Section 6: Installing The Rudder And Elevator Servos - Hangar 9 Sukhoi SU-31 Instruction Manual

Section 6: Installing the Rudder and Elevator Servos

Parts Needed
• Fuselage
• Servos w/mounting hardware (a minimum of 80 oz in of torque) (4)
• 1" Heavy-Duty Servo Arms (2)
(HAN3574-JR or HAN3575-Futaba)
1
• 1 / " Heavy-Duty Servo Arms (2)
4
(HAN3578-JR or HAN 3579-Futaba)
If using a computer radio:
• 24" Servo extensions (JRPA102) (4)
If using a non-computer radio:
• Y-Harnesses (JRPA133) (2)
• 18" Servo Extensions (JRPA099) (4)
Note: If using a non-computer radio, one of the servos
used for elevator must be a reversed-direction servo.
See the "Radio Setup" section for more details.
Tools and Adhesives Needed
• Phillips screwdriver
• Screwdriver (small)
FAST FACTS: The rudder and elevators require a minimum of
80 oz in of servo torque. Using servos with less torque could
cause a crash. In the prototype 1/3-Scale Sukhoi Su-31, we used
JR8101 and JR8411 servos with excellent results.
Step 1. Locate and center the two elevator servos and install 1"
heavy-duty servo arms. Center the two rudder servos and install
1
1 / " heavy-duty servo arms onto the rudder servos.
4
Note: If using a non-computer radio, one of the elevator
servos must be a reversed servo.
Computer Radio
Step 2. If using a 7-channel or greater computer radio with
mixing (highly recommended), install four 24" servo extensions,
one on each servo. Tie a knot at each connector and tape to prevent
inadvertent disconnection.
18
Non-Computer Radio
Step 2a. If using a non-computer radio, install four 18" servo
extensions, one on each servo. Tape and tie a knot at each
connector to prevent inadvertent disconnection. Install one side
only of the two Y-harnesses to two of the servos, also tying
knots to prevent disconnection. The other two servos will be
hooked up to the Y-harness when installed in the airplane. One
elevator servo will need to be a reversed-direction servo.
Step 3. Install the servo hardware (grommets and eyelets) on
the rudder and elevator servos. Install the elevator servos in the
fuselage tail section with the output shaft forward. The rudder
servos are installed with the output shaft to the rear as shown in
the photo below (elevator in the upper opening and rudder in the
lower opening). Mark the locations for the mounting screw holes.
Note: If using a non-computer radio, install one of the
servos with the Y-harness attached in the top opening
(elevator) and the other servo with the Y-harness
attached in the bottom opening (rudder). Install the
other servos in the opposite side of the fuselage being
sure to connect the servo to the other open connector of
the respective Y-harnesses. Don't forget to knot and
tape the connectors.
Step 4. Mark the locations for the servo mounting screws and
drill pilot holes at the marks using a 1/16" drill bit.
Step 5. Secure the servos in place with the screws provided
with your servos.