MM1 How much would a steady15mph sustained wind hold back the MM1

FlyBackOU812 · Feb 15, 2021

This was a matter of a very heated post in a group recently. I'd really like to get a lot of responses on this and if you would give a brief explanation on why your answer was your answer if you're confident in your answer. If you're not sure, say that, but at least give an educated guess or your opinion on how you came up with your answer. The question is... The MM1 will fly 30mph unrestricted, in zero wind,, in sport mode. So if it was facing a 10mph sustained and constant head wind if it was possible. How much would that slow the minies speed down to ? Would it be
A)35mph?
B)30mph
C)40mph
D) I don't know?
E) none at all
Thanks... I may have to run some test and find out. That is if I get enough responses to make it worth while

Edit... in the post I wrote 15mph, TYPO, that was only for content and I don't see a way to edit the original post in the forum, so let's go with the 10mph as far as answering the question. Thanks
Also... please don't delete or edit your answer after I've commented on replies. I need it to stay as was or people won't get why it its so controversial. Again...Thank you

Meta4 · Feb 15, 2021

FlyBackOU812 said:
This was a matter of a very heated post in a group recently. I'd really like to get a lot of responses on this and if you would give a brief explanation on why your answer was your answer if you're confident in your answer. If you're not sure, say that, but at least give an educated guess or your opinion on how you came up with your answer. The question is... The MM1 will fly 30mph unrestricted, in zero wind,, in sport mode. So if it was facing a 10mph sustained and constant head wind if it was possible. How much would that slow the minies speed down to ? Would it be
A)35mph?
B)30mph
C)40mph
D) I don't know?
E) none at all
Thanks... I may have to run some test and find out. That is if I get enough responses to make it worth while

Is there any reason that you didn't have any options that would show any slowing of the Mini?
And you say a 15 mph wind in the thread title, but 10 mph in the question.

There's no mystery about the arithmetic though.
If the discussion was heated, Facebook doesn't have many physicists.
The problem is very simple.
The top speed in Sport Mode shown in the specs is 29 mph.
If fighting a 10 mph headwind, the Mini's speed over the ground would be 19 mph.

It's the same as being able to row your dinghy at 5 mph in still water.
But if you try rowing upstream against a 10 mph current, you would still go backwards downstream at 5mph.

Yogi053 · Feb 15, 2021

Answers A and C!!!!! Just how do you expect a drone to fly faster against a headwind??????
My answer, FWIW, is I Don't Know!

surfbird · Feb 15, 2021

Hehe thats a tricky question

I can't say for the mini, but most of DJI-drones are limited in ground-speed AND attitude which come first.
So the you can't answer question without any more info about the drone.

I think most mavic's are limited to 19m/s groundspeed. So they actually refuse to go any faster in tail wind.

slup · Feb 15, 2021

FlyBackOU812 said:
...The question is... The MM1 will fly 30mph unrestricted, in zero wind,, in sport mode. So if it was facing a 10mph sustained and constant head wind if it was possible. How much would that slow the minies speed down to ? Would it be
A)35mph?
B)30mph
C)40mph
D) I don't know?
E) none at all

Yeah your post is really confusing ... think you have missed out from some vital thing's in that other thread you're referring too.

In general it's really simple ... if the AC is up on max speed & starts to be pushed by something coming from the opposite direction (a headwind) you will see a decrease in AC speed.

So with the values mentioned in you post ... it will be 30mph - 10mph = AC speed decreases to 20mph.

It's nothing strange here so far ...

But then of course the SW in the AC can change the behavior slightly in other modes than the Sport mode (which usually allows the AC to max out the tilt angle & by that also the speed).

For instance my own MA1, the MA2 & the Mini 2 prioritize the maximum speed in slower modes than Sport. They allow the AC to utilize tilt angles into Sport mode territory in order to maintain the AC ground speed in head winds.

MA2:

Mini 2:

For my own MA1 DJI doesn't mention this ... but have noticed this behavior during my flights in headwinds.

During the orange circled portion of this flight my MA1 was flying straight into a headwind that momentarily slowed it down ... then the AC started to utilize the Sport mode tilt angle (even though it was in P-mode) & it again could maintain those 8m/s it was specified for in P-mode.

This is from the DAT log so wind calculation is available ... the tilt angle for P-mode should be 25 degrees & for Sport 35 degrees. In the circled area in the chart the MA1 is actually tilting like it's in Sport ...

scro · Feb 15, 2021

Be aware that ground speed and airspeed are only the same if there is NO wind. As soon as there is a little bit of wind the 2 are different. The speed readout given in the app is ground speed.

The MM1 has a maximum ground and air speed of 29mph in sport mode. If you're flying into a 10mph headwind the max air speed will be 29mph, but the ground speed will be slower by 10mph (ie 19mph)

If flying with a 10mph tailwind then the limit of 29mph on ground speed will stop you from achieving a ground speed of anything more than 29mph. The air speed will be less than the ground speed (ie 19mph) as the aircraft is partially "drifting" with the wind.

In short, regardless of conditions, the maximum speed the MM1 will do is 29mph

Zbip57 · Feb 15, 2021

scro said:
If flying with a 10mph tailwind then the limit of 29mph on ground speed will stop you from achieving a ground speed of anything more than 29mph. The air speed will be less than the ground speed (ie 19mph) as the aircraft is partially "drifting" with the wind.

If flying with a 30mph tailwind, will the Mini then be backpedalling at -1mph to limit its groundspeed to 29mph? ?

CareyL · Feb 15, 2021

FlyBackOU812 said:
This was a matter of a very heated post in a group recently. I'd really like to get a lot of responses on this and if you would give a brief explanation on why your answer was your answer if you're confident in your answer. If you're not sure, say that, but at least give an educated guess or your opinion on how you came up with your answer. The question is... The MM1 will fly 30mph unrestricted, in zero wind,, in sport mode. So if it was facing a 10mph sustained and constant head wind if it was possible. How much would that slow the minies speed down to ? Would it be
A)35mph?
B)30mph
C)40mph
D) I don't know?
E) none at all
Thanks... I may have to run some test and find out. That is if I get enough responses to make it worth while

You have identified why I sold my Mini 1. Your question is put in a biased way. You start by saying the mini's max speed but not that it has to be in Sports mode to achieve it. Usually we take off in Normal positioning mode and you will find that 15 mph on the ground usually equals something very different 30' up. This is why the discussion groups were filled with "my Mini flew away" topics during its first year. Better have your emergency procedure well rehearsed!

slup · Feb 15, 2021

Zbip57 said:
If flying with a 30mph tailwind, will the Mini then be backpedalling at -1mph to limit its groundspeed to 29mph? ?

Yes ... in that case. If flying with a tailwind the max ground speed for the mode is prioritized ... The AC pitch down will decrease enough to keep the specified speed.

If you look at the chart in my post #5 & study the red graph ... where the graph goes lower (tilt angle decreases) it's when my MA1 have circled back in the sat.pic. & started to have a nearly full tailwind ... but still the speed (blue graph) remains around those 8m/s which is max for P-mode... but he tilt/pitch is only 3 degrees, so not yet "breaking", but nearly. Compare that with the green graph just there in the end in the chart ... the wind speed is around 8m/s.

Rich QR · Feb 15, 2021

Zbip57 said:
If flying with a 30mph tailwind, will the Mini then be backpedalling at -1mph to limit its groundspeed to 29mph? ?

How about with a 65 mph tailwind? I'd love to see it backpedal at 36mph!

Meta4 · Feb 15, 2021

Rich QR said:
How about with a 65 mph tailwind? I'd love to see it backpedal at 36mph!

The folks that wanted to talk about tailwinds haven't noticed that in a (more than gentle) tailwind the drone will go a little over the limited speed.
If the tailwind was 65 mph, that would be more than a little, but the drone can only resist up to it's maximum speed ability.
In the hypothetical scenario, it's likely to be blown away at 65-29 = 36 mph.

m80116 · Feb 15, 2021

Air speed is air speed no matter what the ground underneath does. If the AC capability is 30 mph if it received a head-on wind for 10 mph it will go 20 mph compared to ground distance and effectively 30 mph into the wind.

This without netting the real battery capabilities which may me affected as it drains, restricting power and dropping voltage.

Meta4 · Feb 15, 2021

m80116 said:
This without netting the real battery capabilities which may be affected as it drains, restricting power and dropping voltage.

The battery's voltage decreases during flight but the drone's max speed is not reduced as long as the cell voltages are above critical low voltage level.

FlyBackOU812 · Feb 15, 2021

Meta4 said:
Is there any reason that you didn't have any options that would show any slowing of the Mini?
And you say a 15 mph wind in the thread title, but 10 mph in the question.

There's no mystery about the arithmetic though.
If the discussion was heated, Facebook doesn't have many physicists.
The problem is very simple.
The top speed in Sport Mode shown in the specs is 29 mph.
If fighting a 10 mph headwind, the Mini's speed over the ground would be 19 mph.

It's the same as being able to row your dinghy at 5 mph in still water.
But if you try rowing upstream against a 10 mph current, you would still go backwards downstream at 5mph.

I guess i typed a typo with the wind speed, ill fix, thanks.
The problem with being able to look at your speed to know the effect the wind is having is that we have no way of knowing the exact wind speed at any given moment that is pushing against the drone at that moment.
As far as your answer, NOT TRUE. Its not as simple as you suggest it is, hence the heated post.. your answer... Not true. Your arithmetic adds up just fine, its the equation that you're using that is wrong. With your equation that would mean the wind would react the same to every object. If that were true aerodynamics wouldn't be thing... ?

FlyBackOU812 · Feb 15, 2021

Yogi053 said:
Answers A and C!!!!! Just how do you expect a drone to fly faster against a headwind??????
My answer, FWIW, is I Don't Know!

I never said anything about it being able to fly faster. Im not sure where that response is coming from

FlyBackOU812 · Feb 15, 2021

surfbird said:
Hehe thats a tricky question

I can't say for the mini, but most of DJI-drones are limited in ground-speed AND attitude which come first.
So the you can't answer question without any more info about the drone.

I think most mavic's are limited to 19m/s groundspeed. So they actually refuse to go any faster in tail wind.

There seems to be a confusion with my question, which I'm trying to work out but I've yet been able to figure out where in my question its getting confused. Maybe you could help me out with that answer. Thanks

FlyBackOU812 · Feb 15, 2021

slup said:
Yeah your post is really confusing ... think you have missed out from some vital thing's in that other thread you're referring too.

In general it's really simple ... if the AC is up on max speed & starts to be pushed by something coming from the opposite direction (a headwind) you will see a decrease in AC speed.

So with the values mentioned in you post ... it will be 30mph - 10mph = AC speed decreases to 20mph.

It's nothing strange here so far ...

But then of course the SW in the AC can change the behavior slightly in other modes than the Sport mode (which usually allows the AC to max out the tilt angle & by that also the speed).

For instance my own MA1, the MA2 & the Mini 2 prioritize the maximum speed in slower modes than Sport. They allow the AC to utilize tilt angles into Sport mode territory in order to maintain the AC ground speed in head winds.

MA2:
View attachment 123870
Mini 2:
View attachment 123871

For my own MA1 DJI doesn't mention this ... but have noticed this behavior during my flights in headwinds.

During the orange circled portion of this flight my MA1 was flying straight into a headwind that momentarily slowed it down ... then the AC started to utilize the Sport mode tilt angle (even though it was in P-mode) & it again could maintain those 8m/s it was specified for in P-mode.

View attachment 123872

This is from the DAT log so wind calculation is available ... the tilt angle for P-mode should be 25 degrees & for Sport 35 degrees. In the circled area in the chart the MA1 is actually tilting like it's in Sport ...

View attachment 123873

I love your reply giving the DAT file screenshot to go along with your answer. BUTTT... LOL... There are parts of this equation you aren't figuring into it. With your figures, that would mean the wind pushes on all obstacles alike(All aircraft) what you aren't accounting for is the aerodynamics and surface area that will GREATLY effect each aircraft differently ?

FlyBackOU812 · Feb 15, 2021

scro said:
Be aware that ground speed and airspeed are only the same if there is NO wind. As soon as there is a little bit of wind the 2 are different. The speed readout given in the app is ground speed.

The MM1 has a maximum ground and air speed of 29mph in sport mode. If you're flying into a 10mph headwind the max air speed will be 29mph, but the ground speed will be slower by 10mph (ie 19mph)

If flying with a 10mph tailwind then the limit of 29mph on ground speed will stop you from achieving a ground speed of anything more than 29mph. The air speed will be less than the ground speed (ie 19mph) as the aircraft is partially "drifting" with the wind.

In short, regardless of conditions, the maximum speed the MM1 will do is 29mph

You seem to missing the point and the over all reason of the discussion. That may well be from the way I worded it, for that I appoligize sincerely, im trying to work that issue out as I speak. Thank you. But it seems noone has yet determined into the equation that aerodynamics also plays a vital role in being able to correctly determine the answer. With your answer, that would mean every object reacts the exact same way to the wind which is not a fact.
I guess I should have said ground speed or the app speed. But im not sure if that is the confusing part or if there's also another part as well. Again... I'm working on that. Your response was helpful in the area of ground speed tho. Thank you for your reply

FlyBackOU812 · Feb 15, 2021

Zbip57 said:
If flying with a 30mph tailwind, will the Mini then be backpedalling at -1mph to limit its groundspeed to 29mph? ?

I'm not sure why you answered the question with a question of your own and without an answer to the underlying question at hand. Your question is obviously not possible and has nothing to do with the purpose of this post. Altho its a very good question for some that don't understand anything about how all this works lol..This can only confuse others further. Not trying to be an ( Mod Removed Language)here, I promise. I actually value your opinion andis why I'm disappointed in your reply. I guess I expected more from you on this subject because its something that ive never seen discussed and important for pilots to understand if they are determining whether or not they should fly on account of an app based wind speed and what it means. Thanks for your reply but I'd much rather know your answer to the question and how you came up with it. Means a lot to me and to the pilots that read this that have some influence on other pilots as you do. Thanks zbipp