Bouncing

[wwpuller]

I have a phantom 3 standard. When I fly the drone and let it hover it sits there and bounces up and down about a inch or two. I have put new blades on it but that has not help with the bouncing. Any ideas on how I can correct this problem?
Thanks

wwpuller

 

[Deleted member 62848]

I have a phantom 3 standard. When I fly the drone and let it hover it sits there and bounces up and down about a inch or two. I have put new blades on it but that has not help with the bouncing. Any ideas on how I can correct this problem?
Thanks

wwpuller

You could try imu calibration, if something not right this should sort it,got good satellites

 

[Deleted member 62848]

Oh no not again.
Let know if work or not

 

[pkozi]

I have a phantom 3 standard. When I fly the drone and let it hover it sits there and bounces up and down about a inch or two. I have put new blades on it but that has not help with the bouncing. Any ideas on how I can correct this problem?
Thanks

wwpuller

My P3 did the same with aftermarket props. I put DJI Oem props and bird flight smoothed out.

 

[wwpuller]

Is the prop part # for the p/3 9450?

 

[pkozi]

Is the prop part # for the p/3 9450?

Yes. Package says”dji 9540 self tightening rotors

 

[Deleted member 62848]

All ready says props been changed, non original props won't cause this,,,,MAN am I invisible
Last time I try help

 

[wwpuller]

ianzone thank you for your suggestions, the IMU says normal,and I show connected to eleven satellites. I did change props but they are cheap knock offs so I am waiting for DJI propellers.

 

[solentlife]

I don't think I have had a perfect hover with either my P3S or P3P ... we are talking about a heavier than air machine hanging on the thrust of four props ... varied by Flight Controller influenced by Barometer, accelerometers, gyros and GPS.
There has always been a small deviation from perfect still whenever any air movement ... ie breeze etc.

Only when absolute calm have I seen anything near still hover.

 

[pkozi]

Let us know if OEM props help

 

[Weston Ney]

That actually sounds normal to me. The Phantom 3 standard I had bounced up and down an inch or so, and side to side probably 6 inches! It will not be a problem once you are up in the air. BTW I always used oem DJI props from the DJI store.

 

[solentlife]

Agreed ... inch here and there is nothing.

 

[wwpuller]

Let us know if OEM props help

The OEM props solved the problem.

 

[solentlife]

The OEM props solved the problem.

Great ... but just trying to understand how it could be.

Flight Controller receives all the info from sensors / GPS / Barometer / Gyros etc. It then evaluates required ESC command to each motor based on this info and pilots command.

Even if a prop is slightly out from the others - the FC would detect the different results and compensate accordingly. The speed the FC does this is in decimals of a second .. faster than any pilot can do and eye can detect.

The only reason I could imagine for a non OEN prop to cause such - would be if it was flexing when FC was adjusting ESC output, causing the blade to change its pitch / thrust enough as rpm changed. That would then cause FC to adjust again and may get into oscillation as the blade flexes.

Question : Your old props - are they more flexible than the OEM ?

 

[wwpuller]

Great ... but just trying to understand how it could be.

Flight Controller receives all the info from sensors / GPS / Barometer / Gyros etc. It then evaluates required ESC command to each motor based on this info and pilots command.

Even if a prop is slightly out from the others - the FC would detect the different results and compensate accordingly. The speed the FC does this is in decimals of a second .. faster than any pilot can do and eye can detect.

The only reason I could imagine for a non OEN prop to cause such - would be if it was flexing when FC was adjusting ESC output, causing the blade to change its pitch / thrust enough as rpm changed. That would then cause FC to adjust again and may get into oscillation as the blade flexes.

Question : Your old props - are they more flexible than the OEM ?

The old props are cheap knock off brand and yes they are more flexible than the OEM

 

[solentlife]

The old props are cheap knock off brand and yes they are more flexible than the OEM

That's most likely cause then ... prop flexing as the FC is varying the motor speed to hover.

For anyone interested ... if you ever get chance to observe a fixed wing model with Slow Fly Prop vs another model with normal E prop. When the Slow Fly is rev'd up - you can see the blade disc significantly move forward as blades flex ... but the E prop barely does.

In flight - sudden throttle or manoeuvre makes the SF prop make a WOMP sound as fights the flexing. It also causes the command to lose crispness.

(I fly all sorts of models).