I am starting a 60 size Legacy and noticed the bellcrank lever was turned to the inside. (between the leadouts) what difference does this make not pointing to the outside wing?

I wondered about that myself as I tried turning the bellcrank leadout to the inside on a Shark and there doesnt seem to be very much space between the pushrod and leadout what do others do put extra washers between the ball link where it attaches to the bellcrank to make sure there is good clearance?
 Richard Edwards

I confess I have never understood this solution.  Why not just run the pushrod out the bottom, and put the flap horn on the under side?  It would accomplish the same thing (front leadout "up") while avoiding the interference problem with a reversed BC.  More than one way to skin a cat.

--Ray

I think clearence to the bottom of the fuse would be the problem there. Not on all models, for sure. But a lot of the classic stunters don't have a lot of space between the bottom of the wing at the trailing edge and the fuse bottom.

I am positive you could easily do that with a profile, but the problems Clint stated are very real with most built up fuselage stunters.

The central problem with an underslung flap horn is not the interference with the fuse bottom or pipe tunnel.  The real loss is that the increased angularity of the pushrods re the horn axis.  In order to get the movable surface to swing equally in both directions, the pushrod has to make a 90 deg intersection with the centerline of the horn leg.  Many aileron hookups on R/C stuff use this angularity error to make the aileron swing more up than down, to equalize the effective control given the lower pressure on top of the wing.  This is especially true for airplanes with the stab mounted above the wing centerline, as most are.  See Al Rabe's writings for discussion of the control errors caused by pushrod angularity.  If the underslung layout is used for other reasons, then my guess is that a custom flap horn with the upright aft of the trailing edge would have to be fabricated.  Tom H.

Good reasons have been given for why the underslung, (bottom) flap horn is harder to work with. The least of which is related to the flap and which line is the up line. There becomes a real and difficult geometry solution to having the elevator horn now on the top of the elevator. If the stab is moved to a point below the wing centerline, then the problem is non existant, but, now the stab is blanketed in level flight.

I think too much is being made of the possible problem. I've been using the reversed bellcrank for years, and not had an interference problem with the leadouts. The angle that the pushrod has is sufficient to clear the leadouts, esp. if you use a ball link at the bellcrank.

There are several solutions for this, a problem that isn't really a problem, but you run the risk of over complicating the control system. 

I am like someone else said here.  My experiences with flipping the BC to where the front line is up has not lead to any issues with obstructions. (?? ?? ?? ?)