Do all p4 owners experience yoyo when stopping?

[John Locke]

How do you mean that the altitude is flawed?
I noted that the my P4 dropped maybe 7-8 meters when it stopped after it had been flying quite fast for a while but the altitude report was constant during the drop so the P4 just tried to maintain its height!
Is this sensor error due to heat or something else?

I wonder what the DJI fix actually is doing?

/hakan

The original yoyo for me was dropping about 8' then rising back up. This occurred when stopping from forward motion. For the most part this has been resolved with the new firmware. However, I do notice that sometimes it will rise up 3-4' occasionally, but I can deal with that most the time. It's still not as stable as my P3P when comparing vertical stability, but it got closer with the latest firmware.

What I'm seeing for altimeter is about a 50' deviation from reality, which I've never seen before. This doesn't happen 100% of the time, but most of the time. After a flight when I return to my launch site the altitude will say something like 60' high, when it's really only 10' high. I noticed this when I was flying a Litchi mission from a cliff, but when it returned back to home, which was my last waypoint, set at 10' high. The craft would have crashed into the cliff had I not stopped the mission. When I brought the craft in manually the altimeter stated 63' high, and in reality it was only 8' above launch point. The strange thing about this is the VPS vertical sensors should work below 30', and it should be accurate, but it's not. I need it to be accurate for Litchi missions at all levels, but it's off about 50 to 60' off from time to time. Very strange. I see others reporting similiar experiences, so I assume this flaw was introduced into the last firmware that fixed the yoyo. I think DJI has a bigger problem with the P4 barometer and they are struggling to fix it with a firmware patch. This is should be easy to fix in firmware if the barometer is working right, but I have a hunch something else is going on in the hardware. I don't like being so cynical, but this yoyo issue, and now this altimeter issue has me wondering. I don't think DJI tests new firmware very much, these new flaws aren't that hard to spot.

 

[Alien Warrior]

I sent my P4 for repair. Body was replaced but gimbal is original.
Have only tested on one battery so far but appears to fly without any further yoyo issues.

 

[KevMo Photog]

My P4 yoyo'ed so badly it made getting usable footage nearly impossible.
Several hours of flight and all i managed was 10 minutes of usable non-yoyo'ing footage.
DJI Ken refused to acknowledge there was a problem with yoyo'ing and insisted I return the P4 for repair. 2 days later after sending the P4 back to China a FW update was released that supposedly addressed the issue!

Currently very grumpy as I have not had the P4 for longer than I had the P4 for.
Flew it for three weeks and gone now for 4 weeks!

BTW.... out of desperation to get airborne I purchased an Inspire X5 and guess what......
That yoyo's as well, perhaps not as bad as the P4 but i did have higher hopes for a machine that cost 3 times as much as the P4!!!!!!
As I was circling a tower with the auto POI feature it was clearly visible ascending and decending through 1 to 2 metres(3 - 6 feet).
The P4 was far worse as it would pass through 5 to 10 metres which is enough to crash it.
Moral of the story.... you figure it out!

PS. Wish I would have kept the P3 as it flew better than both the P4 and the crappy Inspire1.

Really!! Your still having a drop when you stop your birds at full or any throttle for that matter?? Last firmware upgrade took care of all the drop problems on mine. It's flawless now. Sounds like you are talking about a different issue though if it's dropping as you are flying an auto POI. That's not the same thing as the dropping when coming to stop that the P4's had until the last update. But I did just read about the altitude telemetry from John Locke so I'll have to look at what that's all about. Sorry you are having such bad luck as I am nothing but super happy with my P4 since March.

 

[RémyHeli]

Looks like last firmware cured in some extend the yoyo behavior correctly described by John Locke, but not always completely as mention in DJI firmware notes, and not same for all.

Some wondering if related to specific P4 batches, some dues to flight conditions such as gust wind effect from sudden manoeuver etc. People even tried to mask vent holes to see if any difference (not recommended though).

Some other also arguing would rather go with the software itself but we know depends from hardware and all this technology is extremely complex, as you know.

Just as background if some seing this discussion for the first time.

Hope DJI will be able to debug this and perform proper regression testing as this fiddly issue is impacting P4 flight characteristics and putting at risk under specific conditions (flight style, flight plan, RTH landing excessive speed, etc)

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[gppms]

Problem solved with the latest firmware upgrade.

 

[RémyHeli]

Problem solved with the latest firmware upgrade.

Many reported problem solved but then introducing incorrect altitude readings putting the bird at risk in specific scenarios. Have you noticed your craft showing ie higher altitude than reality?

Thanks for sharing experience.


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[gppms]

Many reported problem solved but then introducing incorrect altitude readings putting the bird at risk in specific scenarios. Have you noticed your craft showing ie higher altitude than reality?

Thanks for sharing experience.


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No after the latest firmware upgrade everything work's perfect.


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[apex1]

I have issues with the altitude sensor being inaccurate at low altitudes, and when I hover several feet off the ground, the p4 slowly drifts down until it lands itself and cuts its motors. I did not have this before the last firmware upgrade. I have calibrated the compass, the IMUs, and the visual positioning sensors using the matrix in the dji assistant, and it still does it. I'm hoping there is a new, better tested firmware update coming soo.

 

[FlashBuddy]

Exactly same by me martybabe,

Beware if RTH in action the craft might descend faster than with previous firmware when performing final approach to the ground as thinking being ie higher than reality. Imagine what's next.. (already discussed in other threads)


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Happened to me [emoji35]

NoCo Drones

 

[RémyHeli]

Thanks for feedbacks.

Note also possible risks with planned flight as based on specific altitudes.

Hope these recommendations will help to keep your bird safe. Thanks all for sharing experience, great forum here.


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[gppms]

Not a single issue like yours.I don't understand what the hell is going on.Mine P4 is the latest version i just bought it,with the old firmware 1,40 something it was very dangerous to fly one day almost to crash on the top of the tree because of the yo yo problem but now everything solved with the latest firmware and the readings of the altitude and distance are accurate.

 

[laserdoc85]

flew mine today and I had the yo yo effect after coming to a stop at about 50 to 60 feet up. Firmware updated 2 weeks ago and compass and IMU also. Will try flying without the gimbal guard this weekend. Was flying over a golf course

 

[Jrods]

Many reported problem solved but then introducing incorrect altitude readings putting the bird at risk in specific scenarios. Have you noticed your craft showing ie higher altitude than reality?

Thanks for sharing experience.


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[Jrods]

Mine shows a negative when I land 75% of the time.

 

[RémyHeli]

Mine shows a negative when I land 75% of the time.

Thanks for feedback Jrods,

It seems there is some common agreement that P4 barometric altitude get´distorted' somewhat while flying. However got impression that's worse than before with latest firmware. Beware in RTH mode craft might descend faster than expected close to the ground as not reducing speed on time. Cancel RTH and finalize manually to secure landing. Also make sure to have some buffer with the altitude if planning flight with Litchi or similar.


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