Teresa got a new outfit, in a color she doesn't normally wear... mint green!
She reminded me of chocolate chip mint ice cream in this picture. :-)
OK, back to where we left off on
Friday, with the leg-leveling feature for the workbenches. My first
step was to make sure all legs were exactly the same length... I turned the tables
over, measured up from the floor 36.5 inches on each leg, and used the square to
draw a line around the leg at that height. Next, I used a clamp to secure
my square 3 and 15/16" below that reference line. The square served as a rip
fence for my saw, to cut off the leg at the same height on both sides (the saw blade's
depth would only get through one 2x4 at a time, so I had to cut each leg twice,
once from each side). The square clamped to the 2x4 helped keep everything
"perfect".
I fastened the steel plate to the bottom of the 2x4 with some lag bolts, and drilled
a deeper center hole that allowed the threaded furniture foot to go deeper into
the wood leg, as needed. The plates were longer than necessary, so I made
sure the "excess" always went to the inside of the table--nothing for anybody to
nick an ankle on... that would hurt!
I purposely chose furniture legs that were not round... I wanted to be able to grab
and turn them with channel lock pliers once they have the weight of the table on
them.
Once the tables were turned over, I leveled them in several directions, and they
no longer have the slightly perceptible wobble they had before, and the seam between
the two tables is FLUSH.
Here's the new configuration for building the empennage...
I clamped the two tables together from underneath, so they'd stay that way.
Lindsay and I took a quick run to Home Depot for some new protective boards to cover
the workbench... as you work on the airplane parts, you drill through the metal
and into the table-top, so unless you want your workbench to be full of holes, you
cover it with some other board. I found a $5 sheet of 3/4" particle board
in the salvage pile due to a damaged corner, and Home Depot cut it into two 2 foot-by-5
foot sections for me, neither of which were affected by the damage. Sweet!
Covered the workbenches on a 5-note!
One of the first steps of the empennage tells you to "break" the corners of the
rear spar stiffeners. Basically, since these will be inserted into a channel
that has rounded edges, you need these stiffener bars to ALSO have rounded edges,
as you can't stick a 90-degree piece of bar stock into a rounded corner. I
took a vixen file and it worked great... here, I've done one of the four edges....
This is after the rough cut. After smoothing it out with emery cloth and a
scotchbrite pad, it was SMOOTH.
Lindsay was sneaky and got a picture of me filing the spar stiffeners.
Here you can see how the plans ask you to round off the ends of the spar stiffeners.
The top one has not been done, the bottom picture shows one I've rough-cut.
You can see the "rough edges" from the vixen file--those sharp edges will get smoothed
out before I'm done.
And here's one unfinished stiffener bar on the left, along with a finished, smoothed,
polished one on the right.
A closeup of the ends, comparing finished stock with unfinished raw stock (on the
bottom).
I was amazed at how much gray aluminum oxide "dust" was generated while using the
emery cloth and scotchbrite pads to remove the machining marks on the stiffener
bars. And this picture was taken AFTER I had vacuumed and used air to blow
off the top of the workbench. The stiffener bars will fit inside (and join)
the two aluminum channels you see in this photo, forming the rear spar of the horizontal
stabilizer.
After finishing smoothing out all the work on the rear spar stiffeners, I clecod
them in place and match drilled out all the holes to #30 size.
I wanted Teresa to have a part in the first pieces we built, so she took a break
from fixing dinner and came out to drill out the rest of the holes...
There are four holes (the eighth ones inboard from the ends) that get drilled out
further, to #19, where an internal rib will also be riveted to the spar. Then,
you attach and match drill the elevator hinge brackets....
Then, I fabricated the center elevator hinge bracket, including the ball bearing around
which the elevator will pivot. Only one of the halves of this bracket is pre-drilled,
so you clamp the two halves together with the bearing in the middle, and use the
pre-drilled half to match drill the other side. I used a pin-punch to make
sure the bearing was accurately positioned before drilling it out.
The instructions tell you to drill out the rear four holes (and put clecos in those
holes) while it's clecoed to the spar, then remove the assembly and drill out the
remaining two holes. It took me a minute or two to figure out that the "rear
four holes" would be the top four holes in this orientation... when the spar is
vertical, in it's final position, this bearing and bracket would be pointing to
the back of the airplane, and the 'top four' in this orientation would be the 'rear
four holes'.
I drilled out those holes and inserted clecos as I went. I had to remove the
two vertical clecos you see in the picture above in order to gain access to drill
out the two side holes. I then removed the whole assembly from the spar and
drilled out the remaining two holes. I carefully marked the bracket and bearing
position so I could reassemble it the same way later, then took it apart and deburred
all the holes. I cleaned the parts with MEK and sprayed some self-etching
primer on them.
After dinner, I came back and squeezed the six AN470-4-5 rivets in place, and we
have a completed assembly!
Another view from the side. The instructions said you could prime the bearing
if you wanted... I figured "what the hey...". I was a little worried it wouldn't
spin if I painted it, but I notice no loss of motion. This thing is SILKY
SMOOTH.
I clecoed it back to the spar, and that's it for tonight. I started working
on the plane about 3:30 today and finished at 7:00, so we're now 3.5 hours into
the build process! Can I start making airplane noises now?? :-)
TOTAL BUILD TIME TO DATE: 3.5 hours.