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Immediately Re-balance Elevator After Painting?

schaplerrh

Well Known Member
Sponsor
Looking for knowledgeable guidance: I've finally gotten around to having my RV7 painted after several years of ownership (I'm not the builder). The builder did a precise job of balancing the tail feathers planning to leave them polished metal. They are now painted but I'm wondering if I need to have the shop re-balance the elevator before I pick up the plane or can it wait until I flew it home so I can do it myself. The paint shop is obviously experienced with this kind of thing so I've no doubt the job will be done right by the shop. My real concern (maybe that's too strong a word) is the safety of the flight home if I wait and do the re-balance myself? Perhaps put more precisely, is it likely that the painted elevator is dangerously out of balance (i.e., does paint add that much weight). Van's support isn't specific, just says should be balanced (but doesn't say or even imply immediately).

Looking forward knowledgeable guidance.

Thanks all,
Robert
 
Hi Robert,

The paint moves the balance aft, so a rebalance should be done. And, each elevator should be balanced individually (per Van's), not as a connected unit. The left usually needs more weight than the right. I had the shop balance after paint, and then I rebalanced it, a few weeks later - the left side needed quite a bit more weight. I did not exceed about 150ktas, until I rebalanced it.

Merrill
 
Rememebr that you balance control surfaces to prevent flutter, and flutter only has to happen once to ruin your whole day (and/or your whole life). Usually, aircraft manuals (and good practice) say that you must rebalance control surfaces after painting - not within so many hours of flying time after painting. If your surfaces were perfectly balanced before paint, then they are, by definition, out of balance afterwards, and you should balance them before further flight.

No, they probably won’t flutter on a flight home….but they might, and that can kill you. Paint shops should know how to balance them, although with an experimental, they might want the builder’s help since they can’t consult a manual, like they would with a Cessna or Piper.


Paul
 
Please educate me

My RV3 is very heavy on the elevator built to plans. So, help me understand the difference between a heavy elevator and a “ not fully counterbalanced elevator” with regard to flutter.
 
Control Surface Balance

Yes, before flying check and rebalance whenever anything is done that might change the weight. Paint certainly can do it since there is a lot more area aft of the hinge line.

Don Broussard A&P, IA, ATP
RV9 Rebuild in Progress
57 Pacer
 
Before anyone gets carried away cutting open elevator horns, perhaps a call to Van’s is in order.

I went to great pains to rebalance my first RV (8A) elevators after paint. When building my first RV-10 I was confused when the supplied elevator weights where not large enough to balance the elevators, even before paint. A call to Van’s and I was provided information on “balancing for flutter” and “balancing” are two different things. In short, the guidance was to follow the instructions.

Carl
 
My RV3 is very heavy on the elevator built to plans. So, help me understand the difference between a heavy elevator and a “ not fully counterbalanced elevator” with regard to flutter.

Might be one reason that the Vne for the RV-3 is lower than the rest of the RV’s…… You’re correct, the elevator isn’t balanced really at all!
 
Before anyone gets carried away cutting open elevator horns, perhaps a call to Van’s is in order.

I went to great pains to rebalance my first RV (8A) elevators after paint. When building my first RV-10 I was confused when the supplied elevator weights where not large enough to balance the elevators, even before paint. A call to Van’s and I was provided information on “balancing for flutter” and “balancing” are two different things. In short, the guidance was to follow the instructions.

Carl

It was my understanding that with the 10, a specific elev balance weight was figured and it accounted for a painted elevator with a margin for light to heavy paint and therefore no additional work by the builder. I do not think that was the case for the earlier models, where the builder had to follow a balancing procedure.

Larry
 
Hi Robert,

The paint moves the balance aft, so a rebalance should be done. And, each elevator should be balanced individually (per Van's), not as a connected unit. The left usually needs more weight than the right. I had the shop balance after paint, and then I rebalanced it, a few weeks later - the left side needed quite a bit more weight. I did not exceed about 150ktas, until I rebalanced it.

Merrill

Plus one, I had got the same info from Vans and balanced again after paint. I had to add 5.5 oz of weight to the left one to balance it.
 
Check first

Check the balance. Since you didn't build you may not know what the balance was before paint.

I was advised that anything where the counter balance is still within the elevator is good. On my latest 7 I balanced it with counter balance slightly down (up elevator) After paint it was still down but not as much. Called it good.
 
Confused about balancing the elevator

After seeing this post, I went back to the build instructions for my 10. I dont see ANY mention of actually balancing the elevator - all I see are instructions to trim part of the lead weights and then to attach them. Nothing else.

Paul, your comment above about flutter was concerning because my elevator is not balanced, but if this was indeed the case, wouldnt van’s have us balance them?

Thanks
Charlie
 
Ok

Pretty sure we are ok. I did my elevators, as you, per vans instructions. I would say that those instructions are fine for the -10…
 
Paul, your comment above about flutter was concerning because my elevator is not balanced, but if this was indeed the case, wouldnt van’s have us balance them?

Thanks
Charlie

You figured it out Charlie - but just for anyone else that is worried, my original comments were for the OP who was talking about an RV-7. All airplanes are not alike - there are numerous elevator designs even within the Van’s line-up. The bottom line is to understand not only good practices, but what the designer specifies for YOUR aircraft.

Paul
 
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