Mini 2 DJI Mini 2 Forced Landing after searching for Petroglyphs

[Paleomanjim]

I got a little carried away searching and videoing Petroglyphs in the local desert at Little Red Rock yesterday. The battery got down to 0%, the wind came up and the Mini 2 was forced down. This area is under construction for new homes and all roads in are marked no trespassing so I parked over 2 miles away and hiked part way in. Sounds a bit strange I guess but I actually enjoy the experience of hunting for lost drones!

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[Deleted member 103366]

Did you switch to the map view during the early part of the return return?
At 4000+ft (when the map first appears) you were almost certainly beyond VLOS ( that is a factual consideration, I am not seeling to initiate a VLOS discussion) so flying either via the camera-view or the map.
I have switched to the map when returning from distance and it is a great aid in ensuring that the drone is coming home even when watching the drone. I would suggest it is much better than trying to aim the drone via the camera view unless you really know the area and or have a really clear landmark to judge things by.
I have to say it put up a valiant struggle.

 

[Paleomanjim]

Did you switch to the map view during the early part of the return return?
At 4000+ft (when the map first appears) you were almost certainly beyond VLOS ( that is a factual consideration, I am not seeling to initiate a VLOS discussion) so flying either via the camera-view or the map.
I have switched to the map when returning from distance and it is a great aid in ensuring that the drone is coming home even when watching the drone. I would suggest it is much better than trying to aim the drone via the camera view unless you really know the area and or have a really clear landmark to judge things by.
I have to say it put up a valiant struggle.

Thanks. The map view is probably a good idea, I will have to give it a try. The wind came up quickly and blew me to the side and I mostly focused on the distance until I realized I was not getting much closer and checked the compass view to see I was way off track. The constant alarms below 20% battery are really annoying and distracting, 1 alarm at 20% and another at 10% would be better imo. I have hiked that area many times and am familiar with it. Kinda hate to see them putting houses out there since its really a special place.

 

[Deleted member 103366]

Thanks. The map view is probably a good idea, I will have to give it a try. The wind came up quickly and blew me to the side and I mostly focused on the distance until I realized I was not getting much closer and checked the compass view to see I was way off track. The constant alarms below 20% battery are really annoying and distracting, 1 alarm at 20% and another at 10% would be better imo. I have hiked that area many times and am familiar with it. Kinda hate to see them putting houses out there since its really a special place.

Being deaf has its advantages, no aural alarms lol

 

[MAvic_South_Oz]

Being deaf has its advantages, no aural alarms lol

Yep.
"Did you say Hole point recorded, please check it on the mat ??" ha ha

 

[MAvic_South_Oz]

Never been in that situation, but my plan is . . .

When at that stage 2:55 in your video (attempting forced landing, or even at a little less critical stage) go with it, gimbal down, find a spot that looks good and head to it.
Somewhere obviously flat and clear to land, but also a notable land feature you can walk to and orientate to look for the drone.
A dry creek bed there would probably be ideal, easy to follow a creek bed along, even if battery fails.

Obviously have enough battery left to last the walk to the drone using the map (or then find my drone).

The beeping and flashing might help some, the visual for me might as I can't hear those high tones.
A good feature on the later drones.

 

[MAvic_South_Oz]

We have petroglyphs here in Australia too, the indigenous Aboriginal people have left their marks.
They look amazingly similar to those in your video.

These taken by regular phone camera in the remote Western Australian Pilbara region . . .

 

[macfawlty]

I got a little carried away searching and videoing Petroglyphs in the local desert at Little Red Rock yesterday. The battery got down to 0%, the wind came up and the Mini 2 was forced down. This area is under construction for new homes and all roads in are marked no trespassing so I parked over 2 miles away and hiked part way in. Sounds a bit strange I guess but I actually enjoy the experience of hunting for lost drones!

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You gotta trust the low battery warnings. Try hunting for a drone in a difficult to access heavily wooded area on the side of a mountain, chasing daylight, hours from home with no cell service or satellite imagery and see how much you like it when you’re buying a new one! If you’re running low on battery, switch to sport mode to RTH faster, be sure to capture video on your return that best shows your flight back and learn to identify tree leaves (assuming there are trees) or land forms you’ll see in your proxy files as you descend or crash. Don’t rely on the beeping and flashing function of the drone as the drone may shut down if the motors are overloaded or it runs out of battery. Get a ArcLight XL and/or Marco Polo as a backup. I speak from multiple experiences. Recovery is key. Consider all the factors I mentioned when taking risks, but not low battery… that’s never worth the risk.

 

[Deleted member 103366]

switch to sport mode to RTH faster

Uuum is not the wholely automated RTH speed fixed at a maximum ground speed and or a maximum angle of tilt, possibly at the max speed in P mode and or.....(I am not certain what should go here in relation to the angle of tilt)?
Yes it may be possible to increase teh RTH speed if the drone is in sports mode by pushing the elevator forward but the need to command the speed increase need to be highlighted. A change of flight mode will, I think, cancel existing RTH.
Also there is the question as to whether flat out in Sports mode would burn more battery per m than flat out in P mode. It's a complicated question.

 

[MAvic_South_Oz]

A change of flight mode will, I think, cancel existing RTH.
Also there is the question as to whether flat out in Sports mode would burn more battery per m than flat out in P mode. It's a complicated question.

Yes, switching to Sports mode does cancel RTH, you'd have to drop low and fly home manually.
Yes, it's been hashed out a bit on the forum, would burn more juice.

But, if you aren't making headway (enough) in P mode or RTH, then getting closer might be better in some cases, or at least get somewhere flat and recognisable to put it down yourself for retrieval.

Turn off obstacle avoidance is something you could do to get more speed, or just have it turned off from the start of a flight.
Certainly OA isn't needed in many drone flights, only low and / or slow stuff through such places as it's obviously handy to have on.

 

[Phantomrain.org]

Excellent video , its actually very hard to do what you did from a such a distance , so my hat is off to you, Well done and well navigated.

It was very cool seeing those relics.

Phantomrain.org
Gear to fly in the Rain.

 

[macfawlty]

Yes, switching to Sports mode does cancel RTH, you'd have to drop low and fly home manually.
Yes, it's been hashed out a bit on the forum, would burn more juice.

But, if you aren't making headway (enough) in P mode or RTH, then getting closer might be better in some cases, or at least get somewhere flat and recognisable to put it down yourself for retrieval.

Turn off obstacle avoidance is something you could do to get more speed, or just have it turned off from the start of a flight.
Certainly OA isn't needed in many drone flights, only low and / or slow stuff through such places as it's obviously handy to have on.

Good to know. I'm not the foremost authority on optimal methods for return on low battery. My RTH is often set at a higher altitude than a preferred return (given wind velocity at higher altitudes), so canceling the RTH and switching to Sport mode might be preferable? I'll have to search for a thread on the topic, cuz it would be good to have clarification. One of the issues I have with my M2P is the awfully slow rate of descent, which is not helpful if you're returning against the wind and with ridge loft and thermals.

 

[Deleted member 103366]

It is better to set an appropriate RTH height at the start of each flight such that the drone will clear any obstacles by a safe margin e.g. 30ft, rather than set a carte blanche high RTH cover all.
You can change the RTH height whilst the drone is in flight BUT you can not change it whilst the drone is actually executing an RTH.
An unnecessarily high RTH height wastes power and possibly exposes the drone to stronger winds, as you have noted.
BUT remember the height is relative to the take off point, so if you flew the drone uphill and descended behind trees or rocks etc. the RTH BUYheight must be high enough above the take off point to clear those obstacles. Descending behind obstacles was by way of an example and not meant to be taken literally as it may cause a loss of connection etc..
REMEMBER also that it is likely that you can cause the drone to descend whilst it is RTH'ing you do not need to leave it at excessive height. CHECK THIS.

 

[Paleomanjim]

Thanks everyone. I was using a Mini 1 Li-ion battery for this flight with over 120 charge cycles on it, so no doubt it has lost a bit of range over time. The winds seemed to be around 10-15 mph at the time, not too bad but no doubt higher at altitude. The stock Lipo battery's perform a little better and give around 15% better range. Speed on both batteries will tend to drop as battery gets below 15% but it is usually very minimal until around 5%. Lipo batteries on Mini 2 can fly at least 2700' at 0% battery. Watch the below video (not mine). Pretty incredible! Li-ion batteries apparently do not (at least in my case). I was thinking about this video when I was trying to get back thinking I might make it. Regarding choosing between S Mode and N mode it is true that N mode will give around 15% better range, I have tested it, but that assumes 0 wind conditions. If wind is slowing the drone down below 10 mph it seems to make sense to switch to S mode. As for RTH I have my setting maxed out to avoid hitting mountains. When I loose connection I let the drone RTH until the signal is restored (usually 100' of elevation does it) and then continue flying manually.

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[Micky52]

Just a tought!
In this scenario, would it be possible (or does it exist) to have a mini solar panel on top of drone to very lightly recharge battery and come back next day or so to complete return home ?

 

[Deleted member 103366]

Nice thinking but, even if one exists, I doubt there's the space to fit it on a Mini 2 and what happens if the drone flips or lands in a shaded area e.g. a tree.

 

[Micky52]

Nice thinking but, even if one exists, I doubt there's the space to fit it on a Mini 2 and what happens if the drone flips or lands in a shaded area e.g. a tree.

Well, I was thinking more like a ultra thin plastic stick on kind of solar cell.
Of course with very low charging but in the case of a controlled emergency landing, chances are drone is upright.
Anyway was just a thought, with no real additional weight to the unit, could be a viable solution (I think)
Thanks for your opinion Phil..

 

[Deleted member 103366]

Wow, those are news so me, guess I should stick my nose above the parapet more often, THANKS.
But, now knowing that such things might be available, I see one other possible problem. The drone will not normally charge its battery when the drone is switched on. If the drone drains the battery to power off then the drone can not be remotely switched on.
In order for your idea to work it might be necessary to connect the solar cells' output directly to the battery (that worries me) or do some other jiggery pokery. It would be nice if it could be made to work.

 

[Micky52]

Wow, those are news so me, guess I should stick my nose above the parapet more often, THANKS.
But, now knowing that such things might be available, I see one other possible problem. The drone will not normally charge its battery when the drone is switched on. If the drone drains the battery to power off then the drone can not be remotely switched on.
In order for your idea to work it might be necessary to connect the solar cells' output directly to the battery (that worries me) or do some other jiggery pokery. It would be nice if it could be made to work.

Ya, I see your point.
If battery drain switches drone off, Theoratically with battery charged up again (enough to power on) then back home possibly possible.
Again this is all theoretical (like a bit of a brain storming LOL on an idea). Like you said, solar cell would be stuck to the top of Battery with permanent hook-up to battery.
If enough people talk about it, we could maybe get to a solution. (almost everything is possible) if we work at it.
Thanks

 

[MAvic_South_Oz]

If enough people talk about it, we could maybe get to a solution. (almost everything is possible) if we work at it.

When I first read your reply, I knew it was unfeasible . . . at the moment.
Like you say, everything on the planet started with an idea.

A long time ago someone thought "What if we put 4 little motors on this X shape frame, and make a flying machine that uses motor speed to propel in any direction ?"
"Might be fun." (And useful.)