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0/140 of 14 done in this workshop: the build, tests, quizzes and courses
Fly itFinish the build and the safety tests first, or fly the factory-built craft.
Parts
…
Battery
unplugged
Fault
none
7-inch long-range quad on the workbench
Loading the figure…
Drag to turn it, click a part to select it. Press Escape to come back to the page.
Waiting for the figure…
The log fills as you plug in, test and fly.
Design it
Pick the battery, motors and props. Every number below is recalculated from this craft's own model.
Calculated for this build
All-up weight
925 g
Thrust : weight
5.8 : 1
Hover throttle
42%
Max current
120 A
Hover time
36.9 min
Hard-flying time
15.5 min
Checks
Parts match. Efficient and calm: a long-range cruiser.
WarningFull throttle draws 120 A, more than this pack can deliver (45 A): it will sag and heat up.
Cost
Category
Parts
Cost
Electrical
9
$394
Mechanical
4
$81
Total (approx.)
13
$475
Build it
Fit the parts in order. The figure refuses a part that cannot go on yet and tells you why.
Parts 0/13
1.Start with the framenot fitted
2.Screw on the four motorsnot fitted
3.Mount the 4-in-1 ESCnot fitted
4.Solder the motor wiresnot fitted
5.Solder the XT60 and the capacitornot fitted
6.Stack the flight controller, arrow forwardnot fitted
7.Fit the VTX and its antennanot fitted
8.Fit the cameranot fitted
9.Fit the 900 MHz receivernot fitted
10.Fit the top plate and the GPS mastnot fitted
11.Mount the GPS on the mastnot fitted
12.Strap on the Li-ion packnot fitted
13.Fit the props, lastnot fitted
Try a real mistake
Fit a part the wrong way on purpose and see which test or flight catches it.
Selected part
Nothing selected. Click any part on the figure, a wiring block, or a name in the list.
Parts in the box
Wiring
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:→6S · 22.2 V nominal, 25.2 V full
The pack plugs into the XT60. 6S is 25.2 V full and 22.2 V nominal (21.6 V for Li-ion's 3.6 V cells). A punch-out pulls up to 120 A, far above what a 45 A Li-ion pack likes.
power:→VBAT pads · 12 AWG
12 AWG leads to the ESC's battery pads, with the 1000 µF 35 V low-ESR capacitor across them.
motor phases:→3-phase ×4 · M1-M4 pads
Three phase wires per motor. Any order spins it; swapping two, or reversing it in the ESC firmware, turns it the other way.
data / signal:→DShot600 ×4 · 8-pin harness
The 8-pin harness: four DShot600 motor signals (bidirectional, so each ESC reports rpm), battery voltage, ground and the current sensor.
data / signal:→UART2 · CRSF · 5 V
ELRS on UART2 with CRSF: receiver TX to RX2 and RX to TX2, plus 5 V and ground. Both wires matter: telemetry (LQ, RSSI, battery) goes back to the radio.
data / signal:→UART3 · UBX 57600 + I2C · 5 V
One 6-pin lead: GPS TX to RX3 and RX to TX3 (u-blox UBX at 57600 baud once Betaflight has configured it), the compass's SDA and SCL to the I2C pads, 5 V and ground.
video:→CAM pad · CVBS · 5 V
Camera video into the CAM pad, with 5 V and ground. The flight controller's analog OSD writes the GPS, link and battery data over it.
video:→VTX pad + UART1 TX SmartAudio · 9 V
Video with the OSD out of the VTX pad, 9 V from the flight controller's BEC, and SmartAudio from TX1 so Betaflight sets the band, channel and power.
Safety tests
Real builds get these checks before the first flight. Run them in order: the figure enforces what each one needs.
Tests 0/6
1.
Smoke stopper test
Not run yet
How it is done
A smoke stopper (a fuse or current-limiting lamp in the battery lead) goes between the pack and the craft for the very first power-up. If something is shorted, the lamp lights instead of the ESC burning.
2.
Motor direction check (props off)
Not run yet
How it is done
Props off, battery in: spin each motor alone from the Motors tab and compare its direction with the frame diagram. A wrong one is reversed in the ESC configurator, never by guessing.
3.
Accelerometer calibration
Not run yet
How it is done
With the craft on a level surface, calibrate the accelerometer so the self-levelling modes know which way is down.
4.
Compass calibration and heading check
Not run yet
How it is done
Rotate the craft through every axis until the compass calibration completes, far from steel and power cables.
5.
GPS lock (outdoors)
Not run yet
How it is done
Wait for enough satellites and a good position fix before arming in a GPS mode.
6.
Failsafe and rescue test (props off)
Not run yet
How it is done
Props off and armed, switch the radio off: the craft must carry out its failsafe action, not hold the last stick positions.
Betaflight CLI console
A working emulation of the Betaflight command line for this craft: real setting names, real limits and real error messages.
Entering CLI Mode, type 'exit' to return, or 'help'
Up and down recall earlier commands.
Configuration snippets
First setup after flashing after the build
Sets the mixer, the board alignment and DShot600 with bidirectional telemetry for the RPM filter; motor_poles is 14 for these 12N14P motors. Each serial line gives a port its job: 64 is the ELRS receiver on UART2, 2 is the GPS on UART3 at 57600 baud, and 2048 is SmartAudio on UART1, which only needs the TX wire. resource prints the pin map so you can check the motor, UART and I2C pins against the board.
# Betaflight 2026.6.2 on an F7 stack: ELRS on UART2, GPS on UART3, compass on I2C, SmartAudio on UART1mixerQUADXset align_board_yaw = 0# FC arrow to the nose; 180 if it points backset motor_pwm_protocol = DSHOT600set dshot_bidir = ON# RPM telemetry for the RPM filter (AM32 or Bluejay)set motor_poles = 14# 2806.5 / 2807 motors are 12N14Pset yaw_motors_reversed = OFF# props inserialUART264115200576000115200# 64 = serial RX (ELRS, CRSF)set serialrx_provider = CRSFserialUART32115200576000115200# 2 = GPS, 57600 baudserialUART12048115200576000115200# 2048 = SmartAudio (VTX)resource# check the motor, UART and I2C pinssave
GPS and compass after the build
feature GPS turns the GPS on and gps_auto_config lets Betaflight set up the u-blox module itself (rate, constellations, Galileo). The compass is found on I2C; align_mag tells Betaflight how it sits: CW270FLIP is right for a Matek M10Q-5883 with its arrow to the nose, other modules differ, so check the heading. Since 2026.6 the compass is ignored for heading unless trust_mag is ON: switch it on only after calibrating and checking it.
# GPS + compass: u-blox M10 on UART3, QMC5883L on I2CfeatureGPSset gps_provider = UBLOXset gps_auto_config = ON# the FC configures the u-blox module itselfset gps_ublox_use_galileo = ONset mag_hardware = AUTOset align_mag = CW270FLIP# Matek M10Q-5883 with its arrow to the nose; check yoursset trust_mag = ON# only after the compass is calibrated and the heading checkedsave
GPS Rescue as the failsafe for GPS Rescue
When the link is gone for failsafe_delay (1.5 s), GPS Rescue climbs, turns for home, flies back at 7.5 m/s and starts down 20 m out. return_alt only counts with FIXED_ALT; the default MAX_ALT returns at the highest height since arming plus 10 m, which can be below a ridge if you flew low along a valley. With fewer than 8 satellites Betaflight will not arm (flag GPS). FS_ONLY means a failed check in a real failsafe (no home, GPS lost, not closing on home for 20 s) ends in a descent where it is. ap_hover_throttle tells the autopilot this quad's real hover, 1420 µs. The aux line puts GPS RESCUE (mode 46) on a switch for testing.
# GPS Rescue: on failsafe it climbs, turns for home, flies back and lands.# Test it close in before you trust it far out.set failsafe_procedure = GPS-RESCUE
set failsafe_delay = 15# 1.5 s of stage 1 before the rescue startsset gps_rescue_min_sats = 8# fewer satellites: arming is blocked (flag GPS)set gps_rescue_alt_mode = FIXED_ALT# without it, return_alt is ignoredset gps_rescue_return_alt = 45# metres: clear the highest ridgeset gps_rescue_ground_speed = 750# cm/s on the way home (7.5 m/s)set gps_rescue_descent_dist = 20# metres from home where it starts downset gps_rescue_sanity_checks = RESCUE_SANITY_FS_ONLYset ap_hover_throttle = 1420# this build hovers at about 42 % throttleaux34631700210000# GPS RESCUE (mode 46) on AUX4 high, to test itsave
Stage 1: hold the throttle after the build
For 0.3 s after the link drops every channel holds its last value; then each takes its rxfail value until failsafe_delay ends. By default the throttle goes low, so a cruising 7-inch drops for over a second before the rescue starts. rxfail 3 h makes the throttle (channel 3: roll, pitch, yaw, throttle count from 0) hold its last value instead. The four flight channels only take a (auto) or h (hold).
# Stage 1 of a failsafe: 0.3 s of held sticks, then every channel takes its rxfail valuerxfail # list them: throttle is "a" (auto = low) by defaultrxfail 3 h # throttle (channel 3) holds its last value until the rescuesave
Li-ion voltage alarms after the build
Betaflight's defaults are LiPo numbers: a warning at 3.5 V a cell and the minimum at 3.3 V. A Li-ion cell still has about half its energy at 3.5 V and is used down to about 3.0 V under load (the cells are rated to 2.5 V), so the warning goes to 3.1 V and the minimum to 2.9 V. bat_capacity lets the OSD warn on mAh used too; set it to your pack.
# 6S1P 21700 Li-ion: the LiPo alarms would sound with half the energy leftset vbat_warning_cell_voltage = 310# 3.10 V per cell: turn for homeset vbat_min_cell_voltage = 290# 2.90 V per cell: land nowset vbat_full_cell_voltage = 410set bat_capacity = 4000# mAh, for the capacity warningsave
The long-range OSD after the build
Each _pos value is 2048 (OSD profile 1) plus the column plus 32 per row. Top left are the link quality and the RSSI in dBm, the two numbers that warn you the link is getting thin; along the top, the home arrow, the distance home and the satellite count; speed and altitude at mid height; the warnings in the middle, where RESCUE N/A, RESCUE FAIL and HEADING N/A show; the flight mode, volts per cell, amps and mAh along the bottom.
A SmartAudio 2.1 VTX takes its power in dBm: 14, 20, 26 and 30 dBm are 25, 100, 400 and 1000 mW. vtx_power picks a level from this table, 1 being the lowest. Keep 25 mW on the bench and low power until armed (vtx_low_power_disarm), and raise it only when you fly far: 1 W runs hot.
# 1 W SmartAudio VTX: power levels in dBm (bands and channels as for the 5-inch)vtxtable powerlevels 4vtxtable powervalues 14202630vtxtable powerlabels 251004001W
set vtx_power = 1# 25 mW on the benchset vtx_low_power_disarm = ON# lowest power until armedsave
Switches: arm, angle, altitude hold, rescue, beeper after the build
aux takes the mode's number: 0 ARM, 1 ANGLE, 3 ALTHOLD, 46 GPS RESCUE, 13 BEEPER. The channel counts from 0 = AUX1, and the range is in microseconds. The GPS RESCUE switch lets you test the rescue close in, and take it on purpose when the video breaks up; the beeper helps you find the quad in long grass.
# aux <slot> <mode id> <AUX n - 1> <from us> <to us> <logic> <linked>aux0001700210000# ARM on AUX1 highaux1111300210000# ANGLE on AUX2 mid + high (low = acro)aux2321700210000# ALTHOLD on AUX3 high (barometer + GPS)aux34631700210000# GPS RESCUE on AUX4 highaux41341700210000# BEEPER on AUX5 high: find it in long grasssave
Altitude hold for Altitude hold (easy)
ALTHOLD holds the height with the barometer and the GPS. Centred throttle holds; the deadband is the 20 % of stick round the centre that counts as centred, and full stick climbs or sinks at 3 m/s (30 tenths).
# Altitude hold (barometer + GPS): W/S climb and sink, centre the stick to holdaux2321700210000# ALTHOLD on AUX3 highset alt_hold_climb_rate = 30# full stick climbs 3 m/s (units 0.1 m/s)set alt_hold_deadband = 20# % of stick around the middle that holds heightsave
Angle mode for Angle mode
The flight controller levels the quad when you let go and never tilts it past angle_limit: 45 degrees here, plenty to cruise and gentler than the default 60.
# Angle mode: self-levelling cruise, tilt cappedaux1111300210000# ANGLE on AUX2 mid + highset angle_limit = 45# max tilt in degrees (10-80, default 60)save
Soft acro rates for Acro (rate) mode
Acro is what flies with angle and altitude hold off: the sticks set the rotation rate and nothing levels it. Under ACTUAL rates 7 and 50 give 70 degrees a second round the centre and 500 at full stick, soft for a heavy 7-inch. Yaw stops at 200.
# Acro: the sticks set rotation rates, nothing levels it. Soft rates for a heavy 7-inch.set rates_type = ACTUALset roll_rc_rate = 7# 70 deg/s around centre stickset pitch_rc_rate = 7set yaw_rc_rate = 7set roll_srate = 50# 500 deg/s at full stickset pitch_srate = 50set yaw_srate = 20# 200 deg/s yawsave
Gate timer for Farmhouse gates (angle)
osd_tim1 packs the timer source and precision into one number: 2 (since the last arm) plus 1 x 16 (hundredths) is 18. Its position, 2135, is 2048 plus column 23 plus row 2 x 32.
# Five gates by the farmhouse, in angle mode, against the clockaux1111300210000# ANGLE on AUX2 mid + highset osd_tim1 = 18# timer 1: time since the last arm, hundredthsset osd_tim_1_pos = 2135# column 23, row 2save
The valley run for Range: Mountain valley
Fly it in altitude hold, so the height looks after itself while you follow the river. The home arrow and the distance stay on the OSD: when the battery says turn for home, they show the way back.
# Valley run in altitude hold: river, lake, saddle, tower top, homeaux2321700210000# ALTHOLD on AUX3 highset osd_home_dir_pos = 2094# the home arrow shows the way backset osd_home_dist_pos = 2125save
Check yourself · Solder the XT60 and the capacitor
Check yourself · Mount the GPS on the mast
Check yourself · Strap on the Li-ion pack
Check yourself
Meet the long-range quad
A 7-inch long-range quad trades a 5-inch's punch for efficiency: big, low-pitch props turned slowly by 1300 KV motors, and a 6S1P pack of 21700 Li-ion cells that holds about twice the energy per gram of a LiPo. A GPS and compass on a mast tell Betaflight where home is, and an ExpressLRS 900 MHz link reaches several kilometres. If the link is lost, GPS Rescue climbs, turns for home, flies back and lands. This one has a 315 mm True-X carbon frame, a 30.5 mm F7 stack and a 1 W analog video transmitter. Pick the pack, motors and props and watch the flight time change, build it part by part, run the compass, GPS and failsafe checks with the props off, then fly the valley.
Practice task
Fly the farmhouse gates to get the feel of a heavy 7-inch, then the valley run with an eye on the home arrow, then watch GPS Rescue bring it home. On a real long-range quad: calibrate the compass and check its heading against a phone, wait for 8 or more satellites before you arm, and test the rescue close in (50 to 100 m out, switch GPS RESCUE on and watch it come back) before you trust it far out. Turn for home at 3.1 V a cell, and know the rules where you fly: most countries want the quad within sight, or a spotter next to you.
Build it, lock the GPS and test the rescue with the props off, then fly the valley