Elevator Counterweight.

[ncarmon]

Ok, I've read everything I can in all the old threads about elevator counterweights. The information is really confusing and "ThreadJack" is rampant.

I get that I'm not supposed to cut the left elevator Lead "down to size." It is only on the right elevator (per plans).

Do I cut the right elevator lead down (the 1/2 inch per plans) before putting the tip on? For those that didn't cut it down, how did you adjust the counterweight after painting? I don't think it makes sense to drill from the inside, seems that it would make it less secure.

Let me know thoughts!

Thanks....

 

[DGlaeser]

Balancing act . . .

My experience, as well as my son's, (both 7A's) was that installing the lead per plans produces elevators balanced just fine after painting without any adjustments. My thoughts are: cut the right side per the plans, install both weights and tips and don't worry about it.

 

[robertahegy]

Dennis is right on. The left side balanced perfectly for me, leaving the weight whole. I carved the right side pretty close to plans and just drilled a little out to bring it into balance. I don't think that small amount of imbalance will matter. Here is a shot of how I drilled the right side out. I molded the tips right into the weights on the outboard edge. Some superfil or epoxy flox works nicely.

Roberta

 

[Captain Avgas]

Obtaining precision balance

I'll tell you how to get a PERFECT balance on both your elevators. Initially....don't remove ANY mass from your lead weights when fabricating the elevators.

When you're fabricating the counterbalance arms of the elevators instal a 3/16" platenut on the arm at the existing tooling hole (platenut will be inside fibreglass tip) and use countersunk rivets to secure the platenut. See the photo.

When you have the horizontal stabiliser finally installed on the fuselage then temporarily mount the elevators and check them individually for balance. Have the elevator fibreglass tips on temporarily to allow for their mass as well. Then file mass off the lead weight (from the side where it would be inside the fibreglass tip and won't be seen) until each elevator is neutrally balanced. After that you can instal the fibreglass tips permanently.

If you find after you've painted the elevators that they're hanging down because of the additional paint mass then instal one or two (or more) large washers with an AN3 bolt at the platenut you installed (and lock wire it) to regain balance.

Bingo....you'll have precision balance.

Left click on photo for larger size.