weight held in front of it will tell the gross adjustment tale.

Use your headset cable if you’re strapped for a tennis shoe string. LOL.
 
denverpilot said:
You know you don’t even need to bust out any special tools to get a quick check to see if the stupid thing is right on the ground.

A piece of string and something tied to the end of it as a weight held in front of it will tell the gross adjustment tale.

Use your headset cable if you’re strapped for a tennis shoe string. LOL.
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That reminded me of a time I had to find true vertical on an offshore drilling rig. Gravity works.
 
bluerooster said:
But proves it's level with the slope of the ramp.
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Not level. Parallel, yes. But neither the ramp or the wings are ‘level,’ anymore than a building next to and ‘even’ with the leaning Leaning Tower of Pisa is ‘plumb.’
 
Almost all planes are a little out a rig. But it's fun to try. Write down what u d so u can undo it
 
Put it in level flight, take your feet off the rudder pedals. Look at the horizon. What happens?
Get out a screwdriver or allen wrench and fix it.
 
To test it in-flight, find some smooth air, make the wings level, (use a reference in front of you, like the top of the instrument panel) and while the wings are perfectly level, find a point straight ahead as far out on the horizon as you can see and with slight rudder pressure keep the airplane pointing straight at it - in other words, aim the airplane like a rifle, while keeping the wings exactly level. Then glance at the ball (it should be centered). If it’s not, loosen the mounting screws and adjust the instrument til it reads correctly, tighten screws.
 
j1b3h0 said:
To test it in-flight, find some smooth air, make the wings level, (use a reference in front of you, like the top of the instrument panel) and while the wings are perfectly level, find a point straight ahead as far out on the horizon as you can see and with slight rudder pressure keep the airplane pointing straight at it - in other words, aim the airplane like a rifle, while keeping the wings exactly level. Then glance at the ball (it should be centered). If it’s not, loosen the mounting screws and adjust the instrument til it reads correctly, tighten screws.
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Makes sure to do it with only one wing full of fuel, too. :) :) :)
 
I had this problem, I asked the mechanics to fix it when it went in for annual. They did, said it was a simple adjustment.
 
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