Holy Stone Quadropter Back Left Motor Wont Star

It's frustrating, but not uncommon that FPV drone flips over when trying to take off. Usually, the issue is due to wrong configuration or faulty parts. In this guide I will help you troubleshoot the problem.

If you followed my mini quad building and setup guide, you should have eliminated many potential causes that can ruin your first take off. It's not too late to check it out :) You might still learn something.

Now, let's get back to work!

Prop Nuts Fastened?

A motor with loose propeller generates little to no lift. Make sure all the prop nuts are fastened tightly, and that the props are unable to move when holding down the motor.

Pro tip: Looking for a good prop nut wrench? This is what I personally use: http://bit.ly/2USCEgM;

Good thing is you can just keep fastening until it's done without lifting the wrench once.

Mechanical Installation

Make sure all all the hardware are installed snugly: no loose screws, frame parts, flight controller, motors etc…

Did You Put the Props On Correctly?

The propellers should be installed as shown in the above image. Pay attention to the prop leading edge.

Also, make sure they are not installed upside down. The up side usually has a glossy finish with extruding model numbers, while the bottom side has a matte finish without numbers.

Further Reading: Learn about the basics of quadcopter propellers

Incorrect Motor Order

You should now remove all the propellers for the rest of this troubleshooting guide.

Go to the motor tab in Betaflight Configurator, on the top of the page, you should see a quadcopter diagram, with the four motors labelled 1, 2, 3 and 4.

This is how the motors are numbered in Betaflight: rear right motor is #1, front left motor is #4 and so on… It's not the most intuitive, I know… anyway…

Spin the motor up one by one in the Motor tab, and see if the motor that spins matches the motor number.

What to do if the motors are in the wrong order?

You can swap the ESC signal wires around on the flight controller. Alternatively, if you don't like soldering, you can also remap motor output in Betaflight CLI.

Motors Spinning the Wrong Direction

Check spin direction of the motors, and make sure they match the arrows in the this diagram on the motor tab.

Pro tip: What's the easiest way to physically figure out which way the motors are turning without props on?

Simply touch the motor bell lightly when it's spinning, and letting your finger drag across the bell. You can tell which way the motor is turning as you should feel more resistance if the bell is spinning the opposite direction.

If the motors are all spinning the opposite direction, you can simply toggle the option "Reverse Motor" in the Configuration tab in Betaflight Configurator.

Otherwise you would have to manually reverse the motor direction – either by swapping the motor wires, or reversing motor direction in ESC setting (BLHeli_Suite).

Motor Screw Touching Winding?

If a motor screw is too long and touching the motor windings, it basically creates an electrical short in the motor. It might appear to spin up just fine when you arm it, but the quad could just flip over immediately when trying to get it off the ground.

If you leave it running like this long enough, the motor might overheat, and eventually fry the motor and ESC.

Here is how to check if your motor screws are touching the windings.

Flight Controller Orientation

You will need Accelerometer to check your flight controller orientation, so please enable Accelerometer in the Configuration Tab first.

Then go to the Setup Tab, where you should see a 3D model of a quadcopter, representing your quad.

As you move your quad around, the 3D model should follow the movement. Make sure it rotates in the exact same direction. If not, it's probably the wrong flight controller orientation.

You can either rotate your flight controller manually in the quadcopter, or you can change the "board alignment" setting in Betaflight.

Go to the Configuration tab, under "Board and Sensor Alignment", and change Yaw degrees. If you don't know what to change it to, just try 0, 90, 180 and 270, one of these values should normally work.

Turtle Mode Enabled By Accident?

Turtle mode (aka "Flip over after crash") is a very useful feature. It flips over your quad when you are downed and overturned. But when you have Turtle mode enabled by accident, you might have trouble taking off.

Further Reading: How to Setup Turtle Mode

If your quad does not respond to throttle changes, but simply flips out when you touch pitch or roll, this is probably it. If you have Betaflight OSD enabled and showing "warning", you should see "CRASH FLIP" in your OSD to confirm this.

Further Reading: How to Setup Betaflight OSD

If this is indeed the case, check if you are activating the feature by mistake. Or you can simply try disabling "Flip Over After Crash" in the modes tab.

ESC Protocol

If you use ESC protocol that your ESC doesn't support, then your quad might behave unexpectedly. You should confirm this in the ESC specs.

Further Reading: ESC Protocols and Firmware Explained

If you are not sure, try Standard PWM which is supported in all ESC's. This will allow you to rule out whether it's a protocol related issue.

You can change ESC protocol in the Configuration tab.

ESC Calibration

You don't need to calibrate ESC if you are running DShot. But if you are not (like PWM, Oneshot or Multishot), then you should calibrate your ESC's.

If one or multiple ESC's in your quadcopter are not calibrated properly, they could have an later starting point than others. Usually it can cause some performance issues, not as bad as making the quad to flip out at takeoff, but it's worth checking.

Here is how to calibrate ESC.

Check Motor Mixer

In the Configuration tab, you should see an option called "Mixer". It basically chooses which motors to run, and changes the percentage of throttle applied to each motor. You only want to play with this when you run an unusual frame or motor configuration.

For a normal quadcopter, you should just leave it at default – "Quad X".

Is Receiver Working Correctly?

Go to the Receiver tab, and make sure the bars are moving in the correct order to your stick inputs. Note that some flight controllers might require LiPo battery plugged in, in order to power up the receiver.

If the channel order is wrong, simply try a different "channel map" – it's usually either TEAR (Default) or AETR for most people.

And also make sure the bars are moving in the correct direction:

Throttle value increases as you move throttle stick up
Yaw value increases as you move yaw stick right
Pitch value increases as you move pitch stick up
Roll value increases as you move roll stick right

If they move in the opposite direction, you can revert that channel in your radio setting. The steps depend on what radio you use, so better to just google how to do it :)

Try Acro Mode

Acro mode only uses the Gyro and doesn't use Accelerometer, while Angle and Horizon modes use both sensors.

An un-calibrated or broken Accelerometer can cause the flight controller to "freak out" when you are trying to take off in Angle mode or Horizon mode. So please try to take off in Acro mode and see what happens.

Reset Settings and Update Firmware

Maybe there are wrong settings in Betaflight causing your problem, and it's not a bad idea to start fresh by wiping the entire configuration. There is a "Reset Settings" button in the Setup tab in Betaflight Configurator. You might want to backup your settings first just in case.

Also I would recommend updating your firmware to the latest stable version to take advantage of the most recent bug fixes.

Here is how to update Betaflight firmware.

Bad Motor or ESC?

If nothing helps so far, then we are going to check the motor and ESC.

A faulty motor or ESC can cause the quad to flip out. If it always flips toward the same direction then that's probably it.

If you are not sure if it's the motor or ESC, try swapping around just the motor with another one on the same quad, and see if the problem follows that component.

If yes, then you find the cause. If not, repeat with the ESC.

4S is Fine, But Flips Over on 6S

Very likely to be a gyro calibration issue.

What is probably happening here is that at 6S voltage, there is more regulator noise or something else is increasing the electrical noise floor, so the gyro cannot calibrate.

One thing you can try is to Increase gyro_calib_noise_limit.

These settings control how long Betaflight waits to calibrate the gyro zero, as well as limiting how much is acceptable noise to complete the calibration.

Still having problems?

If none of these suggestions helped, then it's possible that you might have a dead flight controller, or maybe a bad gyro that needs replacing.

You might or might not see symptoms like constantly spinning 3D model in the Setup page, or disarm flag saying "NO GYRO".

Anyway, for more advice, please join our forum IntoFPV, we are happy to help!

Holy Stone Quadropter Back Left Motor Wont Star

Source: https://oscarliang.com/quad-flip-over-issue-fix/