Flap System Resistance?

[J Twilbeck]

I am working on Section 40 Flap System. I installed the torque tubes and UHMW Bushings and found a lot of friction and/or resistance in the system. You can push the center flap crank with one finger back and forth, but it does not rotate easily.

My question is, did others experience friction/resistance in the system? Should it rotate without any resistance?

 

[aerhed]

If you can move the center arm with one finger, you're okay. It may settle and relax a little more under loaded cycles.

 

[gasman]

On my 6A, I cleaned up the UHMW blocks after I split them. Instead of using a washer spacer, I clamped the two pieces together and opened up the bore with a spade bit. It made a good fit and a smooth rotation. I also bored the end blocks with the spade bit to make for smooth operation.

 

[9GT]

I also felt the friction was way too high on mine so I polished up the torque tube where it rides in the blocks and also opened up the holes with some fine sandpaper flap wheel. Don't over do it though.

 

[J Twilbeck]

I decided to remove the tubes and bushings from the plane and clean up the "general purpose" grease I used initially. Then reinstall the entire system using white lithium grease instead. Now it all rotates much better!

I should also note that prior to my initial post I had to sand down the holes in the bushings just to get them to slide onto the rods, but did not sand them again prior to adding the lithium grease. (that was going to be my plan B if the lithium grease didn't solve the problem)

Thanks,