I think those numbers in the spec apply when the craft is in normal state. When the craft is in an anxious state, it will act more aggressively. This was my Mini flying under a yaw error of 180 degrees in P mode. It banked so hard that the gimbal could not keep up. This will never happen in normal flying :
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I think those numbers in the spec apply when the craft is in normal state. When the craft is in an anxious state, it will act more aggressively. This was my Mini flying under a yaw error of 180 degrees in P mode. It banked so hard that the gimbal could not keep up. This will never happen in normal flying :
There is no such thing as aground speed governor. The only speed restriction is a result of the tilt angle limit in the drone flight control software. The drone tilts to move in any direction. The more tilt, the more speed.
However, the more tilt, splitting the motor force between horizontal movement and maintaining altitude, the more net force required. Eventually the motor battery combo cannot provide it. The tilt angle limit prevents the drone from ever reaching this state.
With this in mind, the horizontal velocity spec for the drone is directly linked to this angular limit in STILL AIR. If there is any wind present, the speed over ground will be different, the vector addition of the wind direction and velocity, and the drone’s direction and velocity.
However, the more tilt, splitting the motor force between horizontal movement and maintaining altitude, the more net force required. Eventually the motor battery combo cannot provide it. The tilt angle limit prevents the drone from ever reaching this state.
With this in mind, the horizontal velocity spec for the drone is directly linked to this angular limit in STILL AIR. If there is any wind present, the speed over ground will be different, the vector addition of the wind direction and velocity, and the drone’s direction and velocity.
To Dave Maine, just to ensure I am understanding you correctly, are you saying that a DJI drone can, with respect to the ground, exceed, by a significant and sustained amount, the stated maximum speed if flying down wind?
That is contrary to my experience which is, that a headwind may reduce the achievable ground speed but a tailwind will not increase the sustained maximim ground speed beyond the DJI specified maximum "speed". Yes I have seen momentary instances of 'excess speed' but not a sustained excess. This is why this reported 67mph struck me as startling.
As such it is my belief that the operating system alters the permissable tilt such that the ground speed is "governed".
Obviously I will stand correction on this.
That is contrary to my experience which is, that a headwind may reduce the achievable ground speed but a tailwind will not increase the sustained maximim ground speed beyond the DJI specified maximum "speed". Yes I have seen momentary instances of 'excess speed' but not a sustained excess. This is why this reported 67mph struck me as startling.
As such it is my belief that the operating system alters the permissable tilt such that the ground speed is "governed".
Obviously I will stand correction on this.
Which operating system are you talking about? The phone/tablet? The rc? The drone itself?
The only os that could possibly do this is the drone SW. As far as I have read, it only monitors tilt angle, and has a fixed angular limit. This is consistent with the physics required to keep the drone in safe flight. It is certainly possible in software to modify that limit downward to set a top speed limit over ground. It would require creating a feedback loop from the flight system controller, and feeding the derived data back into the tilt angle motor control circuits.
Having said that it is possible, why would DJI want to add that complexity and potential error source into what is an already extremely complex real time system? I don’t see any real advantages from doing this. Without reading the DJI source code, there is no way to know definitively what is really going on.
The only os that could possibly do this is the drone SW. As far as I have read, it only monitors tilt angle, and has a fixed angular limit. This is consistent with the physics required to keep the drone in safe flight. It is certainly possible in software to modify that limit downward to set a top speed limit over ground. It would require creating a feedback loop from the flight system controller, and feeding the derived data back into the tilt angle motor control circuits.
Having said that it is possible, why would DJI want to add that complexity and potential error source into what is an already extremely complex real time system? I don’t see any real advantages from doing this. Without reading the DJI source code, there is no way to know definitively what is really going on.
The drone's.
OK, a simple question, in terms of the speed indicated in the app have you seen a drone, in normal flight, significanlty exceed the stated maximum speed for a sustained period of time whilst flying down wind?
I have never tested it. If the data you have proves repeatable, then something is going on for sure. What that would be will be buried deep in the flight control system software, which, asI have said before, is proprietary toDJI.
Consider on of the most basic statistics guidelines “correlation is not causation”. We simply don’t know what is going on. SAR104 has a fine posting analyzing how the flight control system actually works. This would be a good starting point for looking into to what could be going on.
Consider on of the most basic statistics guidelines “correlation is not causation”. We simply don’t know what is going on. SAR104 has a fine posting analyzing how the flight control system actually works. This would be a good starting point for looking into to what could be going on.
On a different matter, is the txt flight log in post 9 of this thread wonky?
On my PC CsvView 4.0.4 doesn't like it and nor does Phantompilots logviewer and I get the same results of I try CsvView on the txt file fro Airdata
On my PC CsvView 4.0.4 doesn't like it and nor does Phantompilots logviewer and I get the same results of I try CsvView on the txt file fro Airdata
Kilrah
Well-Known Member
That's completely wrong for all DJI aircraft in GPS mode for more than the past 5 years. You're describing ATTI mode but that hasn't been available on pilot command for quite a while.
Stick center means 0 ground speed (hold position), full stick means a certain preset groundspeed in that direction that depends on the model. If you hold the stick mid way forward and that corresponds to 8m/s on that model it will fly 8m/s straight forward regardless of wind and compensate in any way required to achieve that speed and direction as long as it's not hitting the max tilt limit.
It's wonky in the sense that it's a new encoding scheme being used by DJI. I expect that we will be seeing more of these as pilots install the newer versions of the Go and Fly app.
Does that mean it is encrypted and you will not be able to work your magic or do I need the new version of CsvView.?
Sorry, I'm out of tricks. CsvView doesn't actually do the the conversion. Rather TXTlogToCSVtool is used for the conversion. You can follow the efforts to upgrade TXTlogToCSVtool to handle the new encoding scheme here
[TOOL][WIN] Offline TXT FlightRecord to CSV Converter
Guess that rules out up dates for me then lol.
Sassin Frassin 'Richard' Dastardly (NOT at BudWalker BTW)
Sassin Frassin 'Richard' Dastardly (NOT at BudWalker BTW)
I concur. It is true that tilt angle is limited which would limit speed in still air with no wind through headwind.
But GPS can, and I am sure does get used to limit ground speed when you have a tail wind. It makes perfect sense. Tilt angle isn't limited here, since with a tail wind, you don't need as much tilt to achieve the same speed.
And there would be a very good reason to limit ground speed: safety, particularly when many of the models can go quite fast in still wind in normal mode, let alone sport mode. I don't think it's wise or safe to allow our Mavics to go over 60mph even if it's achieved by a tail wind.
Hi I am sending it back to DJI but do I just send the drone or everything i.e. RC, battery's and charger.
Thanks
Thanks
I had a different drone fly away at 65mph according to the telemetry once. Had some kind of IMU failure or something mid-flight that introduced a yaw error over the Mississippi River. Needless to say I didn't get that one back...
DJI limits the tilt angle for different flight modes but they also limit groundspeed.
From about five years ago, DJI implemented GPS braking to keep groundspeed to close to the max speed in the specs, even with a tailwind.
With a very strong tailwind, it's only possible to go a little faster.
Even at full stick the drone will tilt less than it would in still air or pushing against a headwind.
But if GPS is not acting on the drone's speed (you are flying in atti mode), you can achieve much greater tailwind speeds.
Try it yourself and you'll see that you get very little speed boost flying with a tailwind.
Robyhe
Well-Known Member
I've just recently received my mini 2 as a Christmas gift (happy as hell) flown it once and have noticed it tends to creep in reverse even when not touching the controls so I'm hoping this isn't the same problem your experiencing. Currently using Galaxy S9+ whichever had to be updated anyway.
I did find the M2 was very responsive though and I must admit I'd received wind warning when this drifting took place.
Well DJI have got back to me to say that with me being in the UK lockdown policy implemented by public health authorities in Britain and Ireland, standard package delivery service has been temporarily suspended, express service is expected to be delayed.
So I had a check on the drones condition and looking at it the props have took the damage as it crashed into the trees and did not hit the ground. So I replaced all the props and on a level surface checked with a spirit level calibrated IMU and Compass.
As the weather is crap outside, I give indoors ago, let it hover for 5 minutes and it kept level and done all the movements with no problem. The Gimbal and camera both worked. Have changed mobiles from a Samsung s6 to Google pixel 4a with airplane mode on. Before I take it outside to give it a little go is there anything else I should look for.
So I had a check on the drones condition and looking at it the props have took the damage as it crashed into the trees and did not hit the ground. So I replaced all the props and on a level surface checked with a spirit level calibrated IMU and Compass.
As the weather is crap outside, I give indoors ago, let it hover for 5 minutes and it kept level and done all the movements with no problem. The Gimbal and camera both worked. Have changed mobiles from a Samsung s6 to Google pixel 4a with airplane mode on. Before I take it outside to give it a little go is there anything else I should look for.
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Man, I didn’t realize all of this data gets stored automatically. It makes me feel a little more comfortable flying!
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