A

alpinelakespilot2000

Well Known Member
I started drilling my inboard counterweight to balance my RV-9 right elevator. I've got about 7-8 holes that are 1/4" in diameter and go about 2/3-3/4 through the thickness of the weight. As the picture shows, however, it's done very little to balance the elevator.

Before I get too much farther along, should I be expecting to have to take a lot more out? I'm a bit concerned that I'll end up with swiss cheese on this weight before things balance. FWIW, the outboard (inaccessible) weights were trimmed to plans. It looks like those should have been a lot smaller, but that ship has sailed.

Thanks for any confirmation, one way or the other.

 
On my 6, I drilled a bunch out like that. After painting, I had to put it all back....with pins and molten lead. Fiberglassed over (with just resin), to make it look good. Everything is interlocked with the pins.

L.Adamson
 
Careful here, from what I've heard painting the elevator will cause you to need MORE lead to balance. If you remove enough now to make balance perfect, you'll have too little lead once the paint goes on.

Assuming you plan to paint someday, of course.
 
I did remove more, and I sort of wish I hadn't. Paint will affect the balance. Having both elevators tied together along with the rest of the elevator control system will also affect balance.

Once you have the system hooked up, if the elevators stay where you put them then that's probably about right.

It would be nice if we had some more precise guidance about this subject, but maybe one way to interpret the lack of guidance is that it isn't that critical.
 
Thanks. I plan on leaving them a little nose heavy for future paint, but I'll continue to take a bit more out. From my review of previous threads, it appears that many who balanced before and after paint found that paint actually did relatively little, at least compared to what they expected, so I think I'm going to aim for about 1" nose down without paint. Good compromise? Anyone see any big issues with this?
 
Too Light

I removed too much lead on the side with the electric trim. I am now trying to figure out how to add some weight back to that side. I have already glassed in the outside.
 
I don't know if this helps -9 builders, and in any case it's too late if the elevator tip is riveted on, but on the -7 counterbalance rib there's a tooling hole just aft of the lead counterweight (which looks a lot like the -9 counterweight, at least mine does). If you surround the tooling hole with a K1000-3 nutplate (on outside of rib) then later you can add weight back on the inboard side by using an AN-3 bolt with washers, a small piece of lead, spent uranium, etc.

Not my idea. It's documented in other threads here.
 
Counter weight reply

Lots of good suggestions posted here. What I can share is what I did on my 9A. First balance each elevator alone without being connected together. Drill more holes on the side not covered with the fairing. You will need to refill those holes with molten lead. Also do not drill so deep that you drill a hole through the bottom of the lead counter weight. Makes it difficult to refill the hole. I would suggest that each elevator should be balanced with or without paint. After plane is painted you will refill the holes with lead. Any open holes after balancing can be filled with feather fill or equivalent. (minor weight increase). If after all holes are filled and the elevator is still needing more weight, a piece of lead strip can be added to the rear of the lead counter weight. I secured mine with JB Weld and 2 screws. This worked for me. Good luck. There are quite a few good suggestions to choose from.
 
Remove a bit more lead than needed

then apply a rivet nut to the rib spaced about 3/4" back from the lead weight and extra lead can be added as needed to bring the surface back to balance using just a bolt and some Locktite 243. When I realized I'd removed to much weight to balance after I paint I added rivet nuts to the rib on each elevator. A lot less hassle than using lead dowels and allows for easy fine tuning. It allows you to remove your original lead with a fair amount of impunity and recover from it later.
 
For others who will confront this issue down the track. Consider attaching the elevator tip with screws and nutplates rather than rivets/glass and you will be able to get access to the lead weights after painting.

Fin
9A
 
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