Elevator Balance Weight Calculation

[Airplane3472]

Hello,

I am building a QB Bearhawk in Texas (Sherman - north of Dallas about 60 miles). Fuselage is QB #99. I am at the point of adding lead to the elevator. I understand the process and see no problems accomplishing the task. Only question is, how much? I have read and re-read the sections about calculating the exact weight based upon estimated fabric and paint weight. However, it seems like there should be a number (pounds) that can be used which would accomplish the counter balance requirement. I was planning using 2.2 pounds per elevator tip. Would that number accomplish the task? I don't want to purchase actual fabric until I am completely pre-assembled and ready for cover and determining the actual square footage of fabric based upon the curve of the elevator is higher math that I took in college.... LOL. From other posts, it looks like actual weight is not absolutely critical as long is the counterbalance weight is close. Any ideas?

The forum is a great tool and as a builder, I appreciate eveyone taking time to answer questions and share ideas. It really helps those of us that are "Assemblers", not "Engineers". I can put anything together, just can't design it worth a flip...

Thanks,

[Gavin Chester]

Check out Eric's site for the info you need.
Add a little more than you need and drill holes through it or shorten it, to get it right , remove material starting from hinge side and work towards the tip.
If you weight is permanent apply some form of anti corrosion.( dip in thinned epoxy primer ) after you are done.

[Mark Goldberg]

Brent, what a lot of guys do actually balance their elevators and not just use an amount of lead from someone else's build. Granted, they should be very close. You just have to balance them by putting on the weight allotted to the fabric (which is not on yet), and start adding lead in the area where the lead goes until it is balanced. Then melt and pour the lead. Mark

[Enewton57]

I went with the amount of lead shown on the drawings and then had to remove a large portion of it to balance it. I recommend doing it the way Mark outlines above.