Question

[Droning on and on...]

Thanks for keeping us in the loop, Rip!

Sorry for the length...

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.

Many (most?) of us would consider that the "point of failure".

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.

What?!??

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.

All 100% wrong. I've proven this empirically, comparing actual behavior and performance to the "Wind Resistance" specification for the Mini3P.

Summary: We don't know what DJI means by "Max Wind Resistance". From actual operation, behavior, and performance, however, we can infer with some confidence that it at least means the max wind speed the drone can fly directly into and still make decent forward progress, able to return to the Home Point (battery charge permitting). Read on for the details.

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We have no idea how DJI measures or computes "Wind Resistance". What I can say with certainty is it is not the max wind speed that can hold a hover, in which case no forward flight directly into the wind is possible.

The Mini3P, and presumably all DJI drones can fly faster through the air at max tilt than their specified max ground speed, which is what the Flight Controller targets – ground speed. We do not have a Pitot Tube or other means to sense airspeed... The FC has only ground speed values derived from GPS and the VPS system.

At max tilt, based on flight log data, It looks like the Mini3P has a max airspeed around 40mph. This leaves a 5mph margin to fly directly into the wind in Sport mode and still achieve max ground speed at 35mph.

Flying directly into an estimated 10mph wind in Sport the Mini3P topped out at ~30mph.

With this real data, the 3P could theoretically hold position in a 40mph wind. By DJI Forum Jaboney's theory, "Max Wind Resistance" would therefore be about 18m/s.

The spec, however, says 10.7m/s. At that wind speed, the Mini3P has an additional 7m/s or about 15mph "headroom" against the wind to make it back.

IOW, testing shows that "Max Wind Resistance" could mean max headwind that allows for 15mph progress over the ground.

There's no guesswork here. These are all measured values in real flight on a moderately windy day. The only caveat is these are all estimated values based on using Beaufort Scale observations to estimate wind speed. All other values carry the precision of Flight Log values.

 

[Meta4]

IOW, testing shows that "Max Wind Resistance" could mean max headwind that allows for 15mph progress over the ground.

I was flying today next to another pro who was flying an Inspire 2.
Oddly DJI gives a Max Wind Resistance for the Inspire 2 of 10 metres/sec (about the same as for your Mini 3 pro).
How can that be when the Inspire 3 has a Max Airspeed of 26 m/s, or 62% more than the Max Airspeed of your Mini 3 (16 m/s) ?

 

[Droning on and on...]

I was flying today next to another pro who was flying an Inspire 2.
Oddly DJI gives a Max Wind Resistance for the Inspire 2 of 10 metres/sec (about the same as for your Mini 3 pro).
How can that be when the Inspire 3 has a Max Airspeed of 26 m/s, or 62% more than the Max Airspeed of your Mini 3 (16 m/s) ?

Where did you get the max airspeed figure for the Inspire? You also mention max airspeed for the Mini3P which I don't know, other than a guesstimate based on the testing I did.

In any case for the sake of this response I'll assume you meant ground speed. Keep in mind the max ground speed is a configured parameter, not a performance limit. It's not based on configured pitch angle limits, which, in still air would fly a fair bit faster over the ground if the Flight Controller allowed it.

Regardless, my specific analysis applies only to the Mini3P.

The most accurate statement I can make regarding the numbers you provide above is that's how DJI configured it.

If I were to make a general speculative statement that would apply to the Inspire too, I'd simply say, "'Max Wind Resistance' could mean max headwind that allows for meaningful progress over the ground."

Concept is that you can reasonably and effectively get home. To make sure nothing is misunderstood, this is a characterization of observed and measured behavior with the Mini3P, however every DJI drone I've owned has behaved identically.

I put a word in bold there to make sure it doesn't get missed.

 

[lookout]

I took it to be about 20 mph. I was flying with about that much wind near the surface. It took a gust that I think pushed the drone forward but otherwise it was holding steady in hover.

 

[Meta4]

Where did you get the max airspeed figure for the Inspire? You also mention max airspeed for the Mini3P which I don't know, other than a guesstimate based on the testing I did.

In any case for the sake of this response I'll assume you meant ground speed. Keep in mind the max ground speed is a configured parameter, not a performance limit. It's not based on configured pitch angle limits, which, in still air would fly a fair bit faster over the ground if the Flight Controller allowed it.

Regardless, my specific analysis applies only to the Mini3P.

It's there in the specs for every DJI drone.
But since you cannot understand the extremely basic concept of what Max Airspeed is, you'll never understand any of the details of how your drone interacts with wind.

If I were to make a general speculative statement that would apply to the Inspire too, I'd simply say, "'Max Wind Resistance' could mean max headwind that allows for meaningful progress over the ground."

Concept is that you can reasonably and effectively get home. To make sure nothing is misunderstood, this is a characterization of observed and measured behavior with the Mini3P, however every DJI drone I've owned has behaved identically.

The maximum headwind speed that allows the drone to make "meaningful" progress ???
Apart from that being such a vague concept and completely meaningless to users, the example from the Inspire 2 specs shows it can't possibly be correct.
Under your guessed definition, the I2 has a max airspeed of 26 m/s, but couldn't make meaningful progress against a headwind of only 10 m/s ???

 

[umanbean]

Thanks to everyone for the chuckles. These 'what's the fastest wind speed I can fly in' threads are always entertaining.... lol

 

[Droning on and on...]

It's there in the specs for every DJI drone.

I say it's not. Prove me wrong. Cite the manual and page for any DJI drone where max  airspeed is specified.

Here's the spec from the Inspire 3:

Max Horizontal Speed 94 kph​

Measured when flying in a windless environment at sea level, with gimbal camera and lens attached to the aircraft and without other accessories. This data is for reference only.​

That's a ground speed measurement.

But since you cannot understand the extremely basic concept of what Max Airspeed is, you'll never understand any of the details of how your drone interacts with wind.

Back with the insults, I see

 

[umanbean]

I use two ancient and tried-and-true methods to determine wind speed and direction at the ground.

I stick my index finger in my mouth and wet it, then hold it vertical in front of me. Whichever side is the coolest, that's the direction the wind is coming from.

And if I hold my bandana by a corner in front of me and it stands out straight horizontally, wind's too strong to take off.

There, that settles that.

 

[LoudThunder]

I hold my bandana by a corner in front of me and it stands out straight, wind's too strong to take off.

 

[umanbean]

BTW, there are 4 types of airspeed-

groundspeed
true airspeed
indicated airspeed (IAS)
calibrated airspeed (CAS)

Remind me again, which one is being argued here?

 

[umanbean]

Back with the insults, I see

A classic case of the pot calling the kettle black.

 

[lookout]

I use two ancient and tried-and-true methods to determine wind speed and direction at the ground.

I stick my index finger in my mouth and wet it, then hold it vertical in front of me. Whichever side is the coolest, that's the direction the wind is coming from.

And if I hold my bandana by a corner in front of me and it stands out straight horizontally, wind's too strong to take off.

There, that settles that.

If the flag is straight out that's 15mph or better.

 

[@Rip]

So here’s my example for today really really windy on the beach. The drone was listing heavily, but it did not move . I was able to do some quick shots and other cool things with the drone even though the wind warnings never ceased . By the time I actually tested, RTH …. water had covered the spot where I took off, so I was unable to land at the home point.

 

[@Rip]

So please notice the drone is listing and this is not the maximum angle, but it’s what we caught on camera, the gimbal is absolutely level with the horizon.

 

[umanbean]

The drone was listing heavily, but it did not move .

Maybe the wind didn't exceed the Maximum Wind Resistance spec? lol

That screenshot looks a lot like Go4, either the Fly app has happily evolved quite a bit or you were flying one of the Oldie-but-Goodies (like me)

 

[Meta4]

I say it's not. Prove me wrong. Cite the manual and page for any DJI drone where max  airspeed is specified.

Here's the spec from the Inspire 3:

Max Horizontal Speed 94 kph​

Measured when flying in a windless environment at sea level, with gimbal camera and lens attached to the aircraft and without other accessories. This data is for reference only.​

That's a ground speed measurement.

DJI state the Max Speed for the drone in still air.
Airspeed is the speed of an aircraft relative to the air it's passing through.

(Now comes the really simple part that you cannot get your head around)
The fastest the drone can fly is given to you by DJI.
The drone cannot fly faster than that.
Those max speeds are when the air is still.
That means that the speed of the drone relative to the (still ) air is the given value.
And as the air is still, that is also the drone's groundspeed.

If you doubt this, look back at the data I gave earlier for a flight in still air.
The groundspeed achieved = DJI's max Speed in still air.
That can be achieved at less than full tilt, or if flying against the wind more tilt will be used to go faster.
But the drone won't tilt further than DJI's max tilt angle.

If the air is moving,, the groundspeed could be less than max, but because of the way DJI program their drones, groundspeed won't be more than max speed (unless the wind is so strong that it overcomes DJI's speed limiting)

Despite all your protesting, In a nutshell, Max Airspeed equals DJI's stated Max Speed in still air.

Back with the insults, I see

It's not throwing insults to point out that you are wrong.

 

[@Rip]

Let's leave the insults out of the discussion if possible. The discussion is apparently still on with DJI...

 

[@Rip]

@rip asked specific and very good questions.
Unfortunately your reply didn't answer any of them.
Are you able to find someone at DJI who can?
(Dji)
We are sorry to inform you that there is no more information about that. Could you kindly tell us what problems did you encounter during use? And we can help you solve it.

So the answers are hidden, Convoluted. My earlier posts should say it all. DJI does not want to share how the tests were done. It s OK with me.
My response:

Thank you for attempting to get more information on this.
I am not having any issues with my drone or ability to pilot the craft.
The reason for the questions is for my own education and edification, to satisfy my own curiosity about Max Wind Resistance and what it means.

Why even post Max Wind Resistance stats if they mean nothing in the first place. "There is a number, but if I tell you.... "

All I am asking is how the tests are performed to achieve the specification. (Not to steal propitiatory information)

I fly in the wind. That is where I am at. I just cant rely on "specs" to do it.
I am done with this question to DJI.

 

[@Rip]

Maybe the wind didn't exceed the Maximum Wind Resistance spec? lol

That screenshot looks a lot like Go4, either the Fly app has happily evolved quite a bit or you were flying one of the Oldie-but-Goodies (like me)

It was mostly gusts. According to my weather sensor 26 MPH gusts. That's all. I'll do it again tomorrow.

 

[LoudThunder]

I use the Windy.com App on my Android devices. Here is an earlier posting I did on it. It might save you a wasted trip only to find out that the wind is too strong or gusty at your proposed spot…

This is the link to it...

a tiny flying tip