I had mine drop from about 1 to 1 1/2 feet over land today with no input at all. I was flying about 20 mph. The problem is, I'm preparing for some water flights at that altitude, if you want to call it that. No chance of catching mine. Thinking about raising my altitude a little.
Visual positioning and barometer while flying above water
- Thread starter afarkas
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I had mine drop from about 1 to 1 1/2 feet over land today with no input at all. I was flying about 20 mph. The problem is, I'm preparing for some water flights at that altitude, if you want to call it that. No chance of catching mine. Thinking about raising my altitude a little.
Turn11
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Timmavic
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Thanks for the response afarkas,I only use go4 so don’t think that’s the issue, I have had it happen over gin clear water as well as murky and muddy water both fresh and salt luckily caught it every time before the inevitable swimming lesson!!
Hallo from Germany , i am new in this Forum and Me English is Not the best, nur read your Problem and i thing we habe the same.
Problem Mavic2Pro permanently sinks in a straight flight over a frozen pond.
My incident:
Start success from a table (about 1 m above ground) the frozen pond surface (about 1/2 m lower than ground). In straight flight (starting height approx. 1 m above ground), the Mavic2Pro permanently loses altitude. After about 100 m the Mavic2Pro had only about 20 cm height above the ice surface. With hovering, hovering automatically took place on the ice with automatic shutdown of the engines.
My guess: due to the overall low altitude, the drone remains in automatic landing mode, with the tax sticks known to remain active. Thus, even in the straight flight (manually, via stick) a landing "sink" flight is executed. If now the flight (Hover'n) is interrupted, the water landing is automatically executed immediately (luck, if water is frozen).
The onward flight leads to an uncontrolled accident.
Could that be your problem too ?!
Best Regards from Germany...
Mossiback
Well-Known Member
Bobby Brown
Well-Known Member
No, i do not think it is caused by "automatic landing".
The problem you describe can be caused also by the 1 - grounds elevation or 2 - as the craft is tilted down the air aerodynamics is pushing the craft down as it accelerates and the precision of GPS altitude measuring is not fine enough to notice 1 meter descent...
Me myself noticed that flying fast near to ground causes approaching to the ground, but with naked eye you cant see 3% elevation of the ground, but those 3% on 100 meters make 3 meters...
The problem you describe can be caused also by the 1 - grounds elevation or 2 - as the craft is tilted down the air aerodynamics is pushing the craft down as it accelerates and the precision of GPS altitude measuring is not fine enough to notice 1 meter descent...
Me myself noticed that flying fast near to ground causes approaching to the ground, but with naked eye you cant see 3% elevation of the ground, but those 3% on 100 meters make 3 meters...
conchman
Well-Known Member
I fly over water all the time and its never happened to me. I will watch for this from now on, though.
Battery temperature about 15 C. And 90% charge. Warm up (hover) approx. 2 min.
Outdoor temperature approx. -2 C.
A Drone doesn’t know it’s over water. I’ve never had a issue and live on a large Lake
I agree with that.
Only the calm water ensures that it has 100% no inclines. As proof that the drone really falls unintentionally.
The "why" does not seem to be clear yet.
I agree with the opinion.
Only the "why" drops the drone remains unclear!
The fact is, there is no incline over calm water and thus the drone should never approach the water surface unintentionally.
So where is the problem?
DJI?
That is unbelievable.
Can you tell us more details?
How high have you flown over the water?
Hovern at this altitude ???
(Caution "automatic water landing possible!)
And the altitude also never corrected manually during the water flight?
In which modes did you fly?
Which sensors were active?
And then the ambient temperature ??
Do you have your own hint or suspicion ??
Maybe i wasnt clear enough.
The drone should not descent if howering.
But if accelerating, the drone itself is inclined forward and the aerodynamics pushes him down.
Maybe he just does not reacts fast enough to compensate the descent, maybe a descent of 50cm is not enough to trigger the comoensation...
The drone should not descent if howering.
But if accelerating, the drone itself is inclined forward and the aerodynamics pushes him down.
Maybe he just does not reacts fast enough to compensate the descent, maybe a descent of 50cm is not enough to trigger the comoensation...
Hi Mavic 2018,
Answers to your question:
As low as 3-4 ft
Yes, I have hovered, although briefly.
No observable corrections.
I fly mostly in P mode although I flew tripod once.
Normal front back and down sensors for P mode, and all normal for Tripod
Ambient temperature varies, but probably 50 - 70 deg F
Hint or suspicion of what?
Ken
Hi, Afarkas,
Sorry for being late.
I read that in the DJI forum
also users with this problem exist.
Get in contact with DJI Support now.
Let's see what DJI writes about it.
Thanks again for your opinion / explanation on this topic.
Mavic-2018
Hi Ken,
thank you for your information for my problem.
I have informed DJI now and expect an answer.
Will my Mavic2Pro recalibrate again and test again.
Mavic 2018
kilomikebravo
Well-Known Member
Someone please correct me if this logic is FUBAR'd but I believe the only reason the aircraft pitches forward when accelerating is to prevent it from CLIMBING when power is increased.
I'm not really qualified to answer this, I'm not an aerospace engineer but did sleep at a holiday inn last year. This is my thinking. Whether accelerating or traveling at a set speed, the aircraft does pitch forward for that purpose. I think that is to build or continue forward speed. At the same time, the tilt of the aircraft should cause a down force, created by traveling at speed, on the top front, rear of the aircraft. And, at the same time, the bottom sensors and barometer are trying to keep the aircraft at the required altitude having to increase or decrease the power at the props to attain that. Then you have the tolerances of the sensors, or any of the electronics, altitude, wind speed and direction, which then throws other problems/possibilities into the mix. While your logic is not FUBAR'd there are many other things that have to be considered. I'm trying to figure out whether to try flying over water at around 1 to 2 feet and found during my first land test that the M2P will dive straight into the ground at that altitude, at least once.
I agree with your logic, the afarkas supposition is incomplete. The aircraft pitches forward to go forward. It pitches just enough to go forward at the requested speed/acceleration without climbing or descending. This assumes that the only control input is right stick forward (mode2).
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