Scary experience tonight, Lesson learned?

[meeestermike]

The photo in post #32. Ferromagnetic iron in the steel rebar.

A short explanation of compass function, calibration and errors.

Thank you very much for the information!!!

 

[slup]

...I am sure though the yaw could be off a few degrees and no one would be the wiser and that is because a visual observation of a screenshot would not be highly accurate.

In order to establish if you have a wrongly initialized IMU coming from a magnetically deflected compass when you power on your craft you compare the map drone icon direction with reality ... if you have a yaw error, the deviation will not be just some degrees hard to judge ... it will be hard to miss, well over a 30 degree deviation.

If the deviation is near/around 90 degrees your craft will speed up well over your crafts speed specification & fly away uncontrollably in an arc shaped flight path. If instead wrong by a half turn it will give it all in a straight path.

It seems as you aren't especially interested to get to the bottom with your incident or learn ... instead trying to minimize the risks associated with launching from reinforced concrete balcony's. Have during the years seen numerous of yaw error incidents where a balcony have been the launch spot ... all have claimed that they have used their balcony several times before the incident without a problem ... until they had the bad luck to power on the craft just where the steel reinforcement mesh crosses or is closest to the concrete surface.

 

[Mantrain]

again, there is n discernable deviation. the craft became uncontrollable about three feet outside of the balcony though. I believe it was the low light conditions and the bypass mode.

But you can be sure if I ever have a mishap again, mavicpilots.com will be the last place I post about it. This is not a place to learn and exchange experiences but rathe to be bashed by other members. This forum is really kind of sucky that way and I am sure discourages others to relate their experiences.

 

[sar104]

again, there is n discernable deviation. the craft became uncontrollable about three feet outside of the balcony though. I believe it was the low light conditions and the bypass mode.

But you can be sure if I ever have a mishap again, mavicpilots.com will be the last place I post about it. This is not a place to learn and exchange experiences but rathe to be bashed by other members. This forum is really kind of sucky that way and I am sure discourages others to relate their experiences.

It's unfortunate that you feel that way, but this was entirely self-inflicted. You came here with a report of an incident completely lacking in detail, and then proceeded to ignore all the knowledgeable advice on what most likely caused the event, instead choosing to rely on simple correlation to explain it. And it wasn't the first time either - you turned your previous thread about a failed RTH into a frustrating mess. If you don't actually want any help then it's very simple - just stop encouraging people to respond to your incorrect assumptions by not posting them.

 

[Paradigm]

The speeds shown in the specs are exactly the same as for the Mavic 2.
15 m/s (N mode) 19 m/s (S mode)

M3 is quicker. Perhaps max speed is the same, which I doubt, it gets there much faster. It increases/decreases height at 2x the speed, as well.

 

[sar104]

M3 is quicker. Perhaps max speed is the same, which I doubt, it gets there much faster. It increases/decreases height at 2x the speed, as well.

Why do you doubt it - all you have to do is look at the aircraft specifications. In S mode the M2P maximum speed is 20 m/s, and the M3 is 19 m/s. The M3 does climb and descend faster, but that's clearly not what you were referring to in post #8.

 

[RocketBrew]

Is the 47.2 mph (21.1 m/s) maximum speed reported by the aircraft, or is that an Airdata message?

M3 is quicker. Perhaps max speed is the same, which I doubt, it gets there much faster. It increases/decreases height at 2x the speed, as well.

The speeds shown in the specs are exactly the same as for the Mavic 2.
15 m/s (N mode) 19 m/s (S mode)

 

[sar104]

Is the 47.2 mph (21.1 m/s) maximum speed reported by the aircraft, or is that an Airdata message?

View attachment 140417

It's an aircraft message.

 

[Meta4]

This is not a place to learn and exchange experiences but rather to be bashed by other members.

On the contrary, you have that backwards.
Mavicpilots is a collaborative process where flyers learn by sharing experiences.
The only way to find out what causes flight incidents is analysis of the recorded flight data.
Flyers who share data from their incidents benefit by learning what caused their incident and how to prevent it in future.
If their drone was lost, the location where it came down is often found.
All members learn from incident reports to improve their flight safety.
And the data wranglers, become better at their craft from seeing a wider range of what can go wrong.

There is a great body of drone flying knowledge here that everyone benefits from and it came to be that way by sharing flight data.

 

[Paradigm]

Why do you doubt it - all you have to do is look at the aircraft specifications. In S mode the M2P maximum speed is 20 m/s, and the M3 is 19 m/s. The M3 does climb and descend faster, but that's clearly not what you were referring to in post #8.

There is a difference between max speed and acceleration, which I mentioned in my last posts.

What are the acceleration rates?

 

[Paradigm]

DJI Mavic 3 vs DJI Mavic 2 Pro Comparison

DJI launch the Mavic 3. See how it compares to the previous generation Mavic 2 Pro, as well as other DJI camera drones, such as the Air 2S.

www.heliguy.com

Not sure how accurate that is, but it states it's a little faster. Also says it's 35% more aerodynamic, which leads me to believe it does indeed accelerate faster than the M2P.

So top speed and acceleration is better?

 

[sar104]

There is a difference between max speed and acceleration, which I mentioned in my last posts.

What are the acceleration rates?

The adjective "fast" means high speed, not acceleration.

Acceleration is not specified, but is a direct function of tilt angle if mass and drag are similar, which they are for the M2 and M3. They also have the same maximum tilt angle in sport mode (35°), and so the maximum horizontal component of thrust, and therefore maximum acceleration, should be the same.

DJI Mavic 3 vs DJI Mavic 2 Pro Comparison

DJI launch the Mavic 3. See how it compares to the previous generation Mavic 2 Pro, as well as other DJI camera drones, such as the Air 2S.

www.heliguy.com

Not sure how accurate that is, but it states it's a little faster. Also says it's 35% more aerodynamic, which leads me to believe it does indeed accelerate faster than the M2P.

So top speed and acceleration is better?

Not sure where he got the 21 m/s for the M3 - the official DJI specification is 19 m/s. Marginal difference either way. 35% less drag would mean higher acceleration as speed increases since the instantaneous acceleration is (horizontal thrust - drag) divided by mass.

 

[RocketBrew]

I have recorded 47.2 mph (21.1 m/s) maximum speed. It seems the actual maximun speed allowed in firmware is higher than the published specification.

Not sure where he got the 21 m/s for the M3 - the official DJI specification is 19 m/s. Marginal difference either way. 35% less drag would mean higher acceleration as speed increases since the instantaneous acceleration is (horizontal thrust - drag) divided by mass.

 

[slup]

I have recorded 47.2 mph (21.1 m/s) maximum speed. It seems the actual maximun speed allowed in firmware is higher than the published specification.

View attachment 140450

That shorter moment of higher speed doesn't mean much & don't tell us that the software allows higher speeds than what's stated in the specs.

Have seen this from nearly all DJI crafts ... & it usually occurs when the craft flies at full speed with a near direct gusty tailwind making the craft not utilizing max tilt angle, instead it goes back & forth between more or less tilt angle to either brake or accelerate. If the tailwind suddenly gets stronger it takes some time for the tilt angle to let off for braking & at the same time modulate the motor rpm to keep a steady altitude ... this can momentarily give 1-2m/s extra but only during a rather short period.

 

[slup]

M3 is quicker. Perhaps max speed is the same, which I doubt, it gets there much faster...

And you have compared this with the same stick sensitivity & EXP settings..?

The acceleration can vastly be altered by adjusting these 2 settings without lower the max speed. The M2 have in it's GO4 app always had the possibility to modulate those settings & even the default was much softer than the twitchy M3. The M3 with it's Fly app on the other hand have only lately got the possibility to set EXP.

 

[Paradigm]

The adjective "fast" means high speed, not acceleration.

Acceleration is not specified, but is a direct function of tilt angle if mass and drag are similar, which they are for the M2 and M3. They also have the same maximum tilt angle in sport mode (35°), and so the maximum horizontal component of thrust, and therefore maximum acceleration, should be the same.

I think you're perhaps being overly pedantic with fast specifically used to refer to top speed vs acceleration. But I still think it is quicker and faster than the M2P.

In terms of tilt angle, I imagine just like with FPV, the prop size/angle matters and so does the motor. Are props/motor rpm equal between them?

I also don't 100% trust the advertised numbers. And let's be honest, DJI doesn't have the best record with such things. But I will say, it's a good starting point.

@slup I did think of stick rates when I was making my previous posts. I don't have them altered and they are set at their default for both drones.

I'll try to fly both back to back again and try to narrow down and normalize some of the variables. I recommend you guys do the same to see if you see a difference in how fast and quick they are.

 

[Meta4]

I also don't 100% trust the advertised numbers.

It's extremely easy to check for yourself.
Have you checked or do you just have a feeling about this?

And let's be honest, DJI doesn't have the best record with such things.

Really?
Can you point to anything specific?

I recommend you guys do the same to see if you see a difference in how fast and quick they are.

Fast and quick?
That's like saying something is big and large.
I think you're perhaps being overly non-specific in your use of terms.

 

[canadian drone videos]

Your description sounds like a classic yaw error incident.
Interference won't ever cause your drone to fly off like that.
You can still have the flight data looked at to confirm the cause and possibly learn from the incident and how to prevent similar from happening again.

Log showed joystick input at 21% and stayed at exactly 21% until it crashed. Meanwhile I had to duck out of the way as the drone buzzed by my head then slammed into the house. You ever been buzzed by an Inspire 2, not fun. I argued with DJI for 2 months over that drone, convinced the RC malfunctioned. They never did look at the flight log, I sent then mine and they had the drone so they had theirs too. Said they couldn’t open mine, and couldn’t get theirs from the drone. They initially called it pilot error, fascinating. I had to get a lawyer to help me with that incident.

 

[sar104]

I think you're perhaps being overly pedantic with fast specifically used to refer to top speed vs acceleration. But I still think it is quicker and faster than the M2P.

If you use the term "much faster" and then say you didn't mean it actually goes faster, I don't think it's pedantic of me at all to point that out.

In terms of tilt angle, I imagine just like with FPV, the prop size/angle matters and so does the motor. Are props/motor rpm equal between them?

You imagine wrong - all those things are irrelevant because in level flight the total motor thrust, T, has to be partitioned, via tilt, so that the vertical component is always equal to the weight of the aircraft, Mg. So at tilt θ,

Tcosθ = Mg (1)​

​

and

​

Tsinθ = Ma (2)​

​

Dividing equation (2) by equation (1) gives

a = gtanθ​

​

In other words the linear horizontal acceleration is only a function of tilt.

I also don't 100% trust the advertised numbers. And let's be honest, DJI doesn't have the best record with such things. But I will say, it's a good starting point.

Then post some logs showing sustained flight faster than the DJI specifications.

 

[Meta4]

I had to get a lawyer to help me with that incident.

If the flight data showed what you describe, you probably could have achieved a happy outcome without the need for a lawyer.
Several times, members have been able get help here to have DJI to reconsider when their data analysis has been incorrect.