Trim Cable slipping.

[Greg Bockelman]

Mike R. maybe you can answer this,

But I am throwing this out to the group.

I can trim nose up just fine, but the crank pulley slips on the cable for nose down. How can I adjust this? Is it just a matter of increasing the tension on the spring?

[jgerard]

Re: Trim Cable slipping.

do a search on "trim cable" and you will find a TON of info on this subject

[crispy critter]

Re: Trim Cable slipping.

You might be getting the cable too tight . The problem is when the pulleys get some age,dirt,and wear in them they get stiff where they should be loose and free and the pulleys become slick and hard(kinda like crystalized brake pads). The easiest way to fix this problem is to remove the trim pulleys(yes,front and rear) clean the jack screw and everything on the rear pulley system(may require a little fabric work unless you can spary something back in there that will loosen it up enough to work smoothly again).Clean your cables good and make sure they are clean and free of any grease or lubricant,and you can soak the pulleys in solvant over night to help soften them back up a little bit..use cleaning solvant because it won't eat at the pulleys and it will not leave a slick film when it dries. When you put everthing back together make sure you DO NOT use any type of oily lubricant on the trim system .Always use graphite on the trim system. The graphite lubricates and gives the cable traction on the pulleys.
You might try using some starter fluid or brake cleaner to clean the cables and pulleys good without removing them,then put the graphite to it,but be very careful with the starter fluid and barke cleaner because they are VERY flammable!!!!! They can also be hard on your fabric if they are soaked from the inside out. I advise you not to use those as pulley/cable cleaners because of the flammability...only use them at your own risk. Now that my ass is covered .....they do work.

[Ragwing nut]

Re: Trim Cable slipping.

Make sure the cable has not slipped on the elevator pulley and got the stops out of place. If it has, it will allow it to go one way and not the other. I never needed to move it more than 2 turns either way without problems. If so you will need to loosen the cable and reset the trim stops.

Mike

[Greg Bockelman]

Re: Trim Cable slipping.

OK, Basic mistake. Note to self. Use search function.

Having said that, does anyone have a good diagram for the trim system? The "Manual" I have does not show it clearly if at all.

[Ragwing nut]

Re: Trim Cable slipping.

Simple loop between 2 pulleys ran through guides, there is 2 cable clamps just behind the headliner zippers that act as cable stops. Also there is 2 more clamps between the other 2 that have a spring attached to them which holds the tension for the cable.

Unzip the back headliner, verify trim is neutral, then see if the cable stops are in the middle as well. If not, you will have to loosen the tension on the cable and reset the stops. I have in the past on other t-crafts grabbed the cable and forced into place without releasing tension when I was somewhere with no tools, but don't advise it.

Mike

[Forrest Barber]

Re: Trim Cable slipping.

forced?? WE "gently slip it into place" I have slipped the cable off the rear pulley many times with a bent piece of welding rod to realign the system, noting where the cable is and then turning the rear pulley to match. Also note that the pulleys were kind of V groved when manufactured and they get a U groove with wear. Rumor has it that some folks V them again with a V file... Clean is good , some have even used bow rosin from a violin.

[Greg Bockelman]

Re: Trim Cable slipping.

OK, question about the trim stops. Are they at each end of the spring, or are there supposed to be some in another spot?

I am going to try the rosin thing next time I go out.

[alwaysoar]

Re: Trim Cable slipping.

I used fan belt dressing when my was slipping. Little spray can, worked great. Tried a hunk of rosin but too hard to get on to cable. I don't know why it works, it's not sticky and it doesn't make the trim work harder. So try it, it's harmless, cheap, easy, and it worked for me.

[Wayne]

Re: Trim Cable slipping.

The rosin does help a lot. Academy Sports is a good sourse.

[Len Petterson]

Re: Trim Cable slipping.

1 make shure you have good tenson on the spring.
2 oil in the little hole in the elevator front tube. On the left side just by the fin.
3 rasin helps to a degree.

I dubbled up the spring, just make shure it can not catche any there.
It make for hard to control when trim freezzes in nose up possition and you have to puch down with both arm.
If it happens: Back of on the power as soon as you can level of and the trim maybe move! worked for me!

Len

[Ragwing nut]

Re: Trim Cable slipping.

There may only be two on the cable, one at each end of the spring. It had been a few days since I had my head in there. Just make sure they are in the middle of the travel when the tab is neutral.

Mike

[Greg Bockelman]

Re: Trim Cable slipping.

There may only be two on the cable, one at each end of the spring. It had been a few days since I had my head in there. Just make sure they are in the middle of the travel when the tab is neutral.

Mike

They are. It is slipping on the crank pulley.

[jdoran]

Re: Trim Cable slipping.

A good pre flight practice is to hold the yoke in the neutral position, and crank trim full up and full down. Do it every time- it only takes a few seconds.

This has really helped my trim stay in shape, because I personally don't use it much while flying, and the lack of use causes the jack bolt to freeze up.

John