P4 wiggle

[reds2tall55]

Hello everyone! Hope everyone has a awesome day, question....I have a now 7flight old P4 and only really 46 mins with all 7 flights anyway yesterday I took off to a hover over the White House lawn... just kidding.. anyway my bird started this wiggling thing... any ideas?

 

[Fly Dawg]

anyway my bird started this wiggling thing... any ideas?

Maybe, if you could describe this "wiggle" a bit more clearly. Or better yet a short video. Could be any number of issues. Off the top of my head I would guess the VPS. You could turn that off and give it a shot. Other than that, a much better description is in order.

 

[WV. Rootman]

My P4 was doing it last night also. If you turn off the sensors it should stop. I wouldn’t turn them off while you are learning. I have been flying awhile and I still leave them on till I get well above tree top. I go out of P mode to get more speed. My perception is off a little, so I leave them on closer to the ground. Seems like mine do the wiggle more coming down and in a little fast.

 

[Fester]

My P4 was doing it last night also. If you turn off the sensors it should stop. I wouldn’t turn them off while you are learning. I have been flying awhile and I still leave them on till I get well above tree top. I go out of P mode to get more speed. My perception is off a little, so I leave them on closer to the ground. Seems like mine do the wiggle more coming down and in a little fast.

If the "wiggle" is noted during descent, say during a RTH initial descent at around 6.5 MPH, the bird is encountering its own propwash as it descends. As the vertical speed reduces nearing the ground/launch point, the "wiggle" will disappear.

 

[Fly Dawg]

As the vertical speed reduces nearing the ground/launch point, the "wiggle" will disappear.

True, unless the VPS information is conflicting during landing, then the AC may exhibit a "bounce" and/or "wiggle" effect as noted above.

 

[Mimoid]

If the "wiggle" is noted during descent, say during a RTH initial descent at around 6.5 MPH, the bird is encountering its own propwash as it descends. As the vertical speed reduces nearing the ground/launch point, the "wiggle" will disappear.

No, the thing you are referring to (vortex ring state) is not an issue with the P4 because of the prop shaft alignment design. Older Phantoms (particularly the first version) could sometimes encounter this state and the whole bird could then wobble around quote a bit during descent, but it was changed in later designs.

In fact, with my P4 I often drop with max vertical speed with the stick straght down (for instance when I am between trees) and my footage is rock steady.

 

[Fester]

No, the thing you are referring to (vortex ring state) is not an issue with the P4 because of the prop shaft alignment design. Older Phantoms (particularly the first version) could sometimes encounter this state and the whole bird could then wobble around quote a bit during descent, but it was changed in later designs.

In fact, with my P4 I often drop with max vertical speed with the stick straght down (for instance when I am between trees) and my footage is rock steady.

My P4 std. has always exhibited this behavior when descent speed is around 6.5 mph such as during the initial phase of descent on RTH, but goes away when the bird slows its descent same behavior with either the std. props or the new "low noise" props. I have no known problems with the downward sonar or the VPS, as usually the landing is spot on. Next flight just out of curiosity I'll do an atti mode landing just to see if the "wiggle" remains at the higher vertical speed. The "wiggle" no matter the cause, is cancelled out by the gimbal and the footage is quite stable.

 

[happydays]

Was it overly windy? Was the wiggle reflected in the video (were you taking video?) or in the FPV?

 

[Erised]

If you are within VPS range and the craft maintains position and wiggles it is compensating for wind in order to maintain your position, if it drifts off the VPS doesn't have a lock on the ground and the craft should use GPS to return close to hold position, depending on the surface you are landing on this at time gets squirlly. Sometimes the wind has small gust that change slightly in direction and your craft will compensate (wiggle), that's normal. When you are up and out of VPS range the craft will wiggle to compensate for wind and may slightly drift and come back to the holding position (within GPS capabilities)

 

[offroadpyro]

Sou like propellers not the a.c..Check to see if they are balanced.Also let motors idle, do you see one propeller wobble.I'm betting that you do.Another way to test propellers measure the distance the propeller is from body.Make sure both sides of propellers have same distance height from body on top of a.c..

 

[Mimoid]

My P4 std. has always exhibited this behavior when descent speed is around 6.5 mph such as during the initial phase of descent on RTH, but goes away when the bird slows its descent same behavior with either the std. props or the new "low noise" props. I have no known problems with the downward sonar or the VPS, as usually the landing is spot on. Next flight just out of curiosity I'll do an atti mode landing just to see if the "wiggle" remains at the higher vertical speed. The "wiggle" no matter the cause, is cancelled out by the gimbal and the footage is quite stable.

Vortex rings during vertical descent is a rather violent phenomen that would result in the Phantom pretty much drop like a stone to the ground, not just "wiggle" a bit. In some rare cases the P2 could enter vortex ring state and crash, but DJI claims that it cannot occur with the P3 or P4 as the descent speed is limited, and also because of the slightly slanted prop shafts.