Top Flite TOPA0712 - Manual (Page 9)

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surface at a slight angle you will be able to see the
plate through the covering.
❏ ❏
10. The fl ap and aileron will each require a black
nylon control horn. The fl ap control horn needs to be
modifi ed. Cut a control horn as shown. A high speed
rotary tool works well for this.
❏ ❏
11. Place an unmodifi ed black nylon control horn
onto the plywood mounting plate in the aileron in line
with the servo arm. Drill a 3/32" [2.4mm] hole through
each of the holes in the control horn. Drill only through
the plywood plate. Do not drill through the top of the
control surface. Mount the horn with four #4 x 1/2" screws.
❏ ❏
12. Install the modifi ed control horn to the fl ap.
However, the fl ap horn is rotated 180 degrees from the
direction the aileron horn was installed. Install the horn
using the same method used for the aileron.
❏ ❏
13. Each aileron and fl ap pushrod is made from
a 5-3/4" [146 mm] 4- 40 pushrod wire threaded on one
end, a threaded metal clevis, a 4-40 nut, a metal solder
clevis and two silicone clevis keepers.
❏ ❏
14. Screw the 4-40 nut and the threaded metal
clevis onto the pushrod wire. Attach the clevis to the
second hole down on the aileron control horn. Attach
the metal solder clevis into the outer hole of the aileron
servo arm. Center the aileron servo arm and the aileron.
Mark on the pushrod wire where to cut the wire. Remove
all of the pushrod wire components. Solder the metal
solder clevis to the pushrod. If you are not familiar with
soldering follow the “Hot Tip” that follows.
HOW TO SOLDER
1. Roughen the end of the pushrod with coarse
sandpaper where it is to be soldered. Use denatured
alcohol or other solvent to thoroughly clean the
pushrod.
2. Apply a few drops of soldering fl ux to the end of
the pushrod, then use a soldering iron or a torch
to heat it. “Tin” the heated area with silver solder
by applying the solder to the end. The heat of the
pushrod should melt the solder – not the fl ame of
the torch or soldering iron – thus allowing the solder
to fl ow. The end of the wire should be coated with
solder all the way around.
3. Place the clevis on the end of the pushrod. Add
another drop of fl ux, then heat and add solder. The
same as before, the heat of the parts being soldered
should melt the solder, thus allowing it to fl ow. Allow
the joint to cool naturally without disturbing. Avoid
excess blobs, but make certain the joint is thoroughly
soldered. The solder should be shiny, not rough. If
necessary, reheat the joint and allow to cool.
4. Immediately after the solder has solidifi ed, but
while it is still hot, use a cloth to quickly wipe off
the fl ux before it hardens. Important: After the joint
cools, coat the joint with oil to prevent rust. Note: Do
not use the acid fl ux that comes with silver solder for
electrical soldering.
This is what a properly soldered clevis looks
like – shiny solder with good flow, no blobs and
flux removed.