Trim Turnbuckles

[PaulSA]

I ordered the Wicks hardware package with my kit. I am in the process of fitting the control cables to the rear. I have one lighter gauge pair of turnbuckles which are obviously for the 1/16" trim cable. I would have expected these to have a "cable" fitting at each end. However, mine have one clevis end. So, either Wicks have sent me the wrong part or I am missing something. Looking at it, I could probably fit this turnbuckle directly to the trim horn - which would make for a neater installation. There appears to be enough space to do this without interfering with the elevator horns.

Anyone done it this way or wish to comment?

[jaredyates]

I'd hate to have to safety wire a turnbuckle back there, even with a big access hole. Mine is just aft of the cargo area. Don't let the Wicks parts drive your choices... Verify each piece and make changes as necessary.

[PaulSA]

Aft of the cargo bulkhead is where I was going to put them. I'll order a couple of new ones with cable ends.

[jaredyates]

You can buy the cable ends separate from the turnbuckle body, and you should only need one turnbuckle per airplane.

[SimonNicholson]

I have just finished my trim and no turnbuckles used. I am not saying that is how it's done, just how I did it.

[jaredyates]

How did you do it without a turnbuckle?

[Mark Goldberg]

The trim cables need to be pretty tight. Not sure also how you could accomplish that without turnbuckles. Mark

[Battson]

I have just finished my trim and no turnbuckles used. I am not saying that is how it's done, just how I did it.

How are you going to disassemble and reassemble + re-tension it for maintenance? Even the pre-stretched cables will still stretch some more over time, and will need to be tightened up....?

As a rule of thumb, I think you want a turnbuckle in every cable run. I have adjusted every single one in the last 4 years.

[Bcone1381]

you should only need one turnbuckle per airplane.

Jared, I had not thought about this..... Are you saying that since the trim is a continuous loop, that one turnbuckle is all thats required to adjust the cable tension?

[Mark Goldberg]

That is correct. MG

[Battson]

Jared, I had not thought about this..... Are you saying that since the trim is a continuous loop, that one turnbuckle is all thats required to adjust the cable tension?

In the case of the trim system, that is true.

The same cannot be said for the ailerons. Each of the three cables needs a turnbuckle to tune the rigging correctly.

[Bcone1381]

Thanks Battson.

[SimonNicholson]

Did you put them on the wheel end or the horn end?

[Mark Goldberg]

Generally - it is good to keep weight forward if you have a choice. While one turnbuckle will not be much weight - every little bit counts. Mark

[jaredyates]

I put the turnbuckle in the middle, just aft of the cabin. While the big control cables end up being relatively loose at 20-30 pounds, the little trim cable ends up being much tighter. I flew with mine too loose for a while at the beginning. Eventually we loaded up for a heavy trip and found that the nose down trim was creeping out every few minutes. Fortunately I had enough safety wire in my travelling tool kit to tension the turnbuckle in the field, saving me from having to fly out of trim for a second leg.

[PaulSA]

I keep hearing the trim cables need to be "tight" - anyone give me a number?

[Mark Goldberg]

Paul - there are FAA specs for the tightness of control cables. Probably in AC43-13. 1/8" cables have a different spec than 1/16" cables on the trim system. I do not know the spec. But generally the trim cables need to be tight. MG

[jaredyates]

Mine are in the range of 100 pounds, but I'm not a referable source.