Balancing Flaperons

[MikeRSawyer 2]

Hi folks, I'm building an Avid Model C kit that I picked up a few years ago and I've mounted a flaperon counterweight to the flaperon  just like it says in the manual, but instead of taking off some of the lead weight, I need even longer or heavier weights to balance the flaperons.  This is using the sawhorse method where the point of contact between the flaperon and level sawhorse surface  is way out by the leading edge of the flaperon.  When I set that up my flaperons don't balance with the weight hanging too low, they sit flat on the sawhorse and I'd have to add more weight to the counterweight to get the 1/4" gap on the trailing edge that is recommended.        If I hang the flaperon on the wing the flaperon hinges are too stiff to allow for balancing.   Wouldn't I need to balance the flaperon by balancing it on 2 knife edges that are on sawhorses but are directly in line with and under the flaperon spar?  If I do it that way I'm truly balancing the weight of the flaperon on it's pivot, and my guess is I'd have to remove about 1/2" of the lead weight.  Please help me out.   Thanks,   Mike

[akflyer 1427]

The counterweights supplied are fine.  They are not for completely balancing the flaperons, they are for flutter control.  Many guys originally flew without them (like the guys that did not put the wood fairings on the struts), but after an engineering evaluation by a boeing guy, it was determined that there could be flutter in certain instances.. hence the counterweights being required.  Dont loose any sleep about trying to get them perfectly balanced, just instal per manual and move on to the next step.

 

[Av8r3400 1179]

…and make sure the bearings in the turtle deck are fitted properly.  Improper fitment there is more likely to induce flutter.

[MikeRSawyer 2]

Thanks much folks.   I think the only caution I'll take is to make sure that the left flaperon and the right flaperon balance in the same way, so that they're symmetrically "balanced".