Trim cable installation

Yesterday we began our real work on the airplane. Not that the first two weeks  at Robby’s weren’t real, the definitely were. I mean the real work, at home, unsupervised.

Spork and I finally have begun our serious work on trying to get something done each day, or at least most days of the week. We started with a half day of work on Sunday, after feeding and rigging the kids new toy.

18' Renken sailboat, just needs trailer work
18′ Renken 1994 sailboat. Perfect for the kids to go on adventures with

A guy offered me an even trade for something I desperately wanted out of my way and off the farm. The kids are super excited.

But back to the other expensive hobby, airplanes. And we began our new works schedule with the trim cable. We originally didn’t think we’d install the trim cable, instead opting for a trim servo on an autopilot, but it turns out the TruTrak autopilot doesn’t use a trim servo, instead controlling the push rod directly. That meant we were back to plan A of installing the factory trim cable and control.

On one of our short work days we’d had prior, we’d installed the trim mount plate on the elevator (which involved taking the fabric off, sigh). We’d also temporarily run the cable from the tail to the cockpit. We started at noon and worked till five pm. 80% of that time we spent trying to figure out one piece of hardware or running to Lowes to pick up tie straps to hold the cable. But more about that later.

Installing the trim control plate
Installing the trim control plate

Spork drilled out the tabs to the correct size, and I installed the four rivets required to hold the plate in place. Luckily I had a good picture of how the plate installed from when we were at Robby’s place back in March.

Trim plate in Just Highlander at Robbys place
Trim plate in Just Highlander at Robby’s place

What I didn’t know, and couldn’t see in this pic, or the pic in the manual, was what was the piece of hardware that attaches to the cable you see at the bottom of the trim lever. Obviously something holds that cable securely but it wasn’t noted in the build manual. I spent an inordinate amount of time trying to find it in the manual on another page maybe, going and getting the build manual CD and trying to look at it on the shop computer. No go, no Open Office on that computer. So I tried on the farm store computer. No Open Office on that one. “Google: How to I view a Microsoft Word document on a Mac?”

Turns out Pages, a Mac product will do what I need. But that isn’t installed, so start the download. Once it finishes, hit install. Nope, don’t have permission. Ugh. Log out, log in as me (after a few password failures) and finally install Pages. Pull up the correct file, scroll to the picture of the installation of the trim system. Figure out how to blow up the picture, and…it…is…blurry. Argh!!!

I can’t find a picture of the hardware required and it is not in the build manual. I’m working on Plan C when I finally break down and text Robby the following picture and a question.

Elevator and trim tab, with cable ready to be mounted
Elevator and trim tab, with cable ready to be mounted

“What hardware do I use to mount the cable to the trim tab?”

5 minutes later I’m on the phone with Robby and he describes the hardware to me. He knew what it was instantly. He also says he’ll send me some pics of his install so I can see what I’m doing. He is super knowledgeable and super helpful, as always. In hindsight, I wish I’d asked him first, but I try to be self sufficient as much as possible. That is the only way to learn.

Robby's trim tab on his airplane
Robby’s trim tab on his airplane
Better view of the special nut that secures the cable
Better view of the special nut that secures the cable

Before his photos had even shown up, Spork, armed with a brief description of what we were looking for, had already produced the missing hardware.

The mystery hardware, found
The mystery hardware, found

With hardware in hand, we made rapid progress on the trim system. We cut the sheath and cable to length, temporarily routed the cable through the fuselage, secured the cable at both ends, and mounted the trim lever itself.

The next step is to take the trim lever off and bend it for clearance as it is in Robby’s install.

Robby's trim system in his SuperSTOL
Robby’s trim system in his SuperSTOL

We’ll also bend the cable itself so it runs true, just like Robby did. None of these steps are in the build manual, something that continues to frustrate. It makes perfect sense to make these modifications, but when it is your first build you don’t know what is acceptable and what is not, you don’t just start bending things to make them fit. Can I bend a control cable like this? Is there a certain degree of bend that is ok, more weakens the metal? No idea. But with good pictures of a proper install, like I have above, now I know exactly what to do and it is easy.

I probably have 6 hours in this install. If I had to do it again at this point, I’d have it done in 20 minutes. Such is the way of airplane building.

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