RV-3 Elevator horn interference

The control horn on my 2010 vintage empennage kit hits the horizontal stabilizer spar flange before reaching 20/25 degree down deflection. Even with the center bearing bracket bolt head removed, it is still short of specified 20/25 degree deflection.
The steel horn stamping is different than the 2008 vintage part on on the salvage plane I am rebuilding.The new horn is much wider than the the drawing shown in the plans set. I assume it is a universal part to be used on multiple RV's. This is not a crisis. I am just seeking the benefit of other's experience before solving the problem.

We notched the spar flange Larry - this is the way it is shown on the RV-8 plans, and the structure is essentially the same, so I used my engineering judgment and notched the flange.

Paul

Ditto Paul's approach also.

How about a photo?

Got to admit that the idea of "notching" a spar flange is not one that would come to mind as a solution. Perhaps I'd call it relieving it locally instead. Photo, please?

Thanks!
Dave

I`m having the same problem Larry, even with the rear spar notched the weldment hits the lower bolt heads. I will probably sub these with C/S head AN3 instead of cutting and rewelding unless anyone else has a better fix.
Regards Peter Pendergast

RV3 elevator horn

Peter,

I notched the steel horn to give the bolt head AND the pivot bearing carrier ( aluminum angle ) some clearance. The material removed leaves the control horn with more size the than the little drawing ( assume original RV3) on page 28, detail Wd-311.

Then I replaced the steel flange that was removed from the control horn with .062" 4130 strip. I can send pics to your e-mail.

The problem arises from maintaining the 3/4" distance from the Heim joint centerline to the face of the spar as specified in the plans. This is consistent with the rudder spec. I have observed others just screw the Heim joint out of the spar further, but this requires that the pivot bearing bolt hole be drilled more than 13/16" from the center of the tube as well. This is probably not a big deal to the airplane, but you need to plan for it before drilling the pivot bearing hole.

Larry

Larry, I agree with everything you observe, having said that I increased the inboard spar to spar distance just enough so that when I drilled the hole in the horns for the centre bearing the flat on the bolt is tight on the tube of the weldment which is larger dia than the drawing and used a metal lock nut (smaller O/D than standard nylock) My observation of using C/S on the bottom bolts is the C/S only goes half way through the 1/8 angle so still plenty material left in the hole.

Peter