Flap Pulleys

[noema]

I have spend the last week making the flap pulley guards and temporarily installed the fuselage part of the flap control system yesterday. The guards were more work than I anticipated. It took me many test pieces to get the tolerances around the pulley right. I also integrated the pulley 1 brace with the pulley guard.



Things turned out fine for the most part. I have two pulleys which seem to have a bit of an alignment issue with the cable direction. What's a good way to adjust this?

Pulley 3R towards the front seems to be tilted a bit too much inward:



Similar for pulley 4L:

 

[robcaldwell]

I did not need pulley guards for the inside upper flap pulleys. Those sit almost flush against the top tube and keeps the cable from jumping out, which is what I think Bob intended.

 

[N942VT]

The cable runs in the upper pulley area you show can handle a good bit of misalignment, there is not constant movement there. The forward pulley run can't accurately be determined without the flap tube in place. The flap tube can be adjusted in or out some to accommodate the cable run.
If you feel the need to adjust the the pulley angle you can file the tube end to the proper angle and then put a slight bend in the pulley bolt. I did this on one that I welded the the pulley mounts on and the angle was off too much to leave it. Difficult to get it right but that's your only option. With what you show I don't think you will have a problem as is.

 

[noema]

Thanks. This makes sense.

 

[noema]

I agree. The top guard of pulley 3L does not add much. I made it before I realized the fuselage proximity does the guarding.

 

[Bcone1381]

The pulley can also be adjusted outward a little bit by adding washers under it, or I suppose inward by removing some material from the pulley mount tube.

But when you drill the flap arms, you also set the location of the inboard flap arm. The arm needs to be set so the flap cable and its attach hardware is not contacting the airframe... specifically the wing spar plates, or the attach fittings. If one focuses on the direction that the cable exits the last pulley, and not on the relation of the cable to these points, it might be frustrating.

 

[noema]

Fixed it, thanks for the suggestions. Just moving it axially did not work. I had to angle the pulley axle slightly. I angled the mount tube end with a file and bent the bold slightly. The bend in the bold was small enough that I could still push it through the mounting tube with some grease and light hammering.



The other misalignment on pulley 4L is quite minor after holding the other end of the robe out where the final cable would attach to the torque tube lever. Will see how it looks with the cable installed.