OK, so it's best to balance the stab on a model?
I'm finishing up a Trim F-86, it takes a whole lot of lead to balance the full flying stab.
If I just get it close, will it make it less likely to flutter?
Not sure I can get enough fishing sinkers in there to fully balance it.
I'm using an 8411 but it's on the other end of fairly long CF push rod that seems very stiff. Maybe I should support it in the middle.
This will be powered with a 17 lb turbine.
I assume this plane will be fast enough to get flutter problems.

Hi,

Does Trim have any input in their instructions regarding trying to balance that stab on the pivot? I'd take a look at that before taking action based on the "information" in this thread.....

Good luck!

Pete,

I plan to balance the stab on my Trim F-86 as well. Here is a pointer for you....Buy the lead sinkers that will be oversize for your application. Make the cutouts for the weights in the stabs a triangular shape that follows the leading and inside root edges of the stabs. You can remove the foam from the inside of the stabs up to the leading edge and out to the inside of the skins. Next, using a hammer and hard surface, (anvil on a vice or the concrete floor) beat the lead weight to the shape you desire. (the triangular shape that matches your cutout in the stabs) This will be easy as the lead is very soft. Assemble the stabs on the plane. Place these weights on the top of the stabs on the leading edges in the areas you cut out. Balance as required. If you have too much weight you can snip off pieces of the lead with heavy duty side cutters. Try to get both sides equal in weight. I shoot for the trailing edge of the stabs to droop just a degree or two. This will compensate for the weight of the epoxy when you glue the weights in. Additionally, I try to always balace AFTER the stabs have been finished as the weight of the finishing materials and glass cloth will affect the final balance. By making the lead weights this custom shape you will be able to put the weight as far forward as possible....Exactly where it is needed!

Take the stabs apart and glue in the weights with epoxy. Re-assemble the stabs and note how they balance. If you've taken your time you should be right on the money. If the stabs hang slightly nose down you can drill out the lead weights a little at a time until you're satisfied.

I hope this helps...Kevin

PS---I'm thinking about putting a dowel inside of the hollow CF stab pushrod to make it a little stiffer. I, too, will be using an 8411 for stab control.

Shaun, nothing said in the instructions about balancing the stabs.

Kevin, good suggestion. Due to the taper of the leading edge, the weights get further back as I stuff them in. Your suggestion would put them further forward.
I've got about 3 oz's in each one now and they're only close to balancing. If I can get them further forward it would help.

I was wondering if as you get closer you raise the flutter frequency? There s/b a safe point if only we new what it was.

I have mine primed, will shoot the color as soon as it warms up a bit.

Thanks for the ideas, will let you know how it works out.