I haven't had time to do any updates lately, although I have been getting some work done on the plane.
I just realized I hit the one year anniversary of working on the fuse. I'd hoped it would go more quickly, but there have been too many side things crop up. Sometimes life gets in the way - you just keep plugging along as you get time.
In the last few weeks I've installed the manual trim cable (which is a vernier unit similar to a mixture control, but the rapid movement part is disabled), mounted the horizontal stab and match drilled it to the fuse, drilled the elevator horns, fabbed and mounted the elevator counterweights on some other miscellaneous stuff related to the empennage.
First thing to do was install the elevator bellcrank. It's mounted between a vertical brace and a floor rib right behind the baggage wall.
The bellcrank has a bearing in the center and one arm is longer than the other. Long arm hooks to the elevator pushrod, the short end connects to the pushrod that goes forward to the control yoke. Rod end bearings are attached at the end of each arm to make everything very smooth.
The long (and fat) elevator pushrod is attached to the rod end bearing and continues aft through a hole in the aft bulkhead where it will attach to the elevator horns.
Also decided to run the rudder cables since this seemed like a good time. I'd heard of folks having problems with these, but they were easily inserted by hand if I popped out the nylon bushings. There were a few tight (or closed) spots where I couldn't pop out the bushings, and even then it wasn't terribly hard to work the end of the cable through the bushing.
I used a long grabber tool to pull the cable through the already attached baggage compartment wall. I pulled a small rope through, attached the rope to the cable, then used it to pull the cable through.
Aft end of the rudder cable. It will be clamped to the aft fuse skin using an Adel clamp where the dimpled hole in the skin is.
This is another shot of how I pulled the cable through the sealed baggage wall.
Next I installed the trim cable. I had it pulled all the way aft before I realized I'd forgotten to thread it through the attach plate. Kicked myself a second, then realized it had to come apart somehow.
Thankfully it does. If you open up the vernier end, this is what is inside. Similar to a brake/clutch cable on a motorcycle. Slide the ball out of the socket and it comes right apart. Whew!
The aft end of the trim cable is a bear to get through the horizontal stab structure - some very tight corners and bends, and the cable is pretty stiff.
I ended up using my tubing bender spring trick to thread it through all the holes. Worked very well.
I'd forgotten (or decided to skip) the installation of the elevator up stop. I needed it, so I fabbed it up and drilled/riveted/bolted it in. It gets primed and riveted, just forgot to take a picture at that point.
The trim cable attaches to a nut welded on to a small square of sheet steel. That gets riveted to the trim access cover on the bottom of the left elevator. I'm laying it out for drilling here.
Once it's drilled, you screw the nut on to the trim cable, cleco that to the trim access cover, then work all that into place and screw it down.
I forgot to take a shot of it, but there is a clevis that threads on to the end of the trim cable that attaches to the actuator tab on the bottom of the trim tab.
Here's everything in place. Discovered something very handy when I was working out all the dimensions and where to set everything to get it centered.
The vernier cable (mine at least) is exactly 10 turns stop to stop. So by going 5 full turns from either stop, I know the cable is dead centered. I should be able to use that to establish some number of turns from center to set takeoff trim.
I'd wondered how it was done - this seems like it will be very easy to do.
Next thing to check was the trim limits. This is full up (I know the tab is down, but that's how you get up elevator).
Full down trim. Both up and down worked out to almost exactly 35 degrees. This is more than Van's specifies. I may either have to limit it physically or just not use it all.
In practice, you only use what you actually need anyway, so I can't imagine too much would be a problem.
The autopilot I will use is not trim based, so that's not an issue either.
Next thing to work on was the vertical stab. I spent more than 2 hours measuring, clamping, re-measuring, plumbing with a plumb bob, measuring some more..... I did not want to have either this or the horizontal stab wrong. Makes for a hard to trim plane, which I do not want.
After measuring what must have been 50 times at least, I finally drilled the holes through the F912D elevator stop that establish the vertical stab height as well as setting vertical.
Next is to match drill the forward vertical stab spar to the offset attach plate. It's offset to account for P-factor I suspect. I drew center marks on the spar and plate to make sure I got it square. It's pretty disconcerting to see how far it's offset, although truthfully it's not that much, but you can definitely see it when you look at it looking aft.
At this point I haven't finished final mounting the vertical stab - I just worked on aligning the rear spar of the vertical stab dead straight, then worked with the rod end bearings (there are 3) in the rudder to line them all up with the hinges as well as make sure the gap at the counterweight arm was even. Time to call it a night.
