Assembly

8/5/11
Hours: 9.5
Assembly: 23.0

Several little things here.  First, the wiring for the electric trim-tab servo is now complete and waiting for a cable to be plugged into it.  This of course will happen a very long time from now when the airplane is almost complete.  But I took some time to make it easy on myself later.  I bought some nice locking connectors, soldered the wires in place and mounted the connector in a spot which will make it “easy” to reach when the trim tab servo is mounted.  One thing I learned is that in the future, I’m going to get a wire crimper and connectors that take crimped pins rather than the solder cups.  Once the wires are soldered to the cups, it’s not possible to get the heat-shrink tubing around it.  This wasn’t a problem here since I slid the heat-shrink tubing on before soldering, but in the end, I could have used longer tubing for a better look and then another, larger diameter heat shrink tube over that whole thing to give it some more strain-relief.  This one is fine, but in the future, I’ll be crimping instead of soldering.

Also included the pin-out right here in this blog so that I’ll always be able to find it when I need it.  I do have the sheet I took the picture of in my airplane folder, but just in case I lose it, it’ll be here too.

Then Scott and I got the elevators fully attached to the horizontal stabilizer.  This was described in a previous post.  It was more of the same.  But now the job is finished.  Both elevators are aligned and had holes drilled into the control horns, etc.  They’re ready to go when we’re ready to go.  One thing I had to do was figure out how many turns the bearings could be backed out and still be safe.  I found out that they need to be fully engaged to the nut-plate that they screw into.  That means that all the threads have to be in play, so to speak.  I found this position by counting threads.  There are 6 full revolutions of threads in the nut plate.  This means that after 6 full revolutions of the bearing, all threads are in play.  This is the point at which the bearing can’t be backed out any further.  I then turned them in and counted the turns until the starting spot as indicated by the plans were reached.  I counted 1.5 turns.  To get the elevator to swing freely over the full range prescribed in the plans (30 degrees up and 25 degrees down) we pretty much had to back all but one of the bearings out that 1.5 turns.  When I checked up on this, I discovered that many of the other builders had the same experience.

Finally, I got back to the trim-tab anchors.  The plans call for these to be riveted to the cover plate.  But long ago, I decided to buy better anchors (it is agreed by most everyone that the anchors supplied in the kit are pitiful – just a nut welded to a flat piece of metal).  And apparently with these anchors, it’s very difficult to install the trim tab cables.  So others have done similar things to what I did.  I bought some self-locking pem-nuts (actually, I got them as samples from the manufacturer) and made little nut-plates to fit over the holes in the anchors.  I wanted to press the pem-nuts right to the anchor, but the hole required would have been too close to the edge of the anchor, so I made nut-plates with scrap aluminum and the pems.  Then I riveted these nut-plates to the anchors and voila, I have removable anchors.

Then I’m about to put the lower fairing on the rudder.  Because I want to put some navigation lights back here, I don’t want to permanently install the fairing with pop-rivets.  I found some people on-line who used nut-plates installed on the fairing in order to make it removable.   I have all the parts and will be doing that probably over the weekend.  Then it’s just build a cradle for the wings and wait for the wing kit to arrive.

No comments:

Post a Comment