Elevator Rigging
I would suggest you wait
on elevator rigging until you
are done with the other things in the aft end of the fuselage. I would complete all the
electric wiring,
static system installation, and riveting the turtle deck skin. Once the elevator control
pushrods are in
place, there isn’t much space in the tail.
I
rigged my elevators from the back of the plane working
forward, starting at the elevators themselves and ending with the front
stick.
Start
by clamping the elevators in the neutral or
trail
position. You can put a drill bit or dowel into each alignment hole in
the end
of the stab and elevator and use a level if you still have the fuselage
leveled, or a straightedge if you don’t.
Another method, and the one I used, is to
clamp the elevator to the stab
with the top and bottom of the counterbalance arm skins even with the
top and
bottom stab skins. I
used a large wood
clamp to ensure it was aligned top and bottom.
Connect
the F-841 pushrod to the elevator control
horns, but
don’t connect it to the F635 bellcrank just yet.
First you will want to ensure the F-635
bellcrank is in the neutral position to allow you to adjust the lengths
of the
pushrods.
I measured 3 1/16 from
the F-808 bulkhead per the plans by
clamping a piece of angle across the back of the bulkhead, then
measuring from
it to the center of
the top hole in the F-635. I
also made a little “jig” using some washers
that filled the access
hole in the F-818 ribs and left a small center hole that I could align
with the
lower hole in the F-635. I
made sure a
short piece of threaded rod fit through the center hole of the “jig”,
into the
bottom holes of the F-635, and through the other “jig” on the opposite
side. With this in
place, and the measurement from
the bulkhead, I was happy that the bellcrank was neutral.
Now
that the elevators and the F-635 bellcrank
are both in
the neutral position, you can set the length of the F-841 pushrod to
align the
rod end bearing with the upper holes in the bellcrank.
Tighten the jam nut and install the F-841
pushrod to the bellcrank.
Connect
the aft end of the F-840 pushrod to the bottom of
the bellcrank.
Set the aft stick to the
neutral position. I
had the plane leveled when I did my elevator rigging, so I
used a
level on the side and front of the stick to ensure it was
neutral. Then
adjust the length of the F-840
to align with the aft hole in the WD-412A lower rear stick. Tighten the jam nuts and
tighten the bolts
for the F-840. Those same two holes I used for the “jig” allowed me to
use two sockets
and short extensions to tighten the nut on the aft end of the pushrod.
Now you can insert the
F-839 pushrod and front stick. You
can again use levels to set the front
stick to neutral, or just measure from the top and bottom of the rear
stick to the
top and bottom of the front stick.
When
the two measurements are the same, the sticks are neutral.
If you haven’t already
bent and/or cut the front stick,
remove it before checking the freedom of movement of the controls. It will hit the instrument
panel if you
don’t.
Unclamp everything and
check full range of motion. Check
that the elevators move to the up and
down stops and that they are traveling within 25-30°
up and 20-25°
down.
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