Multirotor (4) crashing after takeoff

ArduCopter
1

Hello there!
As a group of 5, we have been building a quadcopter for our school project. Even though our quadcopter stays fairly stable for around 5-6 seconds flying, it rolls and crashes right after that.

We are using a SpeedyBee F405 Wing APP and a JawsPawer 5000mah 3S LiPo battery. The logs show that voltage is sagging too much. Our battery claims that it is 100C but we don’t trust it as we got it from a really cheap store. We’ll try again with a Turnigy 2200mah 35-45C LiPo battery after I write this and I’ll add more to this post with those results after that flight.

If anyone could give a second look at the logs that would be greatly appreciated.
FYI: Motors: RS2205 RaceStar *4, esc: skywalker 30A *4. 7 inch props.

Thank you!

Logs: Unique Download Link | WeTransfer

2

Configure the vehicle correctly to avoid all these issues. And ask questions if you need help.

Most time it is caused by incorrect motor order and/or propeller mount.

3

If the copter tries to flip over immediately when throttling up, then it’s motor order.
Use the MissionPlanner motor test extensively.
Use the RC Calibration screen check your RC pitch channel is working the correct way around, it’s opposite to what is usually expected.

1 Like
4

No it’s not immediately trying to flip over, it stays stable for around 2-3 seconds then tries to flip.

The motors are in this order (found here):

m_01_01_quad_x
m_01_01_quad_x743×743 53.3 KB

And yes I assured the FC faces the way shown in the image

It should be correct, we even reversed the pitch channel to accommodate for ardupilot’s default configuration.

Also some new logs from theTurnigy battery, we are experiencing the same issue.

5

I don’t think anyone here is going to look at 7 logs. Just send the most recent or the best example of the issue. I picked one file to look at.

image
image1501×837 76.5 KB

The quad is under powered or over weight. With motor outputs that high it should be climbing.

You should also be doing your tests in stabilized mode.

Use the configurator tool that was linked above to get things set up right so you can set up your filters before you start to tune.

1 Like
6

In our recent tests drone is lifting up to 2 meters but any higher the drone becomes unstable and either falls or does a battery failsafe and lands. I believe as you said our drone is probably overweight for these small motors. We will consider redesigning the frame.

7

Use this:
eCalc

8

If you are redesigning the frame, read the hardware best practices that i posted in the first link avove