Electric flap weldement “play”

[nohoflyer]

I’m installing the weldement which moves the flaps. I’ve secured them on the sides into the plastic, notched pivot blocks. The blocks screws have been tightened to the bulkhead.

My question is how easy should this thing move up and down? Because now it takes a few pounds of pressure to rotate it. What would be the solution? Widening the holes in the pivot blocks? Or is this normal?

[wirejock]

Originally Posted by nohoflyer

I’m installing the weldement which moves the flaps. I’ve secured them on the sides into the plastic, notched pivot blocks. The blocks screws have been tightened to the bulkhead.

My question is how easy should this thing move up and down? Because now it takes a few pounds of pressure to rotate it. What would be the solution? Widening the holes in the pivot blocks? Or is this normal?

I found it very tight as well. Curious what others have done.
The rudder weldment was also really snug so I used a drilled bolts and castleated nuts to get the tension perfect then pinned with cotter pins. I can always adjust them tighter.

[agent4573]

Misread this at first... Have you put the center block in yet or just the ends?

[Tommy123]

Get it completely assembled before modifying anything.

[nohoflyer]

Originally Posted by agent4573

Misread this at first... Have you put the center block in yet or just the ends?

Right now just the ends. Although it seems that right now the weldement is under less friction than if another block is added to the equation

[lr172]

same here. A bit of work with sandpaper on your finger will relax the bore a bit for freer movement.

[bjdecker]

Instead of trying to "open the bore" of the UHMW blocks, I used a piece of fine emery cloth and "red" 3M scotchbrite pads to polish the ends and middle section of the flap torque tube (aka weldment).

From there I beveled the ends of the tube with a 45° chamfer, debured, and worked over with some 400grit wet/dry to smooth the tube ends.

I applied a light coat of Lithium wheel grease (white, water proof) to the polished sections of the tube. Place two AN960-10 washers in between the center bearing block halves (F-680) -- this makes up for the material removed when you slice the block in half. Torque all AN3 bolts to spec (~25inLbs).

The torque tube should hold its position without drifting down, but be easy enough to move by hand without any "grunt."

--- As an aside, I upgraded the flap push rods (F-759A) to the hex version from the RV-9 (VA-256) --- I know, I know, it won't work...

[HFS]

You might also consider checking the side-to-side alignment of the supporting longerons. If the flanges to which the UHMW blocks are attached are not in good "alignment", the blocks will "tip" just enough to make the drag you are talking a about when they are tightened down. Also, you might check the fore and aft alignment of the blocks in their mounting holes in the longerons - if the blocks are not parallel when bolted down, you will create drag as well.

My Rocket, required such "shimming".

YMMV - But it is worth considering.

HFS

[PilotjohnS]

I did not need to do anything to my blocks, but I did have to remove some of the powder coat (paint) from the rod to get it free.

I would make sure the blocks are running on the steel flap shaft without any powder coat interference.

[nohoflyer]

Originally Posted by HFS

You might also consider checking the side-to-side alignment of the supporting longerons. If the flanges to which the UHMW blocks are attached are not in good "alignment", the blocks will "tip" just enough to make the drag you are talking a about when they are tightened down. Also, you might check the fore and aft alignment of the blocks in their mounting holes in the longerons - if the blocks are not parallel when bolted down, you will create drag as well.

My Rocket, required such "shimming".

YMMV - But it is worth considering.

HFS

The blocks are bolted to a bulkhead not the longerons.