Scary experience tonight, Lesson learned?

[Paradigm]

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.

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.


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

IME, it's accelerates faster and has a faster top speed, therefore is faster and quicker. I don't think people universally mean top speed when they say fast, wrt drones.

If I cap the top speed of my FPV drone to 5 mph under the M2P/M3, I think most people will still (erroneously if being pedantic) claim that the FPV drone is faster because it accelerates at a significantly higher rate, although the top speed will still be slower. But, I suppose let's agree to disagree because we're not about to run an experiment to find out.

Of course what I was getting at is the motor and propeller difference between the M2P and M3 is such that the M3 has more thrust. Perhaps I wasn't clear when I said "Are props/motor rpm equal between them?" So, more thrust, more aerodynamic, and less weight... would lead me to believe it is faster.

I will concede that there are other variables such as stick rate and video transmission FPS that may alter the experience between them. I would love to see a poll and both drones tested in a scientific manner to settle this once and for all.

 

[sar104]

IME, it's accelerates faster and has a faster top speed, therefore is faster and quicker. I don't think people universally mean top speed when they say fast, wrt drones.

If I cap the top speed of my FPV drone to 5 mph under the M2P/M3, I think most people will still (erroneously if being pedantic) claim that the FPV drone is faster because it accelerates at a significantly higher rate, although the top speed will still be slower. But, I suppose let's agree to disagree because we're not about to run an experiment to find out.

Of course what I was getting at is the motor and propeller difference between the M2P and M3 is such that the M3 has more thrust. Perhaps I wasn't clear when I said "Are props/motor rpm equal between them?" So, more thrust, more aerodynamic, and less weight... would lead me to believe it is faster.

I will concede that there are other variables such as stick rate and video transmission FPS that may alter the experience between them. I would love to see a poll and both drones tested in a scientific manner to settle this once and for all.

Since you have chosen to ignore the specifications, declined to post a log file to support your "feelings", repeatedly attempted to change the definition of faster to suit your mobile goalposts, and apparently didn't understand anything that I wrote in post #59, I'm not going to waste any more time debating it.

 

[slup]

... I was getting at is the motor and propeller difference between the M2P and M3 is such that the M3 has more thrust.
... So, more thrust, more aerodynamic, and less weight... would lead me to believe it is faster.

Well ... let's break down the facts a bit & see where that leads us.

Here the specs for a M2P & a M3 Standard ... have made "heavier, faster & bigger" in bold & equal in red.

Mavic 2:

Weight (Pro) = 907g
Max tilt = 35 degrees
Max speed = 20m/s
Prop diameter = 8,7"
Prop pitch = 4,3"
Prop weight = 7,9g

Mavic 3:

Weight (Standard) = 895g
Max tilt = 35 degrees
Max speed = 19m/s
Prop diameter = 9,4"
Prop pitch = 5,3"
Prop weight = 8,5g

And here a pic showing how thrust, gravity & drag effect a drone ...



From the specs we know that the M2 both have a higher top speed, is 12g heavier, have a smaller prop diameter with a shallower pitch & the same max tilt of 35 degrees... compared to the M3.

This means that the light blue vertical thrust part needs to be larger for the M2 in order to counteract the red weight if the craft should be able to maintain the height.

When the M2 tilts forward to it's maximum 35 degree tilt angle, the light blue vertical part of the thrust will be smaller as some of the total thrust will be shifted to a horizontal part, green arrow. But as the light blue vertical thrust part gets smaller with an increase of tilt it can no longer counteract the red weight which is constant ... the craft will lose height. To prevent a height loss the motors will increase it's rpm in order to generate more thrust up to the level where the light blue thrust part again counteract the red weight.

The speed the craft can perform this maneuver without loosing height depends on how quickly the additional thrust can be generated ... or how quickly the motor can increase it's rpm. The time it takes for the motor to increase the rpm & the prop to generate more thrust regulates how quickly the flight controller allows the craft to change the tilt ... (if height should be maintained).

It's common knowledge that a smaller, lighter prop with a shallower pitch reacts quicker ... is more agile, but on the other hand isn't as efficient due to a smaller disc area (need to constantly have a higher rpm) & have less grip (more slip) in turns compared to a larger prop with a steeper pitch.

So the conclusion would be that ... the M2 generates more thrust in max forward flight with a constant height as it's heavier ... it also should accelerate faster (as it should be quicker to change the rpm) due to it's smaller prop with a shallower pitch ... & it looks also to have less drag as it's top speed is higher than the M3.

The only thing that can change this, as stated out from the specs, to a opposite feeling ... is how the M3 reacts on the sticks compared to the M2, nothing else. And it's by now commonly known that the M3 is way twitchier & much more sensitive to the sticks if compared to the M2's default setup.

 

[Paradigm]

Well ... let's break down the facts a bit & see where that leads us.

Here the specs for a M2P & a M3 Standard ... have made "heavier, faster & bigger" in bold & equal in red.

Mavic 2:

Weight (Pro) = 907g
Max tilt = 35 degrees
Max speed = 20m/s
Prop diameter = 8,7"
Prop pitch = 4,3"
Prop weight = 7,9g

Mavic 3:

Weight (Standard) = 895g
Max tilt = 35 degrees
Max speed = 19m/s
Prop diameter = 9,4"
Prop pitch = 5,3"
Prop weight = 8,5g

And here a pic showing how thrust, gravity & drag effect a drone ...

View attachment 140476

From the specs we know that the M2 both have a higher top speed, is 12g heavier, have a smaller prop diameter with a shallower pitch & the same max tilt of 35 degrees... compared to the M3.

This means that the light blue vertical thrust part needs to be larger for the M2 in order to counteract the red weight if the craft should be able to maintain the height.

When the M2 tilts forward to it's maximum 35 degree tilt angle, the light blue vertical part of the thrust will be smaller as some of the total thrust will be shifted to a horizontal part, green arrow. But as the light blue vertical thrust part gets smaller with an increase of tilt it can no longer counteract the red weight which is constant ... the craft will lose height. To prevent a height loss the motors will increase it's rpm in order to generate more thrust up to the level where the light blue thrust part again counteract the red weight.

The speed the craft can perform this maneuver without loosing height depends on how quickly the additional thrust can be generated ... or how quickly the motor can increase it's rpm. The time it takes for the motor to increase the rpm & the prop to generate more thrust regulates how quickly the flight controller allows the craft to change the tilt ... (if height should be maintained).

It's common knowledge that a smaller, lighter prop with a shallower pitch reacts quicker ... is more agile, but on the other hand isn't as efficient due to a smaller disc area (need to constantly have a higher rpm) & have less grip (more slip) in turns compared to a larger prop with a steeper pitch.

So the conclusion would be that ... the M2 generates more thrust in max forward flight with a constant height as it's heavier ... it also should accelerate faster (as it should be quicker to change the rpm) due to it's smaller prop with a shallower pitch ... & it looks also to have less drag as it's top speed is higher than the M3.

The only thing that can change this, as stated out from the specs, to a opposite feeling ... is how the M3 reacts on the sticks compared to the M2, nothing else. And it's by now commonly known that the M3 is way twitchier & much more sensitive to the sticks if compared to the M2's default setup.

Thak you for the write up.

The only issue that comes up is it appears you're implying that the heavier weight is beneficial by bolding it. Also, I'm not certain I believe DJI and their specs.

 

[Meta4]

Thak you for the write up.

The only issue that comes up is it appears you're implying that the heavier weight is beneficial by bolding it.

The weight difference of 1.3% is not enouigh to make any significant difference.

Also, I'm not certain I believe DJI and their specs.

So you said, but it means nothing without some more details.
Which specs don't you believe?
What evidence do you have to substantiate this?
Some recorded flight data would be helpful.

 

[Paradigm]

The weight difference of 1.3% is not enouigh to make any significant difference.

So you said, but it means nothing without some more details.
Which specs don't you believe?
What evidence do you have to substantiate this?
Some recorded flight data would be helpful.

Every gram counts, I believe and they add up. In FPV, granted different bit similar, you notice flight characteristic differences between your battery packs...

Do you believe DJI's battery specs? How about their transmission specs? Perhaps their other spotty behavior such as the color tint issue being within spec. I'm sure there's more, but I think I make a fair point.

I agree. We need flight logs for some definitive.

 

[Meta4]

Do you believe DJI's battery specs? How about their transmission specs?

I do.

their other spotty behavior such as the color tint issue being within spec.

What spec?

I'm sure there's more, but I think I make a fair point.

You haven't made a point at all ... just mentioned that you have a feeling.

 

[slup]

I'm not certain I believe ...

Nah ... that's not the way to engage in a tech discussion, you may believe what you want but you can't convince others with that kind of abstract argument.

...it appears you're implying that the heavier weight is beneficial

By no means ... it's just the laws of physics. The weight of something that's been kept airborne at a constant altitude needs a counteracting force equally large ... so heavier needs a larger force, and that force is thrust. So your feeling that the M3 have a larger thrust is wrong.

Every gram counts...In FPV, granted different bit similar, you notice flight characteristic differences between your battery packs...

Agreed, they counts ... but not for the max speed or acceleration on a constant altitude horizontal flight (especially not 12g).

Have several quads ranging from below 250g all up weight, up to above 800g with vastly different powerful motors. Given the same tilt angle (35 degrees which is my camera up-tilt on all my quads) they all cruise at around 70km/h or 19,5m/s in a level flight & accelerate equal. What differs is how much throttle I have to apply to counter the quad weight to keep a constant altitude. So it's not a coincident that all drones with a max tilt angle of 35 degrees ends up with a top speed of around 19-20m/s.

 

[Paradigm]

@Meta4 People are having color tint issues with some of their M3's. At first DJI agreed it was an issue and started replacing the drones. People have returned 2, 3, etc. Eventually DJI said that's it, the color tint is within spec. It is most certainly not and their claim is laughable. That's just one issue, there are more with other drones... As for the other things I mentioned, people have tested battery life and range and often times they're not within spec, either for the better or worse. It's not uncommon for companies to fudge the specs, from Apple to Toyota. I'm not sure why you believe DJI above actual users, given a large enough sample size, controlled variables etc. I'm not saying DJI's specs are to be completely dismissed, in case that's what you're getting from this. I think they're a great starting point, if not mostly accurate.

 

[Paradigm]

By no means ... it's just the laws of physics. The weight of something that's been kept airborne at a constant altitude needs a counteracting force equally large ... so heavier needs a larger force, and that force is thrust. So your feeling that the M3 have a larger thrust is wrong.


Agreed, they counts ... but not for the max speed or acceleration on a constant altitude horizontal flight (especially not 12g).

We need to run some tests. If you have the M2P and the M3, fly them back to back after equalizing how your sticks react.

 

[Meta4]

@Meta4 People are having color tint issues with some of their M3's. At first DJI agreed it was an issue and started replacing the drones. People have returned 2, 3, etc. Eventually DJI said that's it, the color tint is within spec. It is most certainly not and their claim is laughable.

There is no mention of colour tint or anything similar in the specifications for any DJI drone.
You are talking about something completely different.

As for the other things I mentioned, people have tested battery life and range and often times they're not within spec, either for the better or worse.

The data shown in DJI specs for signal range and battery life have been generated from laboratory testing under ideal conditions.
These things can vary from the results that you might observe in your local environment and the way you fly for a whole range of reasons.
You may not understand that, but it doesn't mean their published specs are not completely valid.

It's not uncommon for companies to fudge the specs, from Apple to Toyota. I'm not sure why you believe DJI above actual users, given a large enough sample size, controlled variables etc. I'm not saying DJI's specs are to be completely dismissed, in case that's what you're getting from this. I think they're a great starting point, if not mostly accurate.

So if Apple and Toyota do it (according to you), then DJI also does?
I believe DJI's specs because over years of flying DJI drones and reading forums, I've found them to be reliable.

So far you haven't come up with anything more specific than you have a feeling that DJI specs aren't accurate.
See if you can point to a concrete example where you've found their published specs to be incorrect, rather than something you (or someone you've heard of) couldn't get the same flight time or distance.

 

[Point Zero]

As an impartial viewer I must say that some of these discussions can easily become a bit fraught.

This in my mind is when two rather different forces collide.

On the one side you have the OP's with their personal experiences and points of view, looking for help of some kind and on the other you have the analytical types that take on only real world verifiable data and with this data they can offer the help the OP's are looking for.

When they are not presented with the data they need which is mostly flight logs then the discussions tend to become polarised.

I kind of wish that people would post their flight logs more often but in the same breath I understand why they choose not to sometimes.

 

[Don Testme]

Well this evening I decided to take off my drone from my balcony. I have done this several times before but this time the drone took off and behaved very erratically and uncontrollably. As it launched a few feet out, the drone swerved in severe direction and did not respond to my piloting commands appropriately. She swerved into a tree and got stuck about 15 feet up. I had to toss a broom at her and she fell out of the tree. I was quick to break the fall with my hands and it was painful but worth it. No damage. I was able to test the drone and flew around for 30 minutes everything working swell. I am sure this is from the poor choice of selecting bypass mode. I am thinking from now on to always either select brake, or off but never bypass. Bypass apparently has the possibility of causing the aircraft to behave very unpredictably. Also it was a lower light situation so that could be part of it. Not dark but not bright either.

I am wondering if bypass is just a poor choice in general and brake is the better option for drone safety.

I found the best thing to do when a drone does this, is CLIMB AS FAST AS POSSIBLE TO WHATEVER ALTITUDE THE DRONE ALLOWS. This , obviously, will prevent the drone from hitting anything. Then it can fly all over the place until it gets a good GPS lock or stops for whatever reason, then you can fly it home. If it's flying out of control because of a malfunction, well then, I guess you may lose it. I usually see most drones only do this temporarily and then they stabilize. In my experience, just climbing as far as I can and waiting is usually the best route to take.

 

[Paradigm]

There is no mention of colour tint or anything similar in the specifications for any DJI drone.
You are talking about something completely different.

The data shown in DJI specs for signal range and battery life have been generated from laboratory testing under ideal conditions.
These things can vary from the results that you might observe in your local environment and the way you fly for a whole range of reasons.
You may not understand that, but it doesn't mean their published specs are not completely valid.


So if Apple and Toyota do it (according to you), then DJI also does?
I believe DJI's specs because over years of flying DJI drones and reading forums, I've found them to be reliable.

So far you haven't come up with anything more specific than you have a feeling that DJI specs aren't accurate.
See if you can point to a concrete example where you've found their published specs to be incorrect, rather than something you (or someone you've heard of) couldn't get the same flight time or distance.

RE: Color tint. DJI saying it's within spec while discussing it with people who are requesting a refund because of it. While not published in the spec sheet, they are still specifications provided by DJI and they moved the goal posts to deny more returns based on the haze. It's an example of their specifications changing. At first, they are out of spec, then they are not. Which is it?

I understand how battery life and signal range is tested. I also think it's dishonest and misleading; with DJI hiding behind an asterisk. A range in common situations would be ideal, but of course that wouldn't look as good, would it? Funny how a YT reviewer, and forum posters, can give me a more accurate and realistic range/battery specifications than the company can.

My point about Toyota/Apple is that it's common enough for corporations to do such a thing. Of course, because they do that does not mean DJI must do it as well, which would be a logical fallacy.

I don't necessarily trust self-tested and self-published results from a company, who frankly, doesn't have a spotless record. I do think they're a good starting point... Which leads us to needing logs. But I still implore you to fly both back-to-back and report back to us.

 

[Meta4]

While not published in the spec sheet, they are still specifications provided by DJI and they moved the goal posts to deny more returns based on the haze. It's an example of their specifications changing. At first, they are out of spec, then they are not. Which is it?

Where is this "specification" that you say is provided by DJI?
I very much doubt it exists anywhere.

I understand how battery life and signal range is tested. I also think it's dishonest and misleading; with DJI hiding behind an asterisk. A range in common situations would be ideal, but of course that wouldn't look as good, would it? Funny how a YT reviewer, and forum posters, can give me a more accurate and realistic range/battery specifications than the company can. It's that you don't understand what specs are.

Your issue isn't that DJI have provided specs that aren't accurate.
It's that you don't understand what specs are and how they work

But I still implore you to fly both back-to-back and report back to us.

Fly what back to back and report on what?

 

[JoshC]

This happened to me before with my Mavic 3 when lunching from my balcony as well. The APAS 5 act very strange and the drone behave very nervously and uncontrollable when is inside the balcony having so many walls and fence close to it. What I do to resolve the problem is as soon as I take off, switch to sport mode and disable the APAS sensors. When I leave from the balcony to the open area then I switch back to normal. Then before going back to the balcony I land in sport mode as well.

The Mavic 3 APAS is very aggressive and needs to be fine-tuned. The same thing happens when you try to hand-land the drone.

I do the same with my Mavic 2 Pro, Mavic Air 2, and DJI Mini 2 without problems.

You activate sport mode when taking off and landing on an apartment balcony? Good luck

 

[kakao]

... and still no log file to resolve the whole issue!?

Huh ...!