Hello,

Considering all the respect for Mavic Mini product and the physical and mechanichal limitations of such small device, I've wondered why in the exemplified fatal circunstance of loosing connection betweeb drone and RC, upon self RTH activation from the device wich works on P mode, if the device keeps drifting away from the takeoff point, why not a device critical self activation of the S mode on RTH? In such example, there are few (if none) chances of restoring connection to RC because the drone will keep drifting away on RTH - P mode and the pilot cannot engange S mode upont connection failure (whatever might be the reason). I'm I missing a point here and sorry if so but if this is true, asside the fact that none of us should fly at circunstances that are not compliant with the product especifications, this type of fly away may happen at normal circunstances at several places where wind gusts at 30mt may be different when mesured at ground level and some may not have time or experience to react to the wind warnings. Thank you.

Do we know if that doesn't actually already occur? I have seen a lot of log analysis of fly aways, and I don't recall the analysis experts saying that the AC wasn't performing at its max. Maybe in those incidents it was already in S mode I guess, but seems weird that I haven't seen this in those discussions. Here or on the Mavic Pilots site.

Thank you Deucalion. Fair enough, this is mainly a doubt of me and yes, I’ve seen already the same question at drone pilots forum and some validated the P mode at the RTH. What made me question if there is any sort of “auto S mode engagement” in case of wind drifting on RTH.

Cordiero Posted at 4-29 07:19
Thank you Deucalion. Fair enough, this is mainly a doubt of me and yes, I’ve seen already the same question at drone pilots forum and some validated the P mode at the RTH. What made me question if there is any sort of “auto S mode engagement” in case of wind drifting on RTH.

When I went up high I was in Cinema mode and got strong wind warnings, and the warning about RTH etc. I instinctively switched to sport mode, but I don't know if that is really necessary for RTH. This would be a good thread for a moderator to jump in and answer.

In the video that I posted yesterday, regarding the procedure for an emergency ditching at a remote location, you can see what happens with the return speed when you hit RTH.

If RTH is activated while you still have a good control signal, the RTH speed stays at whatever settting you're using unless you choose to change it.

If the control signal is lost (I turned off my controller), the RTH speed automatically changes to P-mode.

Zbip57 Posted at 4-29 08:29
In the video that I posted yesterday, regarding the procedure for an emergency ditching at a remote location, you can see what happens with the return speed when you hit RTH.

If RTH is activated while you still have a good control signal, the RTH speed stays at whatever settting you're using unless you choose to change it.

Oh cool, good to know. Now you need to try that on a really windy day.

”If the control signal is lost (I turned off my controller), the RTH speed automatically changes to P-mode.”

Thank you. So it behaves as I suspected thus, It’s fair my concern and maybe makes sense my point: The device upon be unable of performing auto-RTH (couldn’t face winds) should engage automatically S mode.

Because if we try to evaluate optional procedures for recover control on a RC connection lost on a device that starts to be pushed away on wind, there is nothing that can be done unless engage S mode to try fight the winds. If there is no way to engage it manually and auto-RTH kicks off, the device should be able to evaluate by itself that P mode is useless on that case and engage automatically S mode as the only and final chance to return to home point or get close enough to the pilot in order to re-establishes connection.

Deucalion Posted at 4-29 08:32
Oh cool, good to know. Now you need to try that on a really windy day.

P mode is cool?  I though you were thinking we needed S-mode?

The Saint Posted at 4-29 09:15
P mode is cool?  I though you were thinking we needed S-mode?

If it is windy, yeah we need S mode. But if not, I am fine with P mode. I was just saying cool that it switched up from Cinema mode to P mode.

Your craft is rated to fly in certain winds, these parameters are not a guesstimate they are an actual and it’s up to you to respect them, most dji drones travel back in Rth mode at similar speeds, with loss of signal if your craft is now no longer under the control of the operator so from what I know because there is no one controlling the drone having it fly in sport mode would only add to the problems that may be caused by flying without any operator control, so your parameters are set before you fly and it’s your responsibility to comply.
If you are still in control and want to use Rth you can and you then have full control of speed and altitude while in Rth mode.

At startup the default mode is always P-mode, as you can see in the video above.

At 1:00 I switched to C-mode because I prefer to fly slowly.  At 2:20 I manually initiated RTH while in C-mode, and it remained in that mode while returning.  While in RTH mode, and you still have a control signal, you can change anything you like, steer it left/right up/down or change to P-mode or S-mode, etc.

At 4:30, still in C-mode as it's descending in Auto-Land, I turn off the controller to cause a loss of control signal.  As described in the user manual, eleven seconds after loss of control signal the Mini will engage its Failsafe routine.  After I switch the controller back on and it regains a control signal at 5:35 you can see it has now switched back to P-mode.

I'll leave it to the more adventurous among you to test whether it would automatically switch to S-mode when trying to return home in high winds, but I suspect it won't.

Would it be a good idea if DJI fixed it so that RTH was always done in Sport-mode?  I don't think so.  You already have the option to manually switch to S-mode when trying to fight a strong wind.  If that's not enough, then RTH at S-mode isn't going to be any better.  It's probably going to be worse if the Mini first climbs to a higher alititude where the winds are probably stronger.


If you're already struggling to get back home using S-mode against a strong wind, you better start thinking about doing an emergency ditching in a location of your choice while you still can, rather than waiting until you lose control signal.  Watch my video above.  If you end up relying on RTH against a strong wind (with no control signal), bad things will almost certainly happen...

I should add, if you are already struggling to bring the Mini back against a strong wind while using Sport-mode, then the siituation will most definitely become much worse after you lose control signal and the Mini automatically switches to the slower P-mode in RTH.  

Zbip57 Posted at 4-29 10:06
I should add, if you are already struggling to bring the Mini back against a strong wind while using Sport-mode, then the siituation will most definitely become much worse after you lose control signal and the Mini automatically switches to the slower P-mode in RTH.

Yeah, in that case it is good to know how to switch RTH to land in place and find a nice spot to put it down.

I perfectly understand your comment and request, but I also do believe one must check the weather, there's a couple of apps and more websites that offer wind forecasts for the altitude you're interested to fly into. And always obey at the FIRST Strong Wind Warning notice... don't wait that it reiterates. One is enough to stop and wait... two for me is enough to head back and LAND for good, at least for the time and zone.

Zbip57 Posted at 4-29 09:59
At startup the default mode is always P-mode, as you can see in the video above.

At 1:00 I switched to C-mode because I prefer to fly slowly.  At 2:20 I manually initiated RTH while in C-mode, and it remained in that mode while returning.  While in RTH mode, and you still have a control signal, you can change anything you like, steer it left/right up/down or change to P-mode or S-mode, etc.

You cannot change orientation during Rth IE “left or right”  only up down speed fwd and Yaw

hallmark007 Posted at 4-29 11:09
You cannot change orientation during Rth IE “left or right”  only up down speed fwd and Yaw

My apologies.  You are correct, and I was wrong,  I went outside just now and tried it.

While in RTH enroute to the Home Position, one cannot change its flight path.  Full stick input left/right is ignored.  It cannot be made to deviate from its straight path home, unless you cancel RTH to regain manual control.

You do however have full control left/right, forward/back, yaw, even up/down, during RTH mode after the Mini has reached a point directly above the Home Position and has started its descent.

Zbip57 Posted at 4-29 14:09
My apologies.  You are correct, and I was wrong,  I went outside just now and tried it.

While in RTH enroute to the Home Position, one cannot change its flight path.  Full stick input left/right is ignored.  It cannot be made to deviate from its straight path home, unless you cancel RTH to regain manual control.

“You do however have full control left/right, forward/back, yaw, even up/down, during RTH mode after the Mini has reached a point directly above the Home Position and has started its descent.”


Again not sure if above is a mistake but you mention left/right you cannot move craft left or right, edit my fault on descents you can move left right

To the OP: This subject has been argued many times...usually very emotionally to say the least. I am in favor of letting Mini do whatever is in it's capability to "survive" when on it's own and that includes using the faster mode to cope. Others want to stay pure and require the operator to take more care of the situation in advance. If that means losing the drone, then so be it.

Today was an interesting case in point. At noon, the wind was calm, under 5 knots and I was tempted to try a flight. But being a sailor for many decades in my location, I knew the wind frequently came up after noon, turning to the opposite direction. It did with a vengeance about 1 PM. This was local knowledge and not on any forecast. Someone with less experience in the area would have had a problem.

Deucalion Posted at 4-29 07:15
Do we know if that doesn't actually already occur? I have seen a lot of log analysis of fly aways, and I don't recall the analysis experts saying that the AC wasn't performing at its max. Maybe in those incidents it was already in S mode I guess, but seems weird that I haven't seen this in those discussions. Here or on the Mavic Pilots site.

Do we know if that doesn't actually already occur? I have seen a lot of log analysis of fly aways, and I don't recall the analysis experts saying that the AC wasn't performing at its max. Maybe in those incidents it was already in S mode I guess, but seems weird that I haven't seen this in those discussions.
Some of us know lots about DJI drones including the Mini.
It doesn't matter what mode the Mini is flying in, when it loses signal and initiates RTH or if you initiate RTH manually, the drone will go into RTH mode and the max speed of RTH mode is 8 metres/sec (18 mph).
On top of that, the Mini is plagued by a problem that can cause it to fail to maintain proper speed and slow down even more.

The Mini is a slow, underpowered drone and anyone puting it up in strong winds will learn an unpleasant lesson.

Dirty Bird Posted at 4-30 04:56
If you search there are numerous threads on this subject.  It has been debated & discussed ad nauseum.  

Summary - The Mini RTH speed is 17.9 mph (8 meters per second).   That's what you've got to work with.  If you fly in strong winds & suspect you may lose contact, fly into the wind, or perpendicular to the wind,  so the bird has a chance to make it back.

Thanks. That is good info.

Zbip57 Posted at 4-29 08:29
In the video that I posted yesterday, regarding the procedure for an emergency ditching at a remote location, you can see what happens with the return speed when you hit RTH.

If RTH is activated while you still have a good control signal, the RTH speed stays at whatever settting you're using unless you choose to change it.

I’ll reply to you on this thread as I don’t want to further hijack other thread.

If you lose signal in C mode your craft will revert to P mode you don’t need to turn anything off and on with S mode exactly the same, when flying in sport or C mode and and you initiate RTH craft will also revert to both speed and pitch of Pgps mode, there is absolutely no such thing as Rth in any other mode except Pgps. And it’s careless and wrong to say anything else.

You can clearly see in screenshot that when flying in C mode that speed is equal to P mode and pitch will also be same as pitch mode to enable speed for P mode.

Someone could confirm it, : With a tailwind, can the MM, in RTH mode, fly at more than 8meters / sec?   ....Or maybe the FC is trying to maintain 8meters / sec  ?

JGFly Posted at 5-2 09:30
Someone could confirm it, : With a tailwind, can the MM, in RTH mode, fly at more than 8meters / sec?   ....Or maybe the FC is trying to maintain 8meters / sec  ?

If you had lost signal it would be hard to know, but wind has an effect on drones going into and downwind, although I believe there is a governor applied downwind don’t know exactly what it is for mini.

But if you have initiated RTH you can use your controls to control speed altitude and yaw, you can effect everything except orientation. Many people use Rth and use the yaw to film the aircraft keeps a straight line while you use yaw to pan and film as mini returns home.

Using right stick full forward you can gain Sam speed as you get in sport mode while craft remains in p mode.

hallmark007 Posted at 5-2 11:26
If you had lost signal it would be hard to know, but wind has an effect on drones going into and downwind, although I believe there is a governor applied downwind don’t know exactly what it is for mini.

But if you have initiated RTH you can use your controls to control speed altitude and yaw, you can effect everything except orientation. Many people use Rth and use the yaw to film the aircraft keeps a straight line while you use yaw to pan and film as mini returns home.

Understood (already knew that, saw in one of your recent Post)

So,  if there's a tail wind, let say MM is flying in RTH (initiated by pilot or after contact lost),   with a tail wind of 25 mph, will it fly at  speed P mode + 25 mph ???

Thanks! and sorry If I mistunderstood your Reply.

JGFly Posted at 5-2 13:11
Understood (already knew that, saw in one of your recent Post)

So,  if there's a tail wind, let say MM is flying in RTH (initiated by pilot or after contact lost),   with a tail wind of 25 mph, will it fly at  speed P mode + 25 mph ???

No unfortunately I believe the speed is governed so it’s more likely to increase speed approx 5mph plus top speed P mode, I have tried sport mode at 20/25 kph and all I could manage above top speed was 7kph .

hallmark007 Posted at 5-2 13:29
No unfortunately I believe the speed is governed so it’s more likely to increase speed approx 5mph plus top speed P mode, I have tried sport mode at 20/25 kph and all I could manage above top speed was 7kph .

Ok thanks for the  information.

Deucalion Posted at 4-29 07:15
Do we know if that doesn't actually already occur? I have seen a lot of log analysis of fly aways, and I don't recall the analysis experts saying that the AC wasn't performing at its max. Maybe in those incidents it was already in S mode I guess, but seems weird that I haven't seen this in those discussions. Here or on the Mavic Pilots site.

I'm thinking that is already occurring.

Vlas Posted at 5-2 14:01
I'm thinking that is already occurring.

That's because you haven't read the posts above that explain that it doesn't.

Labroides Posted at 5-2 14:53
That's because you haven't read the posts above that explain that it doesn't.

A shame.

No I haven't read everything but here's my experience. My RTH was self activated while in C mode it would move to RTH alt, then over to Over Home close to P mode speed and descended in the C mode I was flying/filming in that mode when I realize it's  moving slowly.  If wind gust come up the draw I fly over I beat feet to my field so I can get to lower alts.

hallmark007 Posted at 5-2 06:03
I’ll reply to you on this thread as I don’t want to further hijack other thread.

If you lose signal in C mode your craft will revert to P mode you don’t need to turn anything off and on with S mode exactly the same, when flying in sport or C mode and and you initiate RTH craft will also revert to both speed and pitch of Pgps mode, there is absolutely no such thing as Rth in any other mode except Pgps. And it’s careless and wrong to say anything else.

I will admit I did not know that.  Learn something new every day.  I ran a few experiments today to confirm and you are absolutely correct.

Despite whatever is currently displayed in the app, C-mode, P-Mode, or S-Mode, the Mini will always travel at P-Mode airspeed (8m/s) whenever in Return-to-Home.

JGFly Posted at 5-2 09:30
Someone could confirm it, : With a tailwind, can the MM, in RTH mode, fly at more than 8meters / sec?   ....Or maybe the FC is trying to maintain 8meters / sec  ?

I'm itching to experiment with that too, but it would be safer to do this in a large open field than here surrounded by lakes and forest.

Don't hesitate to correct me (again), but the speed displayed on the app screen would most likely be showing groundspeed, right?  It can accurately calculate that by measuring the rate of change in GPS location.

If it's RTH airspeed is always 8m/s and it's struggling to fight upwind against an 8m/s headwind, it would effectively be making zero groundspeed.

If the windspeed is greater than 8m/s, let's say 10m/s, the drone would not be making any progress against the headwind, but will be pushed backward at 2m/s groundspeed.

If the drone is flying at 8m/s RTH airspeed with a 10m/s tailwind, it should then be travelling at 18m/s groundspeed.

Zbip57 Posted at 5-3 11:58
I'm itching to experiment with that too, but it would be safer to do this in a large open field than here surrounded by lakes and forest.

Don't hesitate to correct me (again), but the speed displayed on the app screen would most likely be showing groundspeed, right?  It can accurately calculate that by measuring the rate of change in GPS location.

Hallmark007 already answered above    Post 33

Cheers !

JGFly Posted at 5-3 12:21
Hallmark007 already answered above    Post 33

Cheers !

I saw his answer, but I really don't understand what he's saying.

Hallmarlk007 wrote, "I believe the speed is governed [...] I have tried sport mode at 20/25 kph and all I could manage above top speed was 7kph ."

What does that mean exactly?

Top speed in S-mode is 13m/s (46.8kph).  It sounds like he's saying flying downwind at the 46.8kph max airspeed, with a 20/25 kph tailwind, he was limited to a speed increase of only 7 kph because of a speed governor?  Am I understanding that correctly?

Zbip57 Posted at 5-3 14:15
I saw his answer, but I really don't understand what he's saying.

Hallmarlk007 wrote, "I believe the speed is governed [...] I have tried sport mode at 20/25 kph and all I could manage above top speed was 7kph ."

you wrote''...    Am I understanding that correctly? ''

Yes.

Governed mean If I'm not mistaken  IMU,  FC (Flight controller) etc  All working together for properly piloting the drone

To be verified by Others in this thead so wait for them answering correctly.

I must quit now

Cheers !
  

Zbip57 Posted at 5-3 14:15
I saw his answer, but I really don't understand what he's saying.

Hallmarlk007 wrote, "I believe the speed is governed [...] I have tried sport mode at 20/25 kph and all I could manage above top speed was 7kph ."

What I basically said was going downwind speed was governed, ie if your flying downwind in Rth the max speed for Rth May increase but very slightly, I have often tested speed manually downwind to see how fast a craft could go with wind behind and said that flying downwind no matter how strong the most I could achieve was approx 7kph above top speed. Ie see photo below of Mavic pro top speed 40 mph top recorder speed 74kph so 7kph more than top speed downwind.

hallmark007 Posted at 5-3 14:56
What I basically said was going downwind speed was governed, ie if your flying downwind in Rth the max speed for Rth May increase but very slightly, I have often tested speed manually downwind to see how fast a craft could go with wind behind and said that flying downwind no matter how strong the most I could achieve was approx 7kph above top speed. Ie see photo below of Mavic pro top speed 40 mph top recorder speed 74kph so 7kph more than top speed downwind.

[view_image]

Okay, got it now.  You're suggesting there is an absolute speed limit governed at ~7km/h more than the drone's max airspeed rating.  

I still think you're mixng apples and oranges here. I could see how, in completely calm air, if you give it full forward stick input the drone will accelerate hard to its topspeed, and possibly overshoot by a bit (7km/h?) before steadying at its rated topspeed, which for the Mini in S-mode is 13m/s (47km/h).  

But how or why would it ever be considered necessary to choke back topspeed (groundspeed?) with a governor when flying downwind?

47+7=54 km/h governed groundspeed.

If the Mini were merely drifting at zero airspeed downwind in a 54km/h tailwind, you wouldn't be able to apply any additional forward stick without exceeding the governed speed limit.
In anything faster than a 54km/h tailwind, the drone would even need to be backpedalling in order to stay under the speed limit.
In an extreme 54+47=101 km/h wind, the Mini would have to be backpedalling for all it's worth against the wind, using its full 47km/h S-mode airspeed capability just to remain under the 54km/h governed groundspeed limit.
At anything over 101 km/h windspeed, not even the governor could keep the drone from exceeding 54km/h groundspeed.
This should be easy enough to test out, but it requires a windy day and enough space to experiment in.

Zbip57 Posted at 5-3 16:00
Okay, got it now.  You're suggesting there is an absolute speed limit governed at ~7km/h more than the drone's max airspeed rating.  

I still think you're mixng apples and oranges here. I could see how, in completely calm air, if you give it full forward stick input the drone will accelerate hard to its topspeed, and possibly overshoot by a bit (7km/h?) before steadying at its rated topspeed, which for the Mini in S-mode is 13m/s (47km/h).  

I’m not sure why speed is governed but it seems parameters are set, so dji must have ratings for each drone they won’t let them go above, we know because of hacked programs speeds can be greatly increased , I think mini would have great difficulty in getting started in 54kph so unless you get it up and shoot off knowing you’re not getting it back I’m sure wind would greatly increase how fast it would go, but downwind 54kph will probably drive mini into the ground and it won’t be because of bad props .