Question

[Droning on and on...]

Au Contraire Mon Ami… The Mini 2 can and has flown over 100 MPH and here is the YouTube Video to prove it… I'm not recommending it but it is to show it can be and has been done… In fact, under these conditions, it probably was flying backwards at 75 MPH while it was going full speed forward… That's what happens when the headwind is strong enough…

Yes, but not really meaningful to the discussion. Of course if wind exceeds the performance capability of the drone, it will not be able to maintain ground speed.

Heck, a pine 2x4 can fly at 100mph under the right weather conditions. Even better, a car. They're often found blocks away from where they were parked when a tornado comes through town.

 

[Droning on and on...]

Okay, here's the log from yesterday's flight. Once again it confirms everything I've been saying in this thread:

• Ground speed constant flying upwind and down wind
• Average pitch angle much greater flying upwind than downwind. This can mean only one thing: The airspeed flying upwind was greater, by quite a bit, flying upwind vs. downwind. While maintaining ground speed at 21.5±1mph in both directions the entire flight.
• Pitch varying wildly in both directions, indicating highly variable, gusty wind. While holding ground speed, and no fault in the drone, there can be no other conclusion.

 

[@Rip]

I have posted several questions on the DJI forum to address the "Max Wind Resistance" part of this discussion.
Thread Link: Max Wind Resistance (EDIT: Updated link)
My desire was/is to get this link up before the thread is closed for whatever reason.
Hopefully, we will get an acceptable response with answers that benefit all concerned.
Just in case the thread go into an "audit".. Here is the text of my post:

Hello!

I have seen the spec sheet(s) for most Mavic drones and am interested in learning more about "Max Wind Resistance".
Can someone please explain to me a few things on this topic?

• What exactly is "Max Wind Resistance" I use a Mavic2 Pro and am thinking of upgrading...
• How is "Max Wind Resistance" determined for DJI drone systems?
• What criteria is used to determine "Max Wind Resistance"?
• Is "Max Wind Resistance" assigned to a drone after some kind of testing procedure?
• If "Max Wind Resistance" is determined as a result of testing, what kind of tests are performed?
• Is this information available publicly? If so Where can learn more about "Max Wind Resistance"?
• Does "Max Wind Resistance" change under different circumstances?
• How can I apply my knowledge of the "Max Wind Resistance" specification to my safety and flight plans?

I would appreciate any and all information that may shed some light on the "Max Wind Resistance" specification.

I have concerns that "Max Wind Resistance" seems to an ambiguous specification even though implications that it may play a role in Flight Safety or drone tolerances of some sort.

Please advise, as this is important information that may help me be a better, safer pilot.
Thank You
Rip

 

[Meta4]

Okay, here's the log from yesterday's flight. Once again it confirms everything I've been saying in this thread:

• Ground speed constant flying upwind and down wind
• Average pitch angle much greater flying upwind than downwind. This can mean only one thing: The airspeed flying upwind was greater, by quite a bit, flying upwind vs. downwind. While maintaining ground speed at 21.5±1mph in both directions the entire flight.
• Pitch varying wildly in both directions, indicating highly variable, gusty wind. While holding ground speed, and no fault in the drone, there can be no other conclusion.

Thanks for the data, I've not looked closely at up/downwind speed vs tilt before.
It's helped get a better understanding of how it all works.
The flight data gives some insight into how the firmware works to give full speed in varying wind conditions.
I've compared some flight data of my own from a perfectly still day to confirm things.

To move forward, the drone tilts forward.
As it tilts further, it flies faster.

In a car, if you push the accelerator to the floor, the engine goes to, and stays at full speed.
But with current DJI drones when you push the right stick fully forward, the drone doesn't necessarily tilt to the max tilt angle for a given flight mode.

In still air, the drone can achieve max speed without using the max tilt angle and pushing the right stick fully forward results in a tilt angle less than the max for a given flight mode

There is a reserve available to tilt further if the drone is pushing against the wind.
In light winds, the reserve is sufficient for the drone to be able to achieve the full speed shown in the specs by tilting up to the max tilt angle.
If pushing against a stronger wind, max speed can't be achieved even at full tilt.

 

[Meta4]

Flight data showing how the DJI drones have a reserve and don't use full tilt angle unless required to push against the wind

 

[lookout]

Remember when...

You could tilt the pinball machine?

Carry on....

 

[umanbean]

Flight data showing how the DJI drones have a reserve and don't use full tilt angle unless required to push against the wind

Excellent info and table chart.

I don't own any of the '3 gen' machines, but I come here every day and read New Posts anyway - and learn something new about drone behavior in general every single day, but that post is a gem. Thanks for that, and a BIG thanks to @mightypilot2000 for the time and effort to run the test and post the results here!

It's conclusions like this that makes slogging through certain threads worth it! LOL

 

[Droning on and on...]

Thanks for the data, I've not looked closely at up/downwind speed vs tilt before.
It's helped get a better understanding of how it all works.
The flight data gives some insight into how the firmware works to give full speed in varying wind conditions.
I've compared some flight data of my own from a perfectly still day to confirm things.

To move forward, the drone tilts forward.
As it tilts further, it flies faster.

In a car, if you push the accelerator to the floor, the engine goes to, and stays at full speed.
But with current DJI drones when you push the right stick fully forward, the drone doesn't necessarily tilt to the max tilt angle for a given flight mode.

In still air, the drone can achieve max speed without using the max tilt angle and pushing the right stick fully forward results in a tilt angle less than the max for a given flight mode

There is a reserve available to tilt further if the drone is pushing against the wind.
In light winds, the reserve is sufficient for the drone to be able to achieve the full speed shown in the specs by tilting up to the max tilt angle.
If pushing against a stronger wind, max speed can't be achieved even at full tilt.

Since the system logs every 200ms, there's a ton of lines in that file. Anyone that wants to dig deeper into the data, here are some relevant places to look:

• The outbound, upwind N mode leg is lines 700-786. The criteria I used for data selection was reaching spec'd max speed in N, 21mph.
• Inbound downwind lines 860-944.
• The Sport test (same course out and back) is in there too, but I'm not analyzing it.

Summarizing the data for the two Normal mode legs:

Upwind
Avg speed: 21.3mph
Speed range: 19.9 – 22.6
Avg pitch: -27.6°
Pitch range: -18.8° – -30.6°

Downwind
Avg speed: 22.3mph
Speed range: 21.1 – 22.9
Avg pitch: -8.5°
Pitch range: -4.9° – -14.4°

In theory, wind speed could be reasonably approximated by adjusting the "pitch" stick (really the speed control) so that actual pitch is 0°, at which point airspeed should be 0, so whatever horizontal ground speed is displayed should be the speed the air mass is moving over the ground. Gotta be pointed straight downwind for this to work.

Crudely, this may be possible with the pitch/roll indicator in the lower left of the display. Wind direction could possibly be determined by taking off, then hovering in-place and observing the drone while slowly yawing 360°, observing the corrections the FC is doing to hover, until they're exclusively pitch with no roll movements.

When you get as close to that as you can, you're pointed up or downwind. Further observations of stuff moving in the breeze will tell you which.

 

[Droning on and on...]

In still air, the drone can achieve max speed without using the max tilt angle and pushing the right stick fully forward results in a tilt angle less than the max for a given flight mode

There is a reserve available to tilt further if the drone is pushing against the wind.
In light winds, the reserve is sufficient for the drone to be able to achieve the full speed shown in the specs by tilting up to the max tilt angle.
If pushing against a stronger wind, max speed can't be achieved even at full titilt.

Yes, and while DJI is maddeningly opaque about what "max wind resistance" is, we can guess at it, and when we can experiment in conditions where wind is blowing around the max resistance value, make some sense of this parameter on our own.

I'm pretty sure it DOESN'T mean Sport max speed flight into the wind, as my Mini3P was not able to reach 35mph in S flying upwind in what was wind around the max resistance speed, gusting. Best it could do was about 30.

 

[Reelman67]

A few years ago, when I was new to flying my M1P, I came across a situation at Cannon Beach, OR where a guy flew his M1P or M2P, didn't know the difference back then, out over the ocean with a offshore wind. He did his thing out there and didn't allow enough battery life to get back to his launch point. His drone fell into the ocean and later washed ashore after he tried in vain to find it. It was turned into to the local lost and found, a dead drone, where he came the next day to claim it. I posted the fact that it was available at the city, on this forum. Did he have DJI insurance? Highly doubt it.

 

[@Rip]

Here is my initial (unaltered) response from DJI Mavic 2 Pro forum "Captain".

Even if the definition/s is/are given of what use will it/they be to you?

The wind speed you see at ground level is unlikely to reflect the wind speed at height, wind speed generally increases with height.
What you should be interested in is seeing if
a) the drone can hold position in a hover in wind at the chosen height. There is, in effect, an artificial-horizon/attitude-indicator in the Go4 app that indicates the drone's tilt. As such the tilt will indicate the strength of the wind that the drone is having to fight to hold a hover, that idea extends into commanded horizontal movement as well. I.e. if the tilt is not appropriate to the commanded ground speed then the drone is in wind e.g. if the drone is flying horizontally yet the artifical horizon is showing the drone is horizontal it, the artificial horizon, is telling you that the drone is being flown downwind in a wind whose speed matches the commanded ground speed.b) With each flight mode, including RTH, what headway, speed wise, it can make into a head wind?

You DO NOT want the drone fighting a headwind that slows a return to home journey to 1 or 2 metres per second ESPECIALLY if the return trip is a long ground distance. With regards to flying horizontally

 

[Droning on and on...]

Rip, I don't find anything helpful in that reply at all. It was unresponsive to the question.

Personally, I take a rather dim view toward making an answer to a question conditioned upon you defending why you're asking it.

Thanks for sharing this.

 

[@Rip]

Rip, I don't find anything helpful in that reply at all. It was unresponsive to the question.

Personally, I take a rather dim view toward making an answer to a question conditioned upon you defending why you're asking it.

Thanks for sharing this.

He did not answer anything. And the "What's it to you" response was a bit disconcerting. The thread is still open so I am pondering if and how I may reply. And if it is even worth the time.

 

[Sam36401]

He did not answer anything. And the "What's it to you" response was a bit disconcerting. The thread is still open so I am pondering if and how I may reply. And if it is even worth the time.

My only advice is this:

“Never argue with a fool, onlookers may not be able to tell the difference.”
​

― Mark Twain

 

[Meta4]

Here is my initial (unaltered) response from DJI Mavic 2 Pro forum "Captain".

It looks like the moderators over there have ignored your thread.
The only response you had was from a forum member.

 

[mobilehomer]

You misread Sean's reply. It's not just "What's it to you", he qualified it with specifics. DJI only tests at certain altitudes and conditions. Their claims have little to no corelation to your conditions. Unless DJI releases their testing parameters, all anyone can do is guess.

 

[lookout]

You misread Sean's reply. It's not just "What's it to you", he qualified it with specifics. DJI only tests at certain altitudes and conditions. Their claims have little to no corelation to your conditions. Unless DJI releases their testing parameters, all anyone can do is guess.

Those numbers in the wind tunnel where the drone was strapped down with a 5 point restraint, didn't you know those were the testing conditions?

 

[Meta4]

Here is my initial (unaltered) response from DJI Mavic 2 Pro forum "Captain".

One of their moderators has replied.
Unfortunately the "answer" is meaningless mumbo-jumbo and doesn't answer what was asked.

 

[@Rip]

One of their moderators has replied.
Unfortunately the "answer" is meaningless mumbo-jumbo and doesn't answer what was asked.

Well you warned us! I have made a last attempt.

 

[@Rip]

So the thread on DJI forum is expanding somewhat:

For DJI drones, the max wind resistance isn't the point of failure, but the limit at which the drone will not be able to tilt into the wind and fight it to remain in place. What DJI does implement, which is clever, is that the drone will drift with the wind if it exceeds the max wind speed. Not ideal, but also better than the drone tilting over and falling from the sky. So the max wind speed DJI quotes is really the 'SWL' point in which the drone will give up and just move with the wind. Obviously if you're in a hurricane it's not going to sustain flight, but there is a margin of error and protections in place.

What I would suggest is to take DJI's max wind resistance, knock 20-25% off that speed and (if you're a commercial operator) state that is the max wind resistance you'll fly in and it can be verified before takeoff using an anemometer.

Also, keep in mind that DJI also states a maximum surface takeoff wind, which is usually a third of the max wind speed.