Dan:
I really would like your views on just how much I'm giving up by not having the horns centered in the (insert noun here -- cross-bar? tie rod? thingy?). I get the fact that you feel that there'll be a difference in stiffness from the bellcrank to each flap -- but, how much difference do you see in practice? And if I do go to fix that, are you suggesting a monstrously wide tie bar that goes into the flaps (and elevator) off center?
The span of 3/32" wire joiner on
W500 is about 2 1/4 inches as is span of joiner on elevator. Narrower parts would probably have been preferred but with them being fabricated by Derek in the Santa Barbara area, me in the NW, we both allowed for some leeway with these parts. If these pieces were viewed as "monstrous" they would not have been used.
Also of note is that flap and elevator horns bushed both left and right of upright. Right bushings centered in fuselage, left units hanging out in the breeze.
As to your central question: I do not know how much difference left and right is seen in practice.
But that's the whole point: Not seeing any difference at all, no possibility of same in a rather critical part of control system.
Instead, let's look at what nearly all of us do know.
We know forces on CL Stunt control systems quite a lot higher than would seem to be the case (thanks again, Ted, for pointing this out so many years ago!) from merely looking at a fairly lightly-loaded, relatively small, certainly slow-flying model aircraft.
If this were not the case all of us would happily be fitting Du-Bro Kwik-links to our linkage when this is known to be the Kiss of Death for any CL Stunt model. Note that larger, heavier, faster RC ARFs get away with even cheesy D-B knock-offs with acceptable reliability.
We know that based upon what works in an RC Pattern model our use of 1/8-inch joiners for flap horns seems silly. I envision an accomplished Pattern flier (not you-know-who, maybe someone like Chip Hyde) being taken on a tour of an
Impact, something I have actually done. Universal reaction to such hardware is one of disbelief.
We know that "tweaking" flap horns to get our wings level to the lines is a simple matter of using nothing more than finger pressure to net rather big changes, meaning mild pressure gets the job done. I think this is what one could call a clue...
We know that joiner material from coat hanger wire won't work. Not stiff enough.
We know that if we mock-up a flap horn installation that is fitted with two vertical pieces, one centered and one off to the left end, force applied to the centered vertical will certainly result in equal forces (or very nearly so remembering joiner has been heated during assembly) applied to each end of joiner. In our case that portion of the joiner which drives the flaps. Can't say the same thing when applying force to vertical on the left; there simply must be a difference from one end to the other of what is essentially a torsion bar.
Ah, but how much? We don't care to know, nor ought there to be much value in knowing, because...
We do know that with the vertical centered on flap and elevator joiners the best shot at equal flap/elevator movement has been incorporated into the linkage.
And so when out at the field, trying to bitch-slap the thing into trim, seeing a wee bit of roll in maneuvers, the
last thing which potentially needs addressing--and is also one of the most difficult to fix--is differential drive to movable control surfaces.
So proceed as you see best, but with existing horns in need of proper bushings anyway the choice is fairly obvious from here.
Dan