Trim Cable Pulleys

gusc · Post by **gusc** » Tue Nov 04, 2008 20:46

Where are the first trim cable pulleys aft located?

I started to install a shoulder harness on my rear spar carry-through and found these pulleys blocking the channel steel harness mount which is supposed to slip over the square carry-through and bolt to the wood former.

The not-to-scale drawing in the manual makes the pulleys appear to be pretty far aft, much aft of the rear spar.

Dennis,

Is your fuselage still open enough to see where these pulleys belong? The headliner sure makes this a pain.

marklamon · Post by **marklamon** » Tue Nov 04, 2008 20:57

The trim cable at the rear spar should run thru a phenolic or nylon block. Someone may have added pulleys there instead. Mark

gusc · Post by **gusc** » Tue Nov 04, 2008 21:09

Mark,

Pg 15 of the Champ manual shows a set of 1-2393 pulleys about two thirds of the distance from the trim lever to the rear pulleys. It doesn't show any blocks?

Dennis · Post by **Dennis** » Tue Nov 04, 2008 22:31

Sorry Gus, it is closed up. Are you talking about the rear pulleys for the ailerons? That's about the location at the side of the fuselage.

Dennis

Mikek · Post by **Mikek** » Wed Nov 05, 2008 08:49

gusc wrote:Mark,

Pg 15 of the Champ manual shows a set of 1-2393 pulleys about two thirds of the distance from the trim lever to the rear pulleys. It doesn't show any blocks?

[img][img]http://i11.photobucket.com/albums/a172/ ... trim17.jpg[/img]

The 7AC service manual shows Two (2) fiber blocks one just behind the front seat another one over the back seat.

The picture if it somes thru shows that one of my blocks was replaced by a aluim strip that lets the trim cables not cut into the wood. The manual also shows the pulley 2/3 of the way back.

Mike who will be driving a car while in AR. [/img]

james gevay · Post by **james gevay** » Wed Nov 05, 2008 14:23

Gus, there should be some wear strips over the top of number 3 and 4 overhead formers over the cabin. Mine had some hard plastic like you see on kitchen counter tops. It's there so the cable doesn't wear through the wood. You don't want any material that could wear through your cables either.

This picture shows it from the top.

The 3rd picture shows the first 2 pulleys, their near the top of the diagonal tubes, between the large fuselage formers number 2 and 3, or just above and to the right of the yellow and white minnow bucket in the background.
The other 2 pulleys are just under the stabilizer spar, and the last 2 are on the elevator.

gusc · Post by **gusc** » Wed Nov 05, 2008 19:02

Thanks guys, this clears up the whole thing. James, those photos are great.

It is now obvious what the problem is, the cables are completely misrouted.

I'm trying to install the same STC shoulder harness shown in "Mike who will be driving a car to AR's" photo. The problem is that my cables are routed UNDERNEATH the formers and spar carry-through and the pulleys are at the bottom!! This is not the first crazy thing I have found in this airplane. I'm convinced the guy who rebuilt it should take up another line of work! I don't know if I will ever be able to straighten out this mess with a headliner in my way.

I now see the fiber blocks on Pg 12 but they aren't labeled. It is no wonder I didn't see them because I was looking for them at the bottom!

James,

I'm not sure if I see the pulley. Is it the white object just in front of the diagonal tube and between the two stringers? To what and how is it attached?

Mike,

Since you are driving I see no reason we can't get together with Dennis at Mt View, that is easier to reach than Gaston's. All the fun of Gaston's is flying in unless you are an avid fisherman, then Gaston's is great no matter how you get there.

aeroncafan · Post by **aeroncafan** » Wed Nov 05, 2008 21:40

I need a friction adjustment knob for the trim control (part number 1-2390 in the 7AC Service Manual)...the big black knob in James' first picture. Anybody have an extra one or know where I can get one? Earlier, Joe suggested keeping an eye on eBay, not any out there now and don't see one in any of the usual catalogs.

james gevay · Post by **james gevay** » Thu Nov 06, 2008 08:20

Yes Gus, those are the pulleys you see attached to the right diagonal tube that runs foward to the bottom longeron.
It's a welded stud or rod, about 1/4" dia and about 1 1/2" long, that is threaded for a AN320-4 nut.
This next picture shows it a little more clearly.

I have some of the same comments about the persons that made some of the "repairs" I found on my Champ. But that's what you get with an inexpensive plane that was repaired on a budget years ago.
Good luck, Jim

gusc · Post by **gusc** » Thu Nov 06, 2008 21:08

Jim,

Thanks, that setup is clear now. I have no doubt that the stud is not on my airframe but I think I can use Adels to do the same thing or put a bar across both vertical tubes to hold the pulleys.

What I'm not sure of is if I can get the cables rerouted in a covered fuselage. And I have my doubts that they will then be the correct length.

These type of things drive me nuts. This airplane was only rebuilt in 2003!

It appears to me in your first photo that the cables are touching the fabric, surely that is not so?

What are the cables going through the white bar behind the pulleys? Are they antenna or electric cables? My Champ has no electrics whatsoever so I don't have much stuff running around inside the airframe.

james gevay · Post by **james gevay** » Thu Nov 06, 2008 22:01

Gus, the 2 longest "T" or mushroom shaped stringers that run over the cabin from front to aft sit up higher about 1/2" over the left to right formers, so there is some space there.
I think you are asking about the yellow and green piece of wood with 2 holes in it. That is the elevator cable guide, it's made of 1/4" lite plywood with 2 holes and a piece of micarta nailed to it.

If you look closely you can see on the top longeron where black tape is holding the lamp cord that runs back to the tail. I assume it came from the factory that way in case you wanted to install nav lights, I also had the wiring in both wings when I took them apart.

I couldn't think of the name of the material my wear strips were made of, I think it's formica.

My plane is a basic stone stock 7AC without any electrical system or extra wiring, and that's the way I'm keeping it.

gusc · Post by **gusc** » Fri Nov 07, 2008 21:16

Jim,

Thanks to your photos I'm about to get this mess straightened out.

I was able to thread the cables above the formers with the help of a long piece of heavy wire, now all I have to do is reconnect them.

This is beginning to be a problem and I will probably end up cutting a larger hole in the headliner. The small access hole just isn't big enough.

After taking a look today I saw that the crosspiece supported the elevator cables. In your photo they looked like antenna cables.

I also saw that my forward pulleys are where they are supposed to be.

The set of pulleys at the bottom of the rear spar carrythrough are extras added by who knows who?? I removed these when I placed the cables atop the formers. I have no rub strips there but may add some. I really don't think they will wear the former much but they might. The cables are so small and the tension so low and the movement so little.

The rub strips may be micarta but I think a strip of nylon will do just as well.

james gevay · Post by **james gevay** » Fri Nov 07, 2008 21:44

Probably any material like micarta, nylon or formica would work just fine, about 1/16" thick is all you need. You could epoxy it up there and clamp or use binders or something to provide some gluing pressure while it cures.
Good luck!

CptKelly · Post by **CptKelly** » Sat Nov 08, 2008 08:44

The wear strips are phenolic, I think.

Mike

Holcombe · Post by **Holcombe** » Sat Nov 08, 2008 11:57

The wear strips should be Delrin. It is a lot like Nylon, and I have seen plastic cutting boards that looked pretty good also. A/S has the stuff, though wiith trim cables and so little movement, none of us will live long enough to care what gets used.
I was horrified to see the "empanage uncovered" picture and find a set of pullies mid way back in a place I truely do not want to go. Has anyone ever lubed those on a finished plane, and how did you get there. I have a small suringe with about two feet of primer copper tube. I use a mixture of ACF-50 and Antisieze and get to places I can barly see. Have to be able to at least see and stuff a rag underneath to keep the mess under control.