Fuselage Flap Pulleys

[Steve W]

The 2 flap pulleys at station F-L on page 31 of the plans are mounted by welding a piece of 3/8" bushing stock to the nearby tubing. Is this correct and is that enough support for the pulley not to twist and deform with all the load experienced deploying the flaps? Is there more of a support not shown on the plans that others are constructing? Anyone have any pictures? Another question is how far does the flap torque tube extent out from the double root rib? Using the hole for the rear spar attach flange as a reference, where would the flap arm be in relation to this? Thanks

Steve
P203

[Collin Campbell]

Here's a couple of pictures of what I did on the Patrol fuselage flap pulley. Added a small diameter tube 1/4" .035? best I can remember.

DSC00007.JPGDSC00008.JPG

[Collin Campbell]

On the flap arm at the wing root question, others have recomended establishing this after the wings are hung. But I have had good success on both the Patrol and the 4-place by extending the flap torque tube so the flap arm centers on the rear spar attach hole. There is the greatest amount of clearance at that point, although things do get a lttle tight with the flap cable attach to the arm. I used a swaged fitting at this location as they are a bit more "compact" than a cable shackle. Don't have a picture of this, sorry

[Steve W]

Thanks Collin for the photos and reply. I'll strengthen up the assembly for some peace of mind. I don't have the flap arms welded on the end of the torque tubes because I couldn't determine the distance from the plans. I left it along with the upper pulleys until I put the wings on for a good alignment and fit. I thought I left enough length on the tubes but I see that it will just come out to align the arm with the spar center hole on the fitting. Trying to get the last of the welding done so I can paint the fuse before work starts the summer. Thanks again.

Steve

[jaredyates]

I'd be very cautious of strengthening things for peace of mind. It's your choice as with any homebuilt, but there can often be unintended consequences of doing things like that. Maybe you could give Bob a call and hear his thoughts about drawing it that way?

[Collin Campbell]

Jarad, yes, good advice. I did talk to Bob about what I was going to do. He didn't think there was much of a load on the flap cable pulleys, but said I could try that if I wanted, it wouldn't hurt anything.

Collin

[Bcone1381]

Collin, I have been meaning to send out some photos for a few days now. I hope these help.

Each photo below a small tube that is used to attach a Flap Pulley at satiation F-L from a factory Patrol fuselage.

The first photo is for the Flap first pulley. The attachment is encountered by the flap cable as it runs back towards the tail after leaving the flap handle and arrives at station F-L for the turn to the center of the fuselage.

The second photo is the pulley attach point in the lower part of the middle of station F-L just above idler arm that connects the elevator push pull tubes. just above this pulley is where the Flap Junction Plate splits the flap cable into a cable for the Right Flap, and one for the Left Flap.

The third photo the pulley attach point for the left flap cable as it arrives from the junction plate and turns forward towards the inboard flap lever/flap torque tube.
IMG_0009.jpgIMG_0011.jpgIMG_0010.jpg

[Steve W]

The only one that really gets my attention is the middle one that is attached to the 1/2" .035 tubing. It will bend with the load. If that's good enough for the factory then I'll just carry on. Thank so much for the photos.

Steve
P203

[Chewie]

Bcone1381 or anyone who has easy access to the pulleys described above: can you please let me know what OD or spec these pulleys are? I gather from the July 2021 engineering change that the bushings are .25 ID. And Patrol sheet 31 shows them about 2.5 OD but with a 1:10 scaling I'm not sure I trust that.

And actually, same question about the pulleys at the bottom of the strut on p. 27. An old bear track said these are 2-in OD, so I assume bore is 1/4 because that's all I can find.

The other pulleys are pretty well spelled out.

Much appreciated!

[spinningwrench]

There is an engineering revision from Bob indicating the need to strength the first flap pulley weldment. Look that up in Engineering Changes on this forum.

Here is a link to my builders log, look under "Flap System" and you can see my solution to strengthen this weldment.


https://eaabuilderslog.org/?blprojad...7Xgxhu5Dt&sid=

[Bcone1381]

Mark Goldbergs hardware document that I recieved up to 5 years ago calls out an MS24566-3B pulley for the six flap pulleys and the pulley at the bottom of each wing strut. It's exactly what I used.

My Genuine Aircraft Hardware Reference Book this pulley has a
-2.00."outside diameter,
-1.510" groove diameter,
-is used for cable diameter 1/8 thru 3/16" diameter.
-Hole diameter is .2500.
-600 lb load limit.
-Bearing number is KP4K. But the bearing cannot be replaced.

[Chewie]

Perfect, thank you Brooks!