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Quadcopter flips on takeoff

kopolo

New member
#1
Hi all
I have built a drone with 420 Lite ESCs and dji E series motor. My FC is F4SD.
After following tutorials on betaflight, my drone seems to flip upon takeoff.
Upon inspection, it seems that the motors are not in sync.
At 25% throttle, some motors would be at 60% speed, whilst at 50% throttle, some motors would be at a 100% speed while others would just barely turn on.
What seems to be the issue here? I have replaced all components.
For inspection, a 12Vdc power generator is used, so there should be no power issues.
 

kopolo

New member
#2
i should also mention that my receiver is flysky fs ia6b. My transmitter is is flysky fs i6x.
beta flight config:
Min throttle : 1050
Max throttle : 2000
UART port used : 1 ( due to burning out 6)
 

JasonK

Master member
#3
go into betaflight and with your props removed, test each motor individually, making sure the expected motor spins up and in the expected direction.

You most likely have the motors miss-aligned on the frame vs the configuration in betaflight, causing it to 'correct' itself incorrectly.
 

kopolo

New member
#4
go into betaflight and with your props removed, test each motor individually, making sure the expected motor spins up and in the expected direction.

You most likely have the motors miss-aligned on the frame vs the configuration in betaflight, causing it to 'correct' itself incorrectly.
will try that tomorrow, i will check the orientation of each motors ! update again
thanks!
 

PsyBorg

Wake up! Time to fly!
#6
With your props removed go to the motors tab and enable motors. Spin each one up one at a time. Check to be sure they turn the proper direction as well as are in the correct position on the quad.

Since these are DJI esc's I'm gonna take a guess they are not Dshot digital enabled and probably need to be calibrated which is what sounds like the reason for the motor response you are having.

Reconnect to betaflight with props still off. Go back to motors tab and raise the main slider to full. Plug in a flight battery and when you hear the esc's start to make boot up tones slide the main motor slider back to 0. The esc's should reboot. then use the main slider just a touch to see if all the motors start up at the same time as well as read roughly the same number in betaflight.

At that point you can unplug and disconnect from betaflight. STILL with props off boot your radio. Then your quad. Arm the quad and let it idle. Lift it up and the motors should even out with only slight changes as your hand is not stable enough to hold it perfectly still. Tilt each corner down one at a time. As that corner goes lower then the rest of the quad that motor should speed up. If all 4 act correctly then you will be safe to put props on and try to hover again.
 

kopolo

New member
#7
With your props removed go to the motors tab and enable motors. Spin each one up one at a time. Check to be sure they turn the proper direction as well as are in the correct position on the quad.

Since these are DJI esc's I'm gonna take a guess they are not Dshot digital enabled and probably need to be calibrated which is what sounds like the reason for the motor response you are having.

Reconnect to betaflight with props still off. Go back to motors tab and raise the main slider to full. Plug in a flight battery and when you hear the esc's start to make boot up tones slide the main motor slider back to 0. The esc's should reboot. then use the main slider just a touch to see if all the motors start up at the same time as well as read roughly the same number in betaflight.

At that point you can unplug and disconnect from betaflight. STILL with props off boot your radio. Then your quad. Arm the quad and let it idle. Lift it up and the motors should even out with only slight changes as your hand is not stable enough to hold it perfectly still. Tilt each corner down one at a time. As that corner goes lower then the rest of the quad that motor should speed up. If all 4 act correctly then you will be safe to put props on and try to hover again.
Thanks for your help.I have already tried calibrating countless times , the motors still do not read roughly the same values, the disagreement is very large. At max throttle, motor 2 could be showing 2000 whilst motor 4 could be at 1300.
Could there be any other issues?
 

JasonK

Master member
#8
In the BetaFlight OSD tab, make sure you turn Warnings on, then you can see in the goggles what the warning is when you arm.
if they managed to have the quad flip, it managed to arm. adding the warnings to the screen would only help (from what I can see) if it wasn't arming.
 

CappyAmeric

Well-known member
#9
You can't judge motor proportional values on the bench with props off. BetaFlight doesn't work that way. All you can test in that regard is whether the motors are turning the correct direction (and of course whether the correct props are physically mounted).

Connect the quad to BetaFlight. Go to the Setup tab. Does the BetaFlight quad display show your quad level on the table? If not, calibrate the accelerometer.

If it matches, then pick up the quad - does the BetaFlight quad display move consistently with movement in all axis when you move the quad? Tilt forward, tilt back, roll left, roll right, yaw left, yaw right. If not, then you may have a mis-mounted flight controller (sideways, or upside down), or the gyro orientation in the Configuration tab is incorrect.

If all that is working as expected, go to the BetaFlight Receiver tab. Power your transmitter, and plug a battery into the quad. As you move the sticks watch the preview window in BetaFlight - does the quad pitch, roll, and yaw in the correct direction? If not, you may need to change the channel mapping.
 

kopolo

New member
#10
You can't judge motor proportional values on the bench with props off. BetaFlight doesn't work that way. All you can test in that regard is whether the motors are turning the correct direction (and of course whether the correct props are physically mounted).

Connect the quad to BetaFlight. Go to the Setup tab. Does the BetaFlight quad display show your quad level on the table? If not, calibrate the accelerometer.

If it matches, then pick up the quad - does the BetaFlight quad display move consistently with movement in all axis when you move the quad? Tilt forward, tilt back, roll left, roll right, yaw left, yaw right. If not, then you may have a mis-mounted flight controller (sideways, or upside down), or the gyro orientation in the Configuration tab is incorrect.

If all that is working as expected, go to the BetaFlight Receiver tab. Power your transmitter, and plug a battery into the quad. As you move the sticks watch the preview window in BetaFlight - does the quad pitch, roll, and yaw in the correct direction? If not, you may need to change the channel mapping.
Hello, thanks for the reply.
I have checked everything and test flight today. The drone takes off , slants and starts to freak out , as a cockroach would when you turn on the lights.
I have no idea what went wrong . The drone just would not take off. Turtle is off, Min throttle value 1140 , max 2000.
Rx is ok, working fine on UART 3.
Any suggestions? Thank you!
 

CappyAmeric

Well-known member
#11
Hello, thanks for the reply.
I have checked everything and test flight today. The drone takes off , slants and starts to freak out , as a cockroach would when you turn on the lights.
I have no idea what went wrong . The drone just would not take off. Turtle is off, Min throttle value 1140 , max 2000.
Rx is ok, working fine on UART 3.
Any suggestions? Thank you!
Great. It sounds like what I suspect is an orientation problem or channel mapping. In BetaFlight's Receiver tab, what is your channel mapping AETR1234? Also, in BetaFlight, go to the CLI tab and type VERSION and press <ENTER> and tell me flight controller target and version.
 

PsyBorg

Wake up! Time to fly!
#14
Go to the CLI tab and type Diff then hit enter. Copy that whole thing in a text file and paste it in this thread please. that will show us ALL the settings

Also be sure that the betaflight configurator and the . hex file for that specific flight controller are the same revision. With an F4 flight controller you should not be on anything higher then 4.2
 

CappyAmeric

Well-known member
#15
Also, upon backup, the terminal shows this:
This video link is to Joshua Bardwell's build instructions for BetaFlight. Since you have already done a lot of this, perhaps just skip to about 11:00 and make sure your receiver and channel mapping is correct. Follow the steps he does in the Receiver tab, including setting your channel mapping, and channel end points.