FeiYu Tech FY31AP Original operating instructions

Guilin Feiyu Electronic Technology Co., Ltd
Rm. B305, Innovation Building, Information Industry Park, Chaoyang Road, Qixing Distri t,
GuiLin, CN
www.feiyu-tech.com
Email: feiyute h@yahoo. n
FEIYU
TECH
FY31AP
Autopilot System
Installation & Operation Guide
Rev 1: 24 February 2012

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Manual Update list
Revision Date Updated
page
Topic updated
0 28 November 2011 N/A First Release of Manual
1 24 February 2012 Page 21 Error in F 31AP connection diagram
corrected.

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Table of Contents
Manual Update list ............................................................................................................................................... 1
INTRODUCTION ................................................................................................................................................... 4
GPS Home Lock, Barometric Altitude and 8 Waypoint ........................................................................... 5
Optional Upgrade with Hornet OSD and Data Radio .............................................................................. 6
F 31AP Package Content ................................................................................................................................. 7
Technical Specification and Technical requirements .................................................................................. 7
Remote control system requirement ............................................................................................................... 7
F 31AP Flight Modes ........................................................................................................................................... 8
F 31AP Autonomous Flight Modes ................................................................................................................. 8
Stall warning ......................................................................................................................................................... 9
Red LED Flashing & Gyroscope Re-set ......................................................................................................... 10
Initialization / Reset Process............................................................................................................................. 10
Flight Mode Indicator (Red or Blue light) ...................................................................................................... 11
GPS status & vibration level indicator ........................................................................................................... 12
F 31AP Interface ................................................................................................................................................. 13
Dip Switch Function ........................................................................................................................................... 19
GPS Receiver Connection .................................................................................................................................. 14
GPS – Satellite Signal Lost During Autonomous Flight ............................................................................ 15
UART Interface .................................................................................................................................................... 15
F 31AP Electrical Connection and Diagram................................................................................................ 16
Vibration damping ............................................................................................................................................. 17
SW 1 and SW 2 : Switch Settings for F 31AP ................................................................................................ 18
Connection layout of F 31AP .......................................................................................................................... 21
F 31AP installation: Orientation, Position and level ................................................................................ 22
Adjustment Dials for ELE, AIL and RUD ...................................................................................................... 23
Control Surface Movement Check ................................................................................................................. 23
Recording our Aircraft Neutral Value ....................................................................................................... 25
Recording Neutral Value ‘On the Fly’ .......................................................................................................... 27
First Flight Test And Sensitivity Adjustment................................................................................................ 28
Gyroscope initialization (re-setting): ............................................................................................................. 28

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Dear Pilot,
Thank you for choosing F 31AP as your autopilot system. Please read this manual carefully
before using the system to ensure proper use and operation.
The installation and use of this device require some skill and knowledge in flying remote
controlled fixed wing aircraft.
• If you are a complete beginner and have never flown one before, we do not
recommend you install this device on your own.
• Please find assistance from an experience RC Pilot who may provide you with the
basic knowledge required to use this device successfully.
• If you are already an experienced flyer, you will find the F 31AP installation to be
easy and logical. Just follow this manual and you won’t go wrong.

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INTR DUCTI N
Attitude Flight Stabilization System (AFSS)
F 31AP is an inertial attitude measurement instrument used for automated stabilization of
fixed wing model aircrafts and two axis camera gimbals.
F 31AP has an integrated three-axis gyro and three-axis accelerometer which controls the
aircraft movement in three-dimensional space. By using your remote control, the unit can be
turned on or off for the following functions:
v Level flight – When stabilization is activated, the F 31AP will automatically control
the aircraft for smooth easy flying. For beginners in RC aircraft flying, this is advantages
as it makes flight easier and increases the student pilot self-confidence. The system can
be activated throughout the entire flight duration, from take off to landing.
v Emergency Recovery - If you lose orientation release all control sticks, maintain
throttle and switch ON the F 31AP. The unit will automatically send the correct signals
to balance of the aircraft and regain level flight, giving you time to get your
orientation and fly the plane back to safety.
v Autonomous flight – with the GPS Receiver connected, the F 31AP will enable you
to fly fully autonomous, with up to 8 waypoint settings using the F Ground Control
Station (GCS) software.
v Ground Control Station – the F GCS software will enable you to fly autonomously
to up to 8 waypoints, display in-flight telemetry data, and record that flight for replay
and analysis (this requires the optional Data Radio hardware).
v Return to Home – ou can set autonomous return to home via a 3 way switch or
through your failsafe setting, enabling you plane returning to home should it lose your
transmitter signal. Upon reaching the home point it will automatically engage auto
circling, while it waits for your further instructions.
v Automated circling - by activating this function, the aircraft will automatically circle
the selected area at a fixed altitude. ou can set the circling radius.
v First Person View - for long-distance RC flight via video transmitter, the F 31AP will
maintain the balance of your aircraft. ou only need to control the heading of your
aircraft and enjoy the view.
v Firmware upgrade – The F 31AP firmware is upgradable by connecting to your

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computer via a USB TTL cable. As Feiyu Tech continuously improves the F 31AP
system, firmware upgrades will be released periodically.
GPS Home Lock, Barometric Altitude and 8 Waypoint
a) F 31AP control module incorporates an accurate barometric pressure sensor. At start
up, when five (5) or more GPS satellites are detected, the F 31AP will note this as the
Home position.
b) The barometric air pressure and GPS data is merged to provide accurate relative
altitude measurement.
c) The GPS data enables the F 31AP to fly to 8 Waypoints via the F -GCS programme and
Data Radio.
d) Note that if the F 31AP is not connected to the GPS receiver, autonomous flight cannot
be engaged and it will function purely as a flight stabilizer.

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ptional Upgrades
a) The F 31AP is a standalone system that can function as an autopilot on its own.
b) However, adding the following optional upgrades allows you to expand the autopilot
capabilities of the system.
• Hornet SD – Allows you to display the autopilot
telemetry data onto your downlinked video display.
Refer the Hornet OSD Manual.
• Ground Control Software – ou can download and use the software for free.
Refer the F 31AP GCS
Manual to
understand the GCS
functions.
• Data Radio – ou can fly via the GCS and 8 waypoint settable.
• FY3ZT Remote Adapter – allows you to fly the
aircraft with only the F 31AP and Data Radio on
board. A simple way to increase your flight range
when using 433 mHz data radio.

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FY31AP Package Content
• F 31AP control module *1;
• RC receiver connecting wires * 1;
• GPS receiver module * 1;
• Velcro double sided tape * 2;
• Instruction manual * 1;
• Some related wires.
Technical Specification and Technical requirements
• FY31AP module:
Input voltage: 4.0 ~ 6.0 Volt;
Current draw: 50mA (5V);
Size: 55 x 33 x 20 mm;
Weight (excluding wires): 20g;
Temperature range: -25 ° C ~ +70 ° C;
Maximum rate of rotation : ≤ 2000 degrees
• GPS Receiver Module:
Input voltage: 3.0 ~ 3.3 Volt;
Current draw: 60mA (3.3V);
Size: 25 x 25x 15 mm;
Weight (excluding wires): 20g;
Temperature range: -25 ° C ~ +70 ° C;
• Application
The F 31AP can be installed in the following aircraft :
1. Normal / Traditional fixed-wing planes
2. Delta-winged plane with rudder
3. Delta-winged plane without rudder
4. Plane without aileron
5. V-tail plane with and without ailerons
6. Any other configuration , please e-mail us for enquiry: servi[email protected]
Remote control system requirement
The F 31AP has been tested to work with the following RC systems:
• Robbe-Futaba PPM / PCM 1024 / PCM G3 mode, 2.4 GHz systems

• Graupner/JR PPM 8, PPM 12, SPCM mode

• MPX PPM8, PPM 12 with UNI mode
• Any remote control system using the standard of 1.5 ms neutral position.

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FY31AP Flight Modes (SW 1)
a) The F 31AP has three flight modes controlled by SW-1.
b) ou can activate any of the flight modes via a free Receiver channel and a 3-position
switch on your computer radio connected to the SW 1 interface on the F 31AP.
c) Mode 1: Deactivated Mode. In this mode, all control of the aircraft is by the pilot. The
F 31AP does not participate in flight control.
d) Mode 2: Stabilized mode
. In this mode and your transmitter control sticks at center,
the F 31AP will continuously send out controlling signal (aileron, elevator, rudder) to
ensure the aircraft maintains a stabilized, horizontal flight and constant flight direction.
In this mode F 31AP will not allow acrobatic flights.
e) Model 3: Airline flight mode, in this mode, the waypoint will be set according to the
flight path to automatic flight.
FY31AP Autonomous Flight Modes (SW 2)
a) Three autopilot modes are incorporated into the F 31AP controlled by SW 2.
b) ou may set the modes via a free receiver channel and a 3-position switch.
c) Autopilot mode 1:
Deactivated. The autopilot function is not activated.
d) Autopilot mode 2: Auto Return To Launch

RCL

. When activated in this mode, the
F 31AP will automatically fly the plane back to the take-off point, while maintaining
altitude. Upon reaching the launch area, the unit will automatically fly the plane in a circle
at a default circling radius of 120 meters.
e) Autopilot mode 3: Auto Circling Mode (ACM). When activated in this mode, the
plane will immediately fly in a circle.
The centre of the circle is the point of activation. The
default circle radius is 120 meters. The aircraft altitude will be automatically maintained
throughout the ACM.

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STALL WARNING
a. On its own, the F 31AP has no control over the throttle channel. Therefore, if your
aircraft forward movement cannot compensate for the autopilot’s active altitude hold
in RTH and Auto Circling, your aircraft will stall.
b. This is especially important if RTL is part of your RC failsafe. In the event of RC Link lost,
you may set RTL into your Receiver failsafe. However, DO NOT forget to also set your
throttle failsafe to between 25 % to 50% to ensure the plane does not stall.
c. Never set your throttle failsafe to zero. If you do so, your aircraft will RTL in a
continuous stalled flight which will result in a crash.
d. When flying under autonomous GCS control, F 31P will control the throttle level
based on the target speed (refer GCS Manual). However, the throttle level on your
radio transmitter has priority over the GCS Autonomous control. Please ensure that
your throttle level is high enough to maintain the target speed and altitude hold.
Failing which, your aircraft may stall.

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Red LED Flashing & Gyroscope Re-set
If the following conditions occur, the F 31AP Gyro initialization is recommended:
(a) The device has not been used for a long time.
(b) There is a change in environmental temperature of over 30 degrees since last flight.
(c) The Red LED flashes continuously, even when the F 31AP remains stationary.
(d) If the Red LED light is on solid all the time even when the F 31AP is stationary, it means
the gyroscope is faulty and that the unit needs to be sent back for repair.
Gyroscope Reset Procedure:
1. Carry out this re-setting procedure only if the above occur. We do not recommend
regular re-setting. It is not necessary and not recommended.
2. The stabilizer unit does not need to be in a horizontal position during initialization.
However, you must ensure there is no vibration during this process. If you suspect
shaking occurred, just restart the initialization / resetting process.
Initialization / Reset Process
a) Install the jumper as shown in this picture:
b) Power-ON the F 31AP and keep it stationary for at least 20 seconds. ou will notice the
red light blink with two different rates.
c) After 20 seconds, the re-setting / initialization is complete.
d) Disconnect the power, unplug the jumper & remove it (keep safe for future use).

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Flight Mode Indicator (Blue LED light)
By observing the flight indicator, you can easily re-confirm your Flight Mode switch settings of
your radio.
Flight Mode Indicator:
Autopilot Indicator:

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GPS status & vibration level indicator
ou can check the GPS lock status and vibration level by observing the Red LED.
Red LED light:
Status Too much
vibration No GPS Need to initialize
Gyro
GPS location fixed
(4 satellites)
Red LED
Flashing Stay on solid Stay off solid
Continuous
flashing
Continuous double
flash each loop

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FY31AP Interface
Pin Interface:
Elevator
sensitivity
knob
Rudder sensitivity
knob
Blue LED: Flight
mode & Autopilot
indicator.
Red LED: GPS
status &
vibration level
indicator
Interface pin
panel
Function DIP
Aileron
sensitivity knob

2
3
4
5
6
7
8
III
IV
II
I
1
Jumper installed
during gyro
initialization.
Do not insert jumper
during normal use.
ARR W F RWARD
(T WARDS FLIGHT
DIRECTI N)
N TE: The pin “I-1,2,3,4” is for the GPS module. Pin “I-3” outputs +3.3V of power,
D N T SUPPLY External Power to this pin, you will burn the F -31AP board.

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GPS Receiver Connection (Pin Interface “I-1, I-2, I-3, I-4”)
The F 31AP GPS pin consists of this interface: GND, 3.3V voltage, TX0, TX0. The parameters
are:
• Data bits: 38400
• Interface Features: TTL level
• Data bits: 8
• Stop Bits: 1
• Parity: None
Connect the above pins to the GPS Receiver.
Data Protocol
The GPS data protocol is a standard NEMA0183 and the statement must be $ GPRMC, $
GPGGA.
N TE: The pin “I-1,2,3,4” of the F 31AP pin interface is for the GPS module power
supply. i.e. The F 31AP pin “I-3” outputs +3.3V of power via this pin.
D N T SUPPLY External Power to this pin, or you will burn the F -31AP board.
GPS Related Functions
a. If GPS cannot fix the aircraft location (minimum 5 satellites), only Mode 1
(Deactivated) and Mode 2 (Stabilized Mode) will function. Mode 3 and Autopilot
will not be functional.
GPS Receiver pin
connection

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b. Install the GPS Module with the antenna face up (see above). DO NOT install next to
metal or carbon fiber and other shielding material, which may block satellite signal.
c. Install the GPS Module away from electromagnetic sources such as ESC’s, power wires,
servo wires and video transmitters.
GPS – Satellite Signal Lost During Autonomous Flight
• GPS provides the aircraft geographic positioning, altitude, speed and flight direction.
• Only if the GPS Data is available will the F 31AP perform its Autopilot Modes.
• In case GPS signal is lost during autopilot flight, the F 31AP will keep its height and
maintain its last flight direction. After GPS signal is regained, the plane will resume its Autopilot
Mode
UART Interface(Position is “II-1, II-2, II-3, II-4”)
The UART pin interfaces consist of: GND, power, TX1, RX1. The characteristics are as follow:
• Baud Rate: 19200
• Data bits: 8
• Stop Bits: 1
• Parity: None
• Interface features: TTL
The pin interfaces output telemetry data. This interface connects to the data radio, PC
computer serial port or OSD module. ou can set the flight route, navigation and control
parameters of F 31AP by this interface. The port is also used to upgrade F 31AP firmware.
Please read the procedure for the firmware upgrading.
UART Interface

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FY31AP Electrical Connection and Diagram
a) Power supply
• The F 31AP operates between 5 to 6 volts input.
• F 31AP is powered via the Receiver connection (Channel 1).
• If your plane is Electric powered, the Receiver power may be supplied via
the ESC built-in Battery Elimination Circuit (BEC). However, we highly
recommend that a separate BEC with a 3A output.
• For Gas or Nitro powered planes, you will require a battery to power the
Receiver and F 31AP.
b) The F 31AP is connected to your RC Receiver
via a 6 wire cable. ou need a minimum 6
Channel RC Receiver.
c) Note that the wire is arranged according to color :
Wire color Receive channel
White
(bundled with red & black) aileron Channel 1
orange elevator Channel 2
green throttle Channel 3
yellow rudder Channel 4
brown SW 1 - Any free channel controlled by
3-way switch or dial knob Channel 5
blue SW 2 - Any free channel controlled by
3-way switch or dial knob Channel 6
d) Note that you need 2 free Receiver channels to control the F 31AP Flight Modes and
Autopilot Mode, using either a 3-position switch or your dial knobs.
1
2
3

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Vibration damping
a) The F 31AP flight controller algorithms can work under normal vibration levels. However if
the vibration and shock experienced by the sensors are excessive, stabilization can fail of
the system can shut down altogether.
b) To achieve the best stabilization and flight performance, minimize the amount of vibration
on the aircraft as best you can.
c) Examples of vibration reduction steps that can be taken:
i) Ensure your motors are mounted properly and squarely.
ii) Balance your propellers regardless of the manufacturer’s claim of perfect balance out
of the box.
iii) Balance your motor bell housing (if possible).
iv) Ensure rigidity of your frame (no flexing with motor rotation).
v) Use appropriate propeller length and pitch for the size of your aircraft.
d) The F 31AP is supplied with the double-sided foam padding dampers. Please use them as
shown below:
Checking for Vibration Levels
To confirm correct vibration damping, please follow this procedure:
a) After connecting all wires between to the F 31AP, including RC Receiver and ESC, install
the unit on your plane (ensure correct orientation).
b) Run the plane engine or motor at different throttle levels. DO NOT TAKE OFF.
c) At each throttle position, observe the state of the red LED light. If it stays OFF, that
means your vibration level is acceptable.
d) If instead the red LED lights up and stays ON solid, then the vibration dampening is not
enough. ou will need reduce the level of vibration on your aircraft. Refer above
suggestions on vibration reduction.

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SW 1 and SW 2 : Switch Settings for FY31AP
a. SW-1 Flight Modes
The F 31AP has 3 Flight modes controlled via SW-1. To select the
modes, use a free Receiver channel controlled via a 3 way-switch:
FY31AP FLIGHT M DES
SW-1 signal
output 900-1200us 1200-1800us 1800-2100us
Functional mode Stabilization
deactivated
Auto
Stabilization Mode
Auto
Navigation Mode
Blue LED light
indicator
Continuous
flashing Stay on solid Single Flash
b. SW-2 Autopilot Modes
F 31AP Autopilot Modes is controlled via SW-2.
IMP RTANT: The Autopilot Mode (SW-2) has controlling priority over the Flight Modes
(SW-1). If you wish to use the Flight Mode (SW-1), you must de-activate the Autopilot first.
SW-2 signal
output 900-1200us 1200-1800us 1800-2100us
Functional mode Return To Home
(RTH)
Autopilot
Deactivated Auto Circling (ACM)
Blue LED light
indicator
Continuous Double
flash each loop
Flashing depends on
SW 1 Signal
Continuous flashing 3
times each loop
900-1200us Dea tivated mode
1200-1800us Auto Stabilization Mode
1800-2100us Auto Navigation Mode
900-1200us Return To Laun h Mode
1200-1800us Can el Mode
1800-2100us Auto Cir ling Mode

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Dip Switch Function
AIRCRAFT DIP SWITCH SETTING
1) F 31AP connection for traditional aircraft layout:
AIL OUT ELE OUT THR OUT RUD OUT
Aileron Servo Elevator
Servo Throttle Servo Rudder
Servo
2) F 31AP connection for flying wing aircraft: (with or without Rudder)
AIL OUT ELE OUT THR OUT RUD OUT
Differential
Servo 1
Differential
Servo 2
Throttle
Servo Rudder Servo
3) F 31AP connection for V tail aircraft with Aileron:
AIL OUT ELE OUT THR OUT RUD OUT
Aileron
Servo
Differential
Servo 1
Throttle
Servo
Differential
Servo 2
4) F 31AP connection for V tail aircraft without ailerons:
AIL OUT ELE OUT THR OUT RUD OUT
Differential
Servo 1
Differential
Servo 2 Throttle servo
Null
Note: In this manual, the switch
direction is shown by white color.