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elevator and aileron balance


kshort

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Sent my elevators and ailerons to an experienced painter (didnt have the patience or shop to do it myself). Before painting all control surfaces balanced nose down per the plans.... Well when I retrieved them from the paint shop and checked them again.....all were tail heavy. NOT GOOD... a show stopper. TOO much paint.

 

Solution Options :

 

1. try adding the .3 pounds of lead to them

but if that fails I guess my options are to:

 

2. Sand off all the paint and filler and re-apply sparingly. (paint included) $$$

3. Build all new ones (Big bummer).

 

Is my logic sound .....???

 

Please help this poor 10+ year builder.

 

KS

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KS,

Do not despair!!

 

Look at this in a methodical way:

Option 1 adds even more weight to the aircraft

Option 2 removes weight and restores desired effect

Option 3 is a lot of work, especially when you already have a perfectly good set of elevators (with the only problem being, they were painted wrong).

 

Answer: rub the paint back to the glass (or , if you are careful, the primer so as to avoid re priming) and paint again. After 10 years, whats another 2 hours of prep and paint?!!

 

Aircraft get repainted all the time. its what happens. Please dont waste your tiem re buildingthe elevators, we want to see your plane finished and flying.

 

Row

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The easiest and least expensive thing to do is add the lead - we're not talking about adding 50 lbs to the plane - just enough to safely balance the parts. Follow the plans as to how much you can add and see if that does the trick.

 

If not, then sand off the paint and try again - explaining to the painter that it is imperitive to have as light a finish as possible, and explain why.

 

Please let us know how it works out for you! I've been thinking about having my elevators, ailerons and rudders finished and painted ahead of time, just so I won't be worrying about them. :)

Phil Kriley

Cozy #1460

Chapter 13 - nose

Right wing done - working on right winglet.

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Sent my elevators and ailerons to an experienced painter (didnt have the patience or shop to do it myself). Before painting all control surfaces balanced nose down per the plans.... Well when I retrieved them from the paint shop and checked them again.....all were tail heavy. NOT GOOD... a show stopper. TOO much paint.

 

Solution Options :

 

1. try adding the .3 pounds of lead to them

but if that fails I guess my options are to:

 

2. Sand off all the paint and filler and re-apply sparingly. (paint included) $$$

3. Build all new ones (Big bummer).

 

Is my logic sound .....???

 

Please help this poor 10+ year builder.

 

KS

many builders have had this problem. first try to rebalance by taping on some weight and see if it will work. the plans state how much is acceptable. do your ailerons have the 3/8" or 7/16" steel rod as a mass balance weight. the long ez plans used 3/8" rod and the cozy IV used 7/16" rod which is .6# heavier and they are the same size aileron. elevators can have extra weight added to the inboard balance arm. you can also move the weight forward on the arm making it longer with the same weight.

Evolultion Eze RG -a two place side by side-200 Knots on 200 HP. A&P / pilot for over 30 years

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Thanks Phil and Row for the encouraging words.

 

I plan on trying the added lead and talking to the painter tonight. My gut

tells me to sand off the paint and try again. Hopefully he'll understand there's a compromise with looking good and correct balancing. My plan is to tell him to skimp on the paint on the lower surfaces and apply only 1 coat of color (white) and 2 coats of clear on the top... with me there to watch him....;o)

 

To his credit the canopy, instrument cover, nose gear access panel and engine cowls look great.

 

KS

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...all were tail heavy.

 

1. try adding the .3 pounds of lead to them

As Lynn pointed out, this is per plans and should work for the ailerons.

 

This is NOT a solution for the elevators (at least on the COZY MKIV/Aerocanard). The COZY plans explicitly state what to do if the ailerons don't balance, and how much weight can be added. The plans do NOT state that it acceptable to add weight to the elevators, and adding weight to the inboard of the elevator, while creating a static balance that looks good, does nothing to correct flutter susceptibility brought on by extra weight outboard. If it were acceptable to add weight to the elevators, it should be added outboard, not inboard (but since it's not acceptable, that's moot).

 

2. Sand off all the paint and filler and re-apply sparingly.

For the elevators, this is the right answer. The plans are clear that it's acceptable to sand off up to 1/2 of the top UNI layer on both the bottom and top of the elevators, and only stop sanding when you can start seeing the fibers of the first ply.

 

Then, fill sparingly, prime sparingly, and put ONE coat of paint on the bottom and at most two on the top.

 

If this doesn't work, rebuild the elevators correctly with drier layups.

 

You do NOT want to have elevators that are susceptible to flutter - there's a video of a VE that had canard flutter during a high speed pass at a flyin, and the occupants of the vehicle are extremely lucky that the elevators/canard didn't depart the aircraft.

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2. Sand off all the paint and filler and re-apply sparingly. (paint included) $$$

 

 

KS

Just a thought here... Try sanding the paint off the bottom only and see if that brings you in balance (plus a little). Then just add enough colour to the bottom. Only Canard builders will look under the elevator to see what you did.:rolleyes:

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On the Longeze this is a method for increasing the balance without extra weight. Fabricate a bracket and rotate the weight 90 degrees. This idea came from the CSA newsletter and has been used on a longeze for 2000 + hours.

YMMV :)

 

post-115-141090172895_thumb.jpg

Not to scale

"We choose to do these things not because they are easy, but because they are hard."

JFK

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On the Longeze this is a method for increasing the balance without extra weight. Fabricate a bracket and rotate the weight 90 degrees. This idea came from the CSA newsletter and has been used on a longeze for 2000 + hours.

And as I said, increasing weight (or moment) on the inner arm, as this is doing, does not increase flutter margin. The fact that this one particular Long-EZ hasn't had problems with it doesn't mean that the flutter margin wasn't just as low with the rotated weight as it would have been with it unrotated - it just means that the airplane never reached the limits, which were lower than the plans required.
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You don't state how tail heavy the surfaces are. Since it looks like you are going to be sanding at least the elevators, I would recommend as NeilK said and sand the paint.

 

You might be surprised how much change in balance you can make by sanding on the paint while still leaving an adequate layer. I would say sand top and bottom. You could leave a little less on the bottom surface.

 

Maybe hit it lightly with 400 and then switch to 600 until you are (hopefully) just about balanced or better yet balanced. Transition progressively to finer grit till you get to 2000. Buff the rest of the way to bring the gloss back.

 

If you're going to sand it off anyway, you might as well take it easy and go slow and see if you can remove enough to bring them into balance.

 

I'm slowly using this process with the intent of increasing the laminar flow on my Long. This takes all or most of the "orange peel" out. The shop that sprayed my Long used quite a bit of paint on most of it. Maybe they did on yours too.

Dave Adams

Long EZ N83DT

Race 83

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Hi all,

 

This thread made me worried about my long EZ elevators. They have just been paint and I didn't take into account the importance of rebalancing the elevator. This morning, I removed the right hand elevator and I weighed it: 3.9 lbs :envy: . I checked the balance: out of range:mad: :mad:

 

I removed all the paint, and now the weight is 3.46lbs, the balance is coming close to 10°..... I plan to paint again the elevator with a very thin layer.

 

One question is coming to me: in order to adjust balance, I would probably add lead, this lead should be outboard. Could you tell me if adding weigh on CS10 is a good idea? If not, where can I add lead?

 

Thank you for your help!

OT

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