42
The rudder control horns have already been mounted on the
rudder. You will make up two sets of linkages.
Step 20.
Scrape or clean the ends of each piece of music wire.
Using a soldering iron, silver solder one of the threaded couplers on
one end of each piece of music wire.
Note:
It’s important to bend
over approximately 3/8" of the music wire onto itself at the ends
using some pliers. This will give a more secure mechanical solder
joint as the silver solder has more to “grab onto” than a straight end.
Step 21.
After the solder has cooled, check the security of the
solder connection by pulling on the connection. Attach a clevis on
the threaded coupler and thread the other end through the fuse-
lage. Attach the clevis to one of the rudder control horns. Do the
same with the other pull-pull linkage.
Step 22.
Trial fit one of the linkages to the servo arm of the rudder
servo, compensating for the fact there will be a threaded coupler
and clevis attached. Once you’re satisfied with the length, silver sol-
der the threaded coupler to the music wire as described in Step 20.
After the solder has cooled, again check the security of the joint.
Make up the second linkage using the previous procedure. Once
both linkages have been constructed, trial fit in place by installing
the clevis on each linkage and connecting to the control horn of the
rudder servo. Final length adjustments can be made at either or
both ends of a linkage by screwing the clevises in and out as need-
ed. You can also move the clevis closer in or further out on the
horn/arm. Be sure to use 5–7mm sections of fuel tubing over each
clevis to prevent accidental opening. Note that we have removed
two of the servo arms to allow more freedom of movement.
Step 23.
To install the engine throttle linkage, you will have to
remount your engine, unless it is already mounted. To install the
throttle pushrod, locate the 19
3
/
8
" rod that is threaded on one
end. Install a clevis onto the threaded end 16 turns. This will be
used to connect the throttle arm to the throttle servo. Trial fit the
rod and note where it will pass through the fuselage formers.
The location of the opening in the firewall for the pushrod will
depend on the type of engine installed. We will use a Saito 1.50
four-stroke engine to illustrate the steps for the installation and
adjustment of the throttle linkage. Once you have determined the
linkage path, use a 1/8" drill bit to drill a hole in the firewall and
fuselage formers as necessary. A 1/8" hole should provide
ample room for linkage operation.
Caution:
Do not drill
through the fuel tank.
Step 24.
Thread the throttle control rod through the firewall
unthreaded end first. Attach the clevis to the engine throttle con-
trol arm.
Section 15: Installing the Control Linkages
3/8"
threaded coupler
CONTINUED
3/8"
