O.S. Engines 91HZ-R 3C - Manual (Page 10)

18
1.
2.
The Needle Control Arm enables the pilot to make
the necessary needle adjustment by means of one of
the auxiliary levers on his transmitter while the
helicopter is in flight. Then the following useful
corrections can be made.
Needle can be adjusted to optimum setting while the
helicopter is in flight.
When the needle is set too rich or too lean during a
performance at a competition, the needle can be
adjusted via transmitter in flight.
When the r.p.m. increase as the fuel tank changes
from full to almost empty, the situation can be
corrected by opening the needle.
Note:
In order to use this Needle Control Arm , an
additional servo and a linkage rod are required.
Features:
ABOUT THE NEEDLE CONTROL ARM
Cap Screw
Ratchet Spring
Needle Control Arm
High Speed Needle Valve
It is not always necessary to install
the needle control arm
How to install
Remove the high speed needle taking care not to
damage it’s point.
Install the control arm on the needle with a M2.6x5
bolt supplied.
19
1.
2.
3.
Connect the Needle control Arm lever and servo
horn with the linkage rod. Set the linkage so that
the Needle control Arm lever and servo horn
makes right angle at the center of servo stroke. 3.
approx.
14-16mm
The throw angle of the servo horn should not be
more than 45 degrees both right and left. Use a
hole approx.15mm from the center of the servo
horn.
Servo
Servo Horn
Linkage Rod (commercially available)
Equal distance
Close the high speed needle slowly to fully closed
position. Then, open the high speed needle two
turns and remember it’s position.
Switch on the transmitter and then receiver. Check
all the movements. Confirm moving direction of the
servo vs. transmitter stick travel volume direction.
Move the transmitter stick travel volume fully in the
direction which opens the high speed needle.
Connect the linkage rod, and install the control arm
on the high speed needle.
ADJUSTMENT
45 degrees 45 degrees