Fig. 10 · VTOL · ArduPlane V4.7.2

VTOL tiltrotor

Fly it

Parts: …
Battery: unplugged
Fault: none

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Pick the battery, motors and props. Every number below is recalculated from this craft's own model.

Battery

Motors

Props

Calculated for this build

All-up weight: 1,585 g
Thrust : weight: 2.8 : 1
Hover throttle: 60%
Max current: 116 A
Hover time: 25.1 min
Cruise time: 75.9 min
Cruise speed: 47 km/h

Checks

Parts match: 2.8:1 thrust to weight for take-off and landing, about 15 A in hover and about 5 A in cruise, once the wing carries the weight. The hover time assumes it never leaves hover; the cruise time is what the wing gives. A real mission hovers only a minute or two at each end.

No problems found with this combination.

Cost

Category	Parts	Cost
Electrical	8	$445
Mechanical	5	$224
Total (approx.)	13	$669

Every connection on the craft. Choose one to select both ends on the figure, or open the hand-inked wiring sheet.

power
motor phases
data / signal
video

power:XT60 · 4S2P Li-ion, 14.8 V
The pack's XT60 mates with the craft's. It is keyed, so it only goes in one way, and the pack carries the female plug, so a loose pack can't short.
power:VBAT · 3 ESC leads · 1000 µF 35 V on the FC battery pads
The flight controller's battery pads feed the three ESC leads: two out under the wing to the nacelles, one back along the boom. The capacitor sits across the same pads.
motor phases:3-phase A/B/C × 3 · slack loop across each tilt pivot
Three phase wires per motor, in a slack loop across each tilt pivot. Their order is not a safety matter: swapping any two reverses the motor.
data / signal:DShot600 · S3 Motor1 front right, S4 Motor2 front left, S5 Motor4 rear
DShot600 on S3, S4 and S5, an output group that runs nothing but DShot: Motor1 front right, Motor2 front left, Motor4 on the boom.
data / signal:S1 TiltMotorFrontLeft (75), S2 TiltMotorFrontRight (76) · PWM · servo BEC
The tilt servos on S1 and S2, powered from the board's 8 A servo BEC. They have an output group of their own, so they can run at a servo rate while S3 to S6 run DShot.
data / signal:S7 VTailLeft (79), S8 VTailRight (80) · PWM
The two ruddervator servos on S7 and S8; ArduPilot mixes pitch and yaw into them.
data / signal:S9, S10 Aileron (4) · PWM
The two aileron servos on S9 and S10, both set to Aileron (function 4). Reverse one if it moves the wrong way.
data / signal:USART2 = SERIAL3 · GPS · compass on I2C
The GPS on USART2, the board's GPS port, and its compass on the I2C bus.
data / signal:I2C · MS4525DO (ARSPD_TYPE 1)
The 4525 airspeed board on I2C (ARSPD_TYPE 1). The pitot's two tubes go to its two ports: swapped, it reads 0 or less.
video:C1 camera in · VTX out with OSD · SmartAudio on UART4 TX
Camera video into the board, which lays the OSD over it, and out to the VTX on the rear deck, powered from the 9/12 V BEC. SmartAudio on UART4 TX lets the OSD change channel and power.

A working emulation of the ArduPilot Plane command line for this craft: real setting names, real limits and real error messages.

Connect tcp:127.0.0.1:5760 source_system=255

Up and down recall earlier commands.

Configuration snippets

QuadPlane and tilt-rotor after the build

Q_ENABLE makes ArduPlane a QuadPlane, Q_FRAME_CLASS 7 makes its lift motors a tri and Q_TILT_ENABLE adds the tilt-rotor code. Reboot after those three, or pre-arm says "tiltrotor setup not complete, reboot". Q_TILT_TYPE 2, vectored yaw, is what lets this tri yaw without a tail servo. Mind the rate names, they are easy to swap: RATE_DN is hover to forward, RATE_UP forward back to hover.

# ArduPlane 4.7.2 on a Matek H743-WING: a tri QuadPlane whose front rotors tilt
param set Q_ENABLE 1            # QuadPlane on
param set Q_FRAME_CLASS 7       # Tri: motors 1, 2 and 4 (Q_FRAME_TYPE is ignored)
param set Q_TILT_ENABLE 1       # tiltrotor support
# reboot (MAVProxy: reboot), then:
param set Q_TILT_MASK 3         # motors 1 and 2 tilt (bit 0 + bit 1); motor 4 stays upright
param set Q_TILT_TYPE 2         # VectoredYaw: the front pair tilt opposite ways to yaw in hover
param set Q_TILT_YAW_ANGLE 10   # deg the servos may go back past vertical for that
param set Q_TILT_MAX 45         # deg the rotors hold while the airspeed builds
param set Q_TILT_RATE_DN 15     # deg/s from hover towards forward flight
param set Q_TILT_RATE_UP 25     # deg/s from forward flight back to hover

Outputs after the build

The H743-WING groups its outputs, and every output in a group runs at the same rate: the tilt servos on S1 and S2, the three lift motors on S3 to S5 with DShot600, the ruddervators and ailerons on S7 to S10. ArduPilot's tri uses motors 1, 2 and 4. Set the reversal on the bench, so MANUAL points the rotors forward and QSTABILIZE straight up.

# H743-WING output groups: S1-S2, S3-S6, S7-S10 (a group shares one rate, so DShot gets S3-S6 to itself)
param set SERVO1_FUNCTION 75    # TiltMotorFrontLeft
param set SERVO2_FUNCTION 76    # TiltMotorFrontRight
param set SERVO3_FUNCTION 33    # Motor1, front right
param set SERVO4_FUNCTION 34    # Motor2, front left
param set SERVO5_FUNCTION 36    # Motor4, rear (a tri has no motor 3)
param set SERVO7_FUNCTION 79    # VTailLeft
param set SERVO8_FUNCTION 80    # VTailRight
param set SERVO9_FUNCTION 4     # Aileron
param set SERVO10_FUNCTION 4    # Aileron
param set Q_M_PWM_TYPE 6        # DShot600 for the three lift motors
# MANUAL must point the rotors forward and QSTABILIZE straight up. The two servos face each other,
# so one is reversed; if MANUAL tilts a rotor back, flip that servo's setting:
param set SERVO1_REVERSED 0
param set SERVO2_REVERSED 1

Board, radio, GPS and airspeed after the build

Arrow to the nose; ELRS on a full UART with CRSF at 420 kbaud; the GPS on USART2; the 4525 airspeed board on I2C, flown on; and the board's own current sensor, with the scale Matek gives for the WING V3.

# The board, the receiver, the GPS, the airspeed sensor and the battery monitor
param set AHRS_ORIENTATION 0    # FC arrow to the nose; 4 = Yaw180 if it points back
param set SERIAL2_PROTOCOL 23   # RCIN: ELRS (CRSF) on USART1
param set RSSI_TYPE 3           # link quality from the receiver protocol
param set RC_OPTIONS 8192       # bit 13: 420 kbaud for ELRS
param set SERIAL3_PROTOCOL 5    # GPS on USART2
param set GPS1_TYPE 1           # auto-detect
param set ARSPD_TYPE 1          # MS4525DO on I2C
param set ARSPD_USE 1           # fly on it
param set BATT_MONITOR 4        # the board's own voltage and current sensor
param set BATT_VOLT_PIN 10
param set BATT_CURR_PIN 11
param set BATT_VOLT_MULT 10.5
param set BATT_AMP_PERVLT 66.7

Airspeeds and the transition after the build

All in m/s since 4.5. AIRSPEED_MIN sits about 20 % above the stall, and Q_ASSIST_SPEED 3 m/s below that, so the rotors catch a slow turn before it stalls; at 0 it refuses to arm. If a transition hasn't reached AIRSPEED_MIN after 15 s, it is called off and the craft comes home in QRTL.

# Airspeeds in m/s (4.5 renamed ARSPD_FBW_MIN and TRIM_ARSPD_CM, which was in cm/s)
param set AIRSPEED_MIN 12       # about 1.2 x the 10 m/s stall
param set AIRSPEED_CRUISE 14
param set AIRSPEED_MAX 20
param set Q_ASSIST_SPEED 9      # below 9 m/s the lift motors help the wing; 0 refuses to arm
param set Q_TRANSITION_MS 5000  # blend from rotors to wing once AIRSPEED_MIN is reached
param set Q_TRANS_FAIL 15       # s: no AIRSPEED_MIN by then and the transition is called off
param set Q_TRANS_FAIL_ACT 1    # ... into QRTL (0 = QLAND)

Failsafes after the build

A link lost for 5 s in a plane mode means RTL, which turns into a vertical landing near home; in the Q modes a lost link means QLAND at once. Two battery steps: RTL at 3.3 V per cell and QLAND at 3.1 V. Li-ion runs lower than LiPo, so these sit lower than on a LiPo craft.

# Radio lost, battery low, battery critical
param set THR_FAILSAFE 1
param set THR_FS_VALUE 950      # throttle PWM below this counts as lost
param set FS_SHORT_ACTN 0       # short loss: carry on (circle in the plane modes)
param set FS_LONG_ACTN 1        # 5 s: RTL, which turns into QRTL near home
param set FS_LONG_TIMEOUT 5
param set BATT_CAPACITY 8000    # mAh
param set BATT_LOW_VOLT 13.2    # 3.3 V per Li-ion cell under load
param set BATT_CRT_VOLT 12.4    # 3.1 V per cell
param set BATT_FS_LOW_ACT 1     # low: RTL
param set BATT_FS_CRT_ACT 4     # critical: QLAND where it is

OSD and VTX after the build

The built-in OSD lays the battery, the airspeed and the mode over the camera's picture. The VTX starts at 25 mW on the bench; raise VTX_POWER only where the law allows it.

# The board's own analog OSD, and the VTX on SmartAudio
param set OSD_TYPE 1            # the built-in AT7456E
param set OSD1_ASPEED_EN 1      # airspeed on the screen
param set VTX_ENABLE 1
param set SERIAL6_PROTOCOL 37   # SmartAudio on UART4 TX
param set VTX_BAND 4            # RaceBand
param set VTX_CHANNEL 0         # R1
param set VTX_POWER 25          # mW on the bench
param set VTX_MAX_POWER 800

QHOVER for QHOVER

Hover with height hold: centre the throttle and it keeps its height, the right stick tilts it up to 30°. It drifts with the wind. Every flight starts and ends here.

# QHOVER: a multicopter with height hold; the throttle stick asks for a climb or a sink
param set Q_A_ANGLE_MAX 30      # max lean in the Q modes, deg (4.7 renamed Q_ANGLE_MAX, which was in cdeg)
mode QHOVER

QLOITER for QLOITER

QHOVER plus GPS position hold: let go of the sticks and it stops where it is. Use it for the first hovers and to line up a landing.

# QLOITER: the GPS holds the position too; centre the sticks and it stops where it is
mode QLOITER

The transition: FBWA for FBWA (transition)

Switch from a Q mode to FBWA and the transition starts: the rotors tilt to 45° and it speeds up on them; past AIRSPEED_MIN the wing takes the weight, the rotors finish tilting and the rear motor stops. Then the sticks bank and pitch the plane, up to 45° and 20°, and the throttle sets the speed. Switch to a Q mode to hover again.

# Forward transition: switch from a Q mode to FBWA (or CRUISE, LOITER, AUTO). The rotors tilt to
# Q_TILT_MAX and hold height until AIRSPEED_MIN, the lift fades out over Q_TRANSITION_MS, and the rotors
# finish tilting at 90 deg/s. The rear motor stops. Then the sticks fly the wing:
param set ROLL_LIMIT_DEG 45     # max bank
param set PTCH_LIM_MAX_DEG 20   # max nose up
mode FBWA
# Back to hover: any Q mode. The rotors swing up at Q_TILT_RATE_UP while it slows down

QRTL for QRTL

QRTL flies home at Q_RTL_ALT and lands vertically. With Q_RTL_MODE 1 a plain RTL flies home as a plane and turns into QRTL near home. RTL_AUTOLAND must stay 0 with that, or the board refuses to arm.

# Come home and land: QRTL climbs or sinks to Q_RTL_ALT, flies home and lands vertically
param set Q_RTL_MODE 1          # RTL flies home as a plane and turns into QRTL near home
param set RTL_AUTOLAND 0        # must stay 0 with Q_RTL_MODE set, or it refuses to arm
param set Q_RTL_ALT 15          # m
param set Q_LAND_FINAL_ALT 6    # m: the slow part of the landing starts here
param set Q_LAND_FINAL_SPD 0.5  # m/s (was Q_LAND_SPEED, in cm/s)
mode QRTL

AUTO: the coast survey for AUTO (coast survey)

AUTO flies the uploaded mission: a vertical take-off, the three photo points and a vertical landing on the village pad. A DO_VTOL_TRANSITION 3 after the take-off keeps the photo legs in VTOL flight so it can stop over each point; without it Plane would transition and fly the waypoints on the wing. Arm in a Q mode, then switch to AUTO.

# The coast survey: VTOL_TAKEOFF to 12 m, DO_VTOL_TRANSITION 3 so the photo legs are flown as a VTOL
# (without it Plane flies the waypoints on the wing, and a wing cannot stop over a point), photos at the
# lighthouse, the buoy and the mast, VTOL_LAND on the village pad (MAVProxy wp module; Mission Planner:
# Plan > Load WP File)
# wp load survey.txt
mode QHOVER
arm throttle
mode AUTO

Meet the VTOL

A VTOL (vertical take-off and landing) plane takes off and lands like a multicopter and flies like an aeroplane. This one is a tilt-tricopter QuadPlane: two front motors sit on nacelles that tilt from straight up, for hover, to straight forward, for cruise, and a third motor on the tail boom only lifts. Once the wing carries the weight the motors only push against drag, so it cruises on about 5 A where hover takes 15: over an hour in the air instead of 20 minutes. The hard part is the transition, the few seconds when the wing is still too slow to lift and the rotors already point partly forward. ArduPlane 4.7.2 handles it: it tilts the rotors to 45°, holds the height on them until the airspeed sensor reads 12 m/s, then hands over to the wing. This is a 1.2 m foam airframe on a Matek H743-WING with GPS, an airspeed sensor and analog FPV, about 1.6 kg with an 8000 mAh Li-ion pack. Craft like it map fields and inspect coasts and power lines from places with no runway. Pick the parts and watch the numbers, build it, run the bench checks, then fly the coast.

Practice task

Start in QHOVER and QLOITER: take off, hover, land on the pad. Then, high and well clear of everything, switch to FBWA with the throttle up and watch the airspeed climb past 12 m/s as the rotors tilt and the wing takes over; switch back to QHOVER to slow down and hover again. Fly the coast run that way, and let AUTO fly the survey. On a real build: a smoke stopper on the first plug, the tilt servo test and the motor direction check with the props off, accelerometer and compass calibration, the airspeed check, and every pre-arm message read. Make the first transition at 30 m or more, into wind, with a thumb on the switch back to QHOVER.

Build it, test the tilt servos, then fly the coast and hand over to the wing

Category

Parts

Cost

Electrical

$445

Mechanical

$224

Total (approx.)

$669

# ArduPlane 4.7.2 on a Matek H743-WING: a tri QuadPlane whose front rotors tilt param set Q_ENABLE 1 # QuadPlane on param set Q_FRAME_CLASS 7 # Tri: motors 1, 2 and 4 (Q_FRAME_TYPE is ignored) param set Q_TILT_ENABLE 1 # tiltrotor support # reboot (MAVProxy: reboot), then: param set Q_TILT_MASK 3 # motors 1 and 2 tilt (bit 0 + bit 1); motor 4 stays upright param set Q_TILT_TYPE 2 # VectoredYaw: the front pair tilt opposite ways to yaw in hover param set Q_TILT_YAW_ANGLE 10 # deg the servos may go back past vertical for that param set Q_TILT_MAX 45 # deg the rotors hold while the airspeed builds param set Q_TILT_RATE_DN 15 # deg/s from hover towards forward flight param set Q_TILT_RATE_UP 25 # deg/s from forward flight back to hover

# H743-WING output groups: S1-S2, S3-S6, S7-S10 (a group shares one rate, so DShot gets S3-S6 to itself) param set SERVO1_FUNCTION 75 # TiltMotorFrontLeft param set SERVO2_FUNCTION 76 # TiltMotorFrontRight param set SERVO3_FUNCTION 33 # Motor1, front right param set SERVO4_FUNCTION 34 # Motor2, front left param set SERVO5_FUNCTION 36 # Motor4, rear (a tri has no motor 3) param set SERVO7_FUNCTION 79 # VTailLeft param set SERVO8_FUNCTION 80 # VTailRight param set SERVO9_FUNCTION 4 # Aileron param set SERVO10_FUNCTION 4 # Aileron param set Q_M_PWM_TYPE 6 # DShot600 for the three lift motors # MANUAL must point the rotors forward and QSTABILIZE straight up. The two servos face each other, # so one is reversed; if MANUAL tilts a rotor back, flip that servo's setting: param set SERVO1_REVERSED 0 param set SERVO2_REVERSED 1

# The board, the receiver, the GPS, the airspeed sensor and the battery monitor param set AHRS_ORIENTATION 0 # FC arrow to the nose; 4 = Yaw180 if it points back param set SERIAL2_PROTOCOL 23 # RCIN: ELRS (CRSF) on USART1 param set RSSI_TYPE 3 # link quality from the receiver protocol param set RC_OPTIONS 8192 # bit 13: 420 kbaud for ELRS param set SERIAL3_PROTOCOL 5 # GPS on USART2 param set GPS1_TYPE 1 # auto-detect param set ARSPD_TYPE 1 # MS4525DO on I2C param set ARSPD_USE 1 # fly on it param set BATT_MONITOR 4 # the board's own voltage and current sensor param set BATT_VOLT_PIN 10 param set BATT_CURR_PIN 11 param set BATT_VOLT_MULT 10.5 param set BATT_AMP_PERVLT 66.7

# Airspeeds in m/s (4.5 renamed ARSPD_FBW_MIN and TRIM_ARSPD_CM, which was in cm/s) param set AIRSPEED_MIN 12 # about 1.2 x the 10 m/s stall param set AIRSPEED_CRUISE 14 param set AIRSPEED_MAX 20 param set Q_ASSIST_SPEED 9 # below 9 m/s the lift motors help the wing; 0 refuses to arm param set Q_TRANSITION_MS 5000 # blend from rotors to wing once AIRSPEED_MIN is reached param set Q_TRANS_FAIL 15 # s: no AIRSPEED_MIN by then and the transition is called off param set Q_TRANS_FAIL_ACT 1 # ... into QRTL (0 = QLAND)

# Radio lost, battery low, battery critical param set THR_FAILSAFE 1 param set THR_FS_VALUE 950 # throttle PWM below this counts as lost param set FS_SHORT_ACTN 0 # short loss: carry on (circle in the plane modes) param set FS_LONG_ACTN 1 # 5 s: RTL, which turns into QRTL near home param set FS_LONG_TIMEOUT 5 param set BATT_CAPACITY 8000 # mAh param set BATT_LOW_VOLT 13.2 # 3.3 V per Li-ion cell under load param set BATT_CRT_VOLT 12.4 # 3.1 V per cell param set BATT_FS_LOW_ACT 1 # low: RTL param set BATT_FS_CRT_ACT 4 # critical: QLAND where it is

# The board's own analog OSD, and the VTX on SmartAudio param set OSD_TYPE 1 # the built-in AT7456E param set OSD1_ASPEED_EN 1 # airspeed on the screen param set VTX_ENABLE 1 param set SERIAL6_PROTOCOL 37 # SmartAudio on UART4 TX param set VTX_BAND 4 # RaceBand param set VTX_CHANNEL 0 # R1 param set VTX_POWER 25 # mW on the bench param set VTX_MAX_POWER 800

# QHOVER: a multicopter with height hold; the throttle stick asks for a climb or a sink param set Q_A_ANGLE_MAX 30 # max lean in the Q modes, deg (4.7 renamed Q_ANGLE_MAX, which was in cdeg) mode QHOVER

# Forward transition: switch from a Q mode to FBWA (or CRUISE, LOITER, AUTO). The rotors tilt to # Q_TILT_MAX and hold height until AIRSPEED_MIN, the lift fades out over Q_TRANSITION_MS, and the rotors # finish tilting at 90 deg/s. The rear motor stops. Then the sticks fly the wing: param set ROLL_LIMIT_DEG 45 # max bank param set PTCH_LIM_MAX_DEG 20 # max nose up mode FBWA # Back to hover: any Q mode. The rotors swing up at Q_TILT_RATE_UP while it slows down

# Come home and land: QRTL climbs or sinks to Q_RTL_ALT, flies home and lands vertically param set Q_RTL_MODE 1 # RTL flies home as a plane and turns into QRTL near home param set RTL_AUTOLAND 0 # must stay 0 with Q_RTL_MODE set, or it refuses to arm param set Q_RTL_ALT 15 # m param set Q_LAND_FINAL_ALT 6 # m: the slow part of the landing starts here param set Q_LAND_FINAL_SPD 0.5 # m/s (was Q_LAND_SPEED, in cm/s) mode QRTL

# The coast survey: VTOL_TAKEOFF to 12 m, DO_VTOL_TRANSITION 3 so the photo legs are flown as a VTOL # (without it Plane flies the waypoints on the wing, and a wing cannot stop over a point), photos at the # lighthouse, the buoy and the mast, VTOL_LAND on the village pad (MAVProxy wp module; Mission Planner: # Plan > Load WP File) # wp load survey.txt mode QHOVER arm throttle mode AUTO

Meet the VTOL

Practice task

Build it, test the tilt servos, then fly the coast and hand over to the wing

VTOL tiltrotor

Design it

Calculated for this build

Checks

Cost

Build it

Try a real mistake

Selected part

Parts in the box

Wiring

Safety tests

Smoke stopper test

Motor direction check (props off)

Accelerometer calibration

Tilt servo test (props off)

Airspeed check

Pre-arm checks (props off)

MAVProxy console

Configuration snippets

QuadPlane and tilt-rotor after the build

Outputs after the build

Board, radio, GPS and airspeed after the build

Airspeeds and the transition after the build

Failsafes after the build

OSD and VTX after the build

QHOVER for QHOVER

QLOITER for QLOITER

The transition: FBWA for FBWA (transition)

QRTL for QRTL

AUTO: the coast survey for AUTO (coast survey)

Check yourself · Fit the tilt servos

Check yourself · Fit the airspeed sensor

Check yourself

Meet the VTOL

Practice task

VTOL tiltrotor

Design it

Calculated for this build

Checks

Cost

Build it

Try a real mistake

Selected part

Parts in the box

Wiring

Safety tests

Smoke stopper test

Motor direction check (props off)

Accelerometer calibration

Tilt servo test (props off)

Airspeed check

Pre-arm checks (props off)

MAVProxy console

Configuration snippets

QuadPlane and tilt-rotor after the build

Outputs after the build

Board, radio, GPS and airspeed after the build

Airspeeds and the transition after the build

Failsafes after the build

OSD and VTX after the build

QHOVER for QHOVER

QLOITER for QLOITER

The transition: FBWA for FBWA (transition)

QRTL for QRTL

AUTO: the coast survey for AUTO (coast survey)

Check yourself · Fit the tilt servos

Check yourself · Fit the airspeed sensor

Check yourself

Meet the VTOL

Practice task