Flight control paint

brien23

brien23

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Brien
How much is too much paint on a flight control before you have to balance it. If you do a little touch up paint does that require a new balance to be done. Just how much is too much and require you balance the flight control. I am sure their are planes around that have not been washed in years with dirt and grime over the flight controls that could cause them to be out of balance. If you guess it wrong and the flight control starts to flutter then it's too late.
 
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I’ve never seen an aircraft painter who did anything about balancing. I don’t think paint is a factor for my plane given that I know guys with like airplanes who’ve removed paint and polished the aluminum with no consequence. I think balancing controls is more of a design engineering thing.
 
Depends on how the control is built, how much area is redone and how thick the paint is. Fabric covered and more area than about 3”x3” and I’ll pull and check. Aluminum skin and more than about 6”x6”, I’ll check it.
 
Stewartb said:
I’ve never seen an aircraft painter who did anything about balancing. I don’t think paint is a factor for my plane given that I know guys with like airplanes who’ve removed paint and polished the aluminum with no consequence. I think balancing controls is more of a design engineering thing.
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Cessna, Piper and Beech, among others, have sections in their maintenance manuals that cover control balancing. Flying with a control surface such as a stabilator that it out of balance wouldn't be very smart.
 
The bigger point is that paint apparently isn’t a factor, at least with my plane. If a guy was concerned about maintaining balance touching up paint would be good practice. I have a buddy with an exp Cub that was getting some aileron flutter at full speed. I talked to another friend who’s very familiar with aerodynamics who offered some solutions, like adding lead to the aileron leading edge, adding spades, or blunting the trailing edge. Interesting stuff, but way beyond paint being a contributing factor.
 
When I designed my paint scheme, I kept the control surfaces mono color, only my flaps are 2 tone and no stripes. Painter said my surfaces were all in the mid range.
 
You may want to google “ Commanche Tail Flutter”.
 
We balanced them after painting. Sometimes we found them right on the margins. Any repairs to the sheet metal and for sure they should be checked.

Faster airplanes are much more critical this way.
 
Beaver in Alaska in 2005 experienced flutter, destroyed the airplane.
I am dropping my SkyWagon off for paint on Friday, we are taking all the control surfaces and fin off. They will all be checked for balance before installation. It is the correct to balance a flight control after it has been repaired or painted. The window for balance is pretty large, but who knows if some idiot removed the weights trying to lighten the plane at some point?
 
brien23 said:
How much is too much paint on a flight control before you have to balance it. If you do a little touch up paint does that require a new balance to be done. Just how much is too much and require you balance the flight control. I am sure their are planes around that have not been washed in years with dirt and grime over the flight controls that could cause them to be out of balance. If you guess it wrong and the flight control starts to flutter then it's too late.
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Since no one knows how close to limits your control surface is and has no idea how much paint you are going to use, no one can answer that question.
 
My plane is experimental and the ailerons are balanced. I did the balance before painting & after and they stayed within the margins called for by the kit supplier. It's easy to think that a coat of paint won't make a difference; but it *might* ...
 
It is plane specific. In my airplane only the ailerons are balanced…
 
Wagondriver said:
Beaver in Alaska in 2005 experienced flutter, destroyed the airplane.
I am dropping my SkyWagon off for paint on Friday, we are taking all the control surfaces and fin off. They will all be checked for balance before installation. It is the correct to balance a flight control after it has been repaired or painted. The window for balance is pretty large, but who knows if some idiot removed the weights trying to lighten the plane at some point?
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Make sure they give you a log entry that states they balanced all flight controls. I would ask them to write directly on the flight controls what they balanced at and the date they were balanced with a sharpy marker, somewhere it can be seen when inspecting them such as:

"XX ounces under/over balance on DD/MMM/YYYY"

For obvious reasons more complex aircraft have maximum weight limits of fully assembled and balanced surfaces as well, if that applied I would want that written on them as well.
 
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Wagondriver said:
. The window for balance is pretty large, but who knows if some idiot removed the weights trying to lighten the plane at some point?
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We found one aileron with insufficient weight for balance. A legacy Cessna which would have been originally painted with lacquer, a really lightweight coating. After the airplane was refinished with epoxy primer and urethane topcoat, that aileron was just outside the limit. We had to add a bit more lead to it. It was likely just within tolerance when it left the factory, but the nice new tough wet-look finishes are much heavier than lacquer.

And no, the aileron wasn't full of crud. We cleaned all that out of all the surfaces during paint stripping. I've seen old stripper and paint inside places like that. Not good. Some airplanes get stripped and repainted without removing anything other than the plastic fairings and maybe the inspection covers, a practice guaranteed to blow paint and stripper into whatever places it can get.
 
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