RadioLink Electronic Limited
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Propellers installation can be skipped as the whole F121 is already assembled by factory default. If the
default propellers get worn and needs to be replaced after a period of flight, it is important to well identify the
rotation direction of propellers. If installed incorrectly, F121
can’t take off even the throttle is pushed to max.
In order to identify the propellers rotation, take a propeller and observe there’s a radian at both sides of the
small cylinder in the middle. The higher part (also called windward side) of the right propeller is at the front and
the rotating motor will make propeller rotate counterclockwise(CCW). On the contrary, that is clockwise(CW)
rotation. For the 65mm GEMFAN propellers used on F121, there are two marked with a letter R, meaning they
should be installed on the motors of clockwise.
When the installation is done, make sure the four motors are vertical to the aircraft frame. Adjust them to
vertical positions if necessary, otherwise F121 may not flight successfully.
3.3 Power On F121
Before powering on F121, fully charge the 1S LiPo battery first. Plug the PH2.0 end of the battery into the F121,
then insert the battery into the battery frame under at the bottom of F121.
(1) Orange propellers indicates the head of F121 by default. make sure they point to the same direction as the
pilot when powering on and be ready to fly, to ensure safety.
(2) The green LED of F121 will begin flashing when powered
on. When it’s off, it means F121 finishes
calibration.
Note
Head direction is determinate. If F121 is calibrated with the direction different from the default, it will turn
back to the default
direction automatically when starts flying, That’s what we called Head Front Forward Point
Without Compass.
3.4 Flight Note
If it
’s the first time of flying drone, flight mode of Altitude Mode-Low Speed is strongly advised to set. At the
altitude mode, when toggle the throttle upward till the drone reaches a certain height and release, F121 will
