Hook Up The Throttle - GREAT PLANES Waco YMF-5 Instruction Manual

Hook Up the Throttle

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1. Using a long drill bit, drill a 3/16" [4.8mm] hole through
the firewall in line with the engine's throttle arm. Offset this
about 1/4" [6.4mm] up to allow for the ball link that you will
need to attach to the throttle arm.
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2. Dry fit the 24" [610mm] gray outer pushrod tube in
the hole you just drilled. Slide the pushrod tube through the
access holes in the formers and back to the servo tray.
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3. Prepare the throttle servo by choosing the servo arm
that is 90° to the servo case at 1/2 throttle. Clip off the unused
servo arms. Drill the outermost hole on the arm using a 5/64"
[2mm] drill bit. Then, fit the servo arm onto the servo. Install
the throttle servo in the servo tray so that the end of the
servo arm is in line with the pushrod tube. Harden the screw
holes with thin CA.
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4. Position the inside end of the pushrod tube about 4"
[102mm] from the servo. Cut the pushrod tube 3/8" [9.5mm]
forward of the firewall. Fit the wooden pushrod tube standoff
inside the fuselage at the former that lines up with the leading
edge of the lower wing. Remove the pushrod tube and sand
the outside of the tube at the place that you marked and at
the firewall end of the tube.
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5. Glue the pushrod tube in place at the firewall using
epoxy.
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6. Thread a ball link onto a 1" [25.4mm] threaded rod so at
least 1/4" [6.4mm] of thread is engaged in the ball link. Thread
the other side of the rod into the white inner pushrod tube so
that 1/4" [6.4mm] of thread engages in the pushrod tube.
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7. Drill and tap the throttle arm on the engine using a 2-56
drill and tap set. Thread a 2-56 ball link onto the throttle arm
using thread locking compound on the screw threads. Install
a 2-56 lock nut on the back side and tighten the ball link and
lock nut onto the throttle arm.
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