P4 flight stability issues (v P3)

[Ken Pelletier]

I've been flying a P3P for a few months now, and just got a P4 and finding that it's not nearly as stable in flight as the P3 is in the same conditions.

For example, normal take-off / hover without touching the sticks results in very noticeable change in height and position; it doesn't hover in place as the P3 does reasonably well. It drifts higher/lower as well as laterally. This is generally true throughout flight. For example, if I lock a course and fly fwd/back the P4 drifts off course ends up in a very different location on return than on the fly out. The P3, although not 100% precise, flies the same locked course out and back gives me a fairly straight line and returns to the same point.

This is all while flying the P4 and P3 in the same location at roughly the same time; one, then the other.

Any thoughts on troubleshooting / remedying this?

All of the firmware updates have been applied, compass calibrated, strong GPS signal (18 satellites).

Thanks.

 

[msinger]

Did you try calibrating the IMU on a level surface too?

 

[Ken Pelletier]

Did you try calibrating the IMU on a level surface too?

Thanks! Yes, I had done an IMU calibration on a level surface before I began flying it, but, sure enough, doing another just now seems to have cleared things up.

 

[Kman]

I have noticed the opposite. P4 is super stable and tracks straight while my P3P wanders a bit.

 

[chris digata]

I have noticed the opposite. P4 is super stable and tracks straight while my P3P wanders a bit.

same here.. my P4 is static

 

[isopro]

A bad IMU calibration can cause instability and even a crash. Always check sensor values before take off, overtime IMU can also become uncalibrated, and might need new calibration if not in the proper range.

 

[Sim597]

A bad IMU calibration can cause instability and even a crash. Always check sensor values before take off, overtime IMU can also become uncalibrated, and might need new calibration if not in the proper range.

Is or are there some actual values or numbers you could tell me to watch for when looking at that it looks Chinese. I'm not Einstein but I'm not a complete fool, if you could tell me or us it would be much appreciated!

I can see those numbers and always wish I could make some sense outta them or tell if it looked cranky.

 

[isopro]

Is or are there some actual values or numbers you could tell me to watch for when looking at that it looks Chinese. I'm not Einstein but I'm not a complete fool, if you could tell me or us it would be much appreciated!

I can see those numbers and always wish I could make some sense outta them or tell if it looked cranky.

the Gyroscope MOD reading should be near 0, and the Acceleration MOD reading should be right around 1.0, Compass MOD 1400-1600, if they are not really close to those range, it require an IMU calibration.

 

[phantomnoobpilot]

odd. my P4 is much more stable than my P3

 

[snowghost]

Mine too.

 

[Jonah]

the Gyroscope MOD reading should be near 0, and the Acceleration MOD reading should be right around 1.0, Compass MOD 1400-1600, if they are not really close to those range, it require an IMU calibration.

Thanks for this great info. Quick question - when I look at this sensor data with the Phantom parked on a flat service with no vibrations the numbers kinda bounce around a bit. Is this normal for the data to fluctuate a bit but to be near the numbers you mention? TIA


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