FeiYu Tech FY-21AP User Manual

Page 4

GuiLin FeiYu Electronic Technology Co., Ltd http://www.feiyudz.cn E-mail:

We do not recommend using your transmitter trims to level your aircraft in Auto Balance
mode, as the new trim settings will affect your aircraft when you revert to Manual Mode. It is
best to land and adjust the FY-21AP installation.

FY-21AP Pre-Flight Checking and Debugging

PRE-FLIGHT CHECK:

The following procedure explains how to check for correct servo control direction upon FY-

21AP activation. You should also check that the FY-21AP does not control the aircraft servos when
in Mode 1: Deactivated Mode.

STEP 1: DIAL ADJUSTMENT

Adjust the three dials on the FY-21AP so that the arrow is in the middle, as shown below. Then

rotate all dials in one direction (does not matter which direction):

STEP 2: STABILIZED MODE

Place the plane on a horizontal surface with both the wings and pitch leveled. Centre the rudder

surface. Move your radio 3-position switch so that the FY-21A is in Mode2: Stabilized Mode.

EP 3: AILERON CHECK:



Incline the plane to the right (roll right). The ailerons should give a control signal to counter
this roll direction (see below). Same as when rolled to the left. If the ailerons move correctly,
the knob has been turned in the right direction. You can now adjust gain by moving nearer (low
gain) or further away (high gain) from center:



If the ailerons do not follow the movements shown above, simply turn the aileron knob to the
opposite side (beyond centre). You should now see the correct aileron movement.

TEP 4: ELEVATOR CHECK



Incline the plane NOSE UP. You should see the elevator move down. And when you move the
NOSE DOWN, the elevator should move up. Move the Elevator knob to the opposite side
(from Centre) if the servo movement is incorrect:



Adjust Elevator gain according to your aircraft requirement (lowest gain nearest to centre,
highest gain further away from centre).

STEP 5: RUDDER CHECK



Rotate the plane at its centre axis from left to right. You should see the following action:



Move the Rudder knob to the opposite side (from Centre) if the servo movement is incorrect:



Adjust Rudder gain according to your aircraft requirement (lowest gain nearest to centre, highest gain
further away from centre).

STEP 6: FLIGHT TEST AND SENSITIVITY ADJUSTMENT



Steps 1 to 5 should enable you to correctly set your servo movement direction via the 3 knob dials.



To fine tune your aircraft attitude control via the FY-21AP, some flight testing has to be performed.



For the first flight it is recommended that the gains not be set too high. This will reduce large
oscillation or „flight overcorrection‟.



After the flight take off, switch the device from Mode 1 (deactivated) to Mode 2 (Stabilized mode).



If you see oscillation of the wings, this indicates the Aileron gain is set too high. Switch back to Mode
1 (deactivated) and land the airplane.



Reduce the sensitivity (move dial towards centre position) and fly again. You should see improvement
in wing attitude. Adjust until you are satisfied with the level of wing stabilization.



Too much Elevator gain will show the tail moving up and down (rocking). Too much Rudder gain will
show tail wagging. Reduce gain until this flight overcorrection is gone.



Alternately, if you find the flight correction is not enough, you can increase gain accordingly.

WARNING: SAFETY PRECAUTION – MUST READ

The purpose of the FY-21AP (AFSS) is to stabilize the aircraft. It is not an Anti-Stall device. The
stabilization action of the FY-21AP will fail if the aircraft is stalled. Please ensure adequate throttle
especially when in the Autopilot Modes.

II.

The aircraft direction is controlled by you, at all times. Make sure you know where you are going.

III.

The FY-21AP is for your enjoyment. But do not fly the plane into a crowded area, where your aircraft
can cause serious injury if it crash. Please be responsible when using this product.

IV.

Besides the regular pre-flight checks (we recommend a checklist). Always check the correct operation
of the stabilizer on the ground prior to take off.

Any electronic and hardware on an RC aircraft can fail over time. Please assess your aircraft and
electronic condition before use. FeiYu Tech is not responsible for any losses or injury as a
consequence of using this product.

VI.

Please ask an experienced RC Plane pilot for assistance if you are a beginner. It is absolutely critical
that you get flight basics before proceeding. You also need directions to correctly assemble, take off
and control your RC Model. We highly recommend joining your local RC Model club.

VII.

Never fly close to people, buildings, overhead wires, vehicles, trees or closed spaces. You could
seriously injure yourself or someone else.

VIII.

Minimum flying distance should be 20 foot from you and others. Learn about emergency procedures
should you lose control of your aircraft.

IX.

Keep the RC Model and related equipment away from children. RC planes are not toys. Children
must be supervised at all times if they are allowed to fly.

Please operate your RC plane within the permitted area of your local government. For more detail,
please check with your local council or government.

XI.

If you are not using 2.4 GHz spread spectrum radio, never turn on your radio before checking and re-
checking that you're the only one using the frequency. You could cause a crash of another aircraft if
the frequency is the same. For security; please obey to the local frequency regulation.

XII.

Never use the remote control within three miles of your local airport. You could endanger full scale
aircraft instruments. Lives could be lost.

XIII.

Keep all electrical equipment away from rain water, moisture and extreme high temperature.

XIV.

DO NOT OPEN any FY-TECH Attitude Flight Stabilization System (AFSS) unit or any of our other
modules. Opening or dismantling the module cover will null any kind of warranty we and our
distributor have on the product you purchased.

The knobs control both
gain and servo direction.
The gyro gain is lowest
when the knob in the
middle. i.e. The further
away from center, the
higher the gyro gain.
Turning the knob left or
right off-center will change
servo direction.

Rotate right

Rudder moves to the left

Rotate left

Rudder moves to the right

FY-21AP IN STABILIZED MODE