RV-3 Elevator Horns

I?m about to finish my RV-3 empennage. At the moment fitting the elevator horns. Having ground them to fit inside the flanges of the spar and the root-rib, it?s time to powdercoat, before riveting them to the elevator skeleton. There is this hint in the 27 Years of Rvator (6/95 p.67, Modifying the RV-3 elevator horn) saying:

" The pushrod arm of the weldment may hit the rear fuselage bulkhead before full up-travel is achieved. The arm may be modified as shown"
There is this drawing, not showing any dimensions, so I guess the portion to grind may vary from builder to builder.

My question is, should I grind the pushrod arm of the WD-405 now, so the cut also will be powdercoated or, not knowing yet if the arm will touch the rear fuselage bulkhead at all, I wait for the final assembly, grinding later, priming and painting it with the spraygun?
Similar question for the holes that attach the elevators to the central bearing HS-309 and the holes for attaching the rod end bearing of the main pushrod.
Should I drill now or later, when mounting the empennage?

Thanks for any recommendations from the experienced RV-3 Slowbuilders

Peter

You don't HAVE to powder coat them. Many people simply prime them and paint them with the rest of the emp.

My recommendation is to get the tail fitted to the fuselage.. Then prime and paint all of it together. You may find that the HS skin needs to be trimmed because the travel is more than you thought on the bench. Little things really pop up on the none prepunched kits.

I would put a good primer on the horns before riveting them to the elevator spars.

You can go ahead and drill the center bearing hole on the horns after it's riveted on. Same for the pushrod bolt hole.

Mine are riveted to the elevators. I had to trim them a bit for that and used SEM primer or zinc chromate there, I forgot which.

I haven't made any accommodation for the fuselage yet since I haven't gotten that far. I figure that when I have a fuselage and know what's necessary, I'll deal with it then.

But I did assemble both elevators to the stabilizer and make that hole for the center hinge. With that in place, I was able to check travel and verified that I could actually reduce the hinge distance from the elevator web just a hair and still have clearance.

Dave
Now on fuel tanks.

Elev Horn Mods

I have pics of some clearance accommodations I made. Other folks confirmed the need at the time. I can send by email if you want them.

Wd-405 Elevator Horns, different angle in RV-3 plans

Thank you guys for the advice. I will test my new primer for the elevator horns. Until now I used a waterbased quite healthy stuff. it's fine for the inner surfaces, but gets easily scratched on parts like the hinge brackets and elevator horns. The new one is the 2 component epoxy type.

There was a another surprise when I laid the skeleton of the left elevator on the skin with the dimensions marked according to drawing sk-6.
It seems that the WD-405 has another angle than the angle on which SK-6 is based on. In fact, the plans (DR28 left,below) show 70?, the WD-405 is 67?, that means the tip of the root rib moves towards outboard, with the consequence that also the E-310 must be moved, it's flange gets out of the range of the rivet which normaly would fix it to the E-302 spar and the hole in the WD-405 spar side does not fit anymore to make the trim cable pass through the spar.
Though, never having read anything about this, I'm not sure if I did something wrong, but I don't think so. One thing is for sure, I dont't want to bend or modify the weldments

So my idea is to modify the E-310 in that way, that it remains in the position (5 3/4 from the next stiffener), that it get's caught by the WD-405 rivet and it remains in front of the hole, through which the trim cable passes. But it means also, that the cutout for the trim cable in the bottom of the E-310 must be moved a little bit towards the tip.
Did anybody else experience that problem? How did you resolve it?

I hope I could explain it, that anybody understands.

Peter