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-   -   Elevator Balance? (https://vansairforce.net/community/showthread.php?t=169882)

mturnerb 03-22-2019 07:11 PM

Elevator Balance?
 
I can't find any guidance in the plans about elevator balance. I've seen conflicting information in the forums (surprise surprise).

Just wondering how other -14A builders have approached this. I've installed the counterbalance weights per plans but don't know if I need to otherwise balance the elevators and/or whether to do each individually or as a unit. I'll be flying soon, but paint will wait until after initial flight test phase.

Bavafa 03-22-2019 08:57 PM

Quote:

Originally Posted by mturnerb (Post 1333690)
I can't find any guidance in the plans about elevator balance. I've seen conflicting information in the forums (surprise surprise).

Just wondering how other -14A builders have approached this. I've installed the counterbalance weights per plans but don't know if I need to otherwise balance the elevators and/or whether to do each individually or as a unit. I'll be flying soon, but paint will wait until after initial flight test phase.

I balanced mine individually which is per advise/instruction that I had got from VANs and also based on pervious experience on my 7A which was also based on advise from vans.

This is exciting time so my congrats .

MED 03-23-2019 05:16 AM

The 14 plans don’t call for it, so I have not, yet. You might/would need to balance again after paint.

jeffw@sc47 03-23-2019 06:47 AM

Van's - tell me what I need to do.
 
Quote:

Originally Posted by Bavafa (Post 1333715)
I balanced mine individually which is per advice/instruction that I had got from VANs . . .

If Van's has advice for balancing control surfaces why don't they make that available for 14 builders; maybe they do but it is tucked away so you have to ask or search for it.

Curious minds sure would like to know more about this.

Nova RV 03-23-2019 07:14 AM

If they want them balanced individually, it definitely does not mention it in the plans (9-26). The weights are all the same. The individual elevators are not the same weight since one has the trim servo and tab and the other does not. Balancing them to the same neutral point individually makes sense on one hand but the elevators are bolted together and work as a system so balancing them together is the way they function. Neutral balancing one at a time would seem to benefit only if the halves would separate at the pushrod and if that happened, you have many other issues than to worry about balance of each half. FWIW I balanced mine together and have never had any issues.

mturnerb 03-23-2019 07:31 AM

Thanks for all the replies. Advice from my tech counselor is to build on.

Bavafa 03-23-2019 09:30 AM

On important issues such as this which could potentially be the source/cause of a flutter, why not go to the mothership for advise. The phone call is free and the advise, one would think, more scientific.

Anyhow, that is my 2 cents,
Balancing the elevator might have done something for me, might have not. But for sure it gives me a bit more of peace of mind.

Carl Froehlich 03-23-2019 09:40 AM

Yep - call Van?s.

On the RV-8A I went to great pains to balance the elevators, taking weight off before paint then adding it back on after paint (big mistake). On the RV-10 I was surprised the elevator weights were way short of achieving balance, even before paint. Van?s told me that is by design. Counterbalanced for flutter protection does not necessarily translate to perfectly balanced.

For the new RV-8 I just bolted the weights on per plan and built on.

Carl

squarebush 03-31-2020 08:47 PM

I had contacted Vans this week and they were here nor there on balancing the elevator short of maybe balancing them individually slightly forward but keeping in mind they are bolted together.

While working on my elevator fairings this week and the horizontal laying flat on a table, I noticed the right elevator was 6 oz heavier forward than the left when using a digital scale. Left side with tab was almost neutral give or take an ounce. I had to put about 5 oz on the trailing edge to to get them even. Any one else experience this or build on? Taking out the trim actuator made little difference. Maybe I shaved one lead weight down more than the other. Perhaps nut plates on these fairings are smart for the future..... Thoughts.

Bavafa 03-31-2020 09:15 PM

Quote:

Originally Posted by squarebush (Post 1418607)
I had contacted Vans this week and they were here nor there on balancing the elevator short of maybe balancing them individually slightly forward but keeping in mind they are bolted together.

While working on my elevator fairings this week and the horizontal laying flat on a table, I noticed the right elevator was 6 oz heavier forward than the left when using a digital scale. Left side with tab was almost neutral give or take an ounce. I had to put about 5 oz on the trailing edge to to get them even. Any one else experience this or build on? Taking out the trim actuator made little difference. Maybe I shaved one lead weight down more than the other. Perhaps nut plates on these fairings are smart for the future..... Thoughts.

Todd,
Your left elevator will require more weight than the right due to the trim tab. Prior to paint, mine were fairly balanced for the left and light on the trailing edge of right side. After the paint, I added 5.5 oz of weight to my left elevator and none to the right which were checked each of them balanced individually and then bolted together.

Hope this helps.


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