MM2 Noob - User manual clarifications..

[pjw188]

My apology in advance as this is a long post.

I have read the User's guide and all other relevant publications cover to cover as well as viewed 30+ videos. I have a few questions I am hoping can be clarified here. I am not sure how much credibility to give the user manual. Some of the information appears contradictory.

Page 38 mentions:
"Mobile cellular data is required when using DJI Fly. Contact your wireless carrier for data charges."
Can I only fly where I have cell service or wifi? This would seem pretty restrictive to me.

Page 14/15/16 mentions:
"There are three types of RTH: Smart RTH, Low Battery RTH, and Failsafe RTH"
I am coming from old-school Phantom Vision 2+ frame of mind. On this system, you could set your own custom battery thresholds for RTH. Yes I know the newer systems are different, but I just need some clarification:

I get "Smart RTH". No questions.

Low Battery RTH
"When the Intelligent Flight Battery level is too low and there is not enough power to return home, land the aircraft as soon as possible. Otherwise, the aircraft will fall when it runs out of power, resulting in the aircraft being damaged and other potential hazards."

This tells me I should do this manually. Wouldn't "Low Battery RTH" do this automatically?
What am I missing?
Then the next paragraph says:
"Low Battery RTH is triggered when the Intelligent Flight Battery is depleted to the point that the safe return of the aircraft may be affected".
I am confused. Do "I" initiate it, or does the IBMS/quad?

"DJI Mini 2 will intelligently determine whether the current battery level is sufficient to return home based on the current location."
Does it take into account the amount of power necessary to climb to the configured RTH altitude as well as the horizontal distance, hovering and landing when making this decision? Am I overthinking/second guessing this system?

Failsafe RTH
"If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds. When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH."

Does it take into account including the power necessary for the 50 meter back tracking?

What does "straight line RTH" mean? Does it mean following a direct radian from the 50 meter back track point at the RTH altitude back to the recorded Home Point?

"The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH."
If I read this correctly, the quad is already in a straight line RTH from the loss of controller for 11 seconds (see above). How can it re-enter a state it's already in?

"When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude."
I am totally lost on this statement.

"RTH Procedure (Straight Line)"
"1. The Home Point is recorded." Understood.
"2. RTH is triggered. Understood."

"3. If the aircraft is less than 20 m from the Home Point when RTH begins, it will hover in place and not return to home (firmware version v1.1.0.0 is required. Otherwise, the aircraft will land immediately). If the aircraft is further than 20 m from the Home Point when RTH begins, it will return home at a horizontal speed of 10.5 m/s."
No clue.

4. "After reaching the Home Point, the aircraft lands and the motors stop." Understood.

"During RTH, the speed, altitude, and orientation of the aircraft can be controlled using the remote controller if the remote controller signal is normal. However, the remote controller cannot be used to pan left or right."
What is "pan left or right"? Camera?

Thank you in advance for your patience with this noob.

 

[old man mavic]

@pjw188 firstly pan left or right means in mode 2 the right stick will not move the drone in a sideways motion, you can still yaw the drone lose or gain height and push the right stick up to increase the speed ,when my MPP goes into RTH then it just goes up to the preset height i have set turns around, and comes back regardless of which way it was pointing at the time ,the newer drones have a system where they will retrace there last movement back along a similar line ,to try and establish a signal connection back to the controller
after this time if no reconnection is possible then they just come home as normal back to the take off point
if the distance is less than 20m then it does not do the fly backwards part of the RTH sequence,it just returns home at its present height
i am not the owner of the Mini2 just have the original MM which exhibits the same RTH characteristics as my MPP in that it doesnt fly backwards ,before coming home it is probably because it does not have the occusync transmission system of the Mini2 , i can understand your confusion as the translation into English of the manual does throw up some anomalies
you do not need cellular to fly the drone you just need a WIFI connection to be able to do updates ,in fact most people using a phone go into aircraft mode which stops incoming calls from interrupting the flight
straight line RTH means that the drone will take the shortest route back to the home point from wherever it is at the time (or as the crow flies ) this is one of the reasons for setting a suitable RTH height to make sure it clears any tall obstacles in its path on the way home and also dont forget the MM and Mini2 dont have any obstacle avoidance sensors like the larger drones do

 

[pjw188]

Old Man Mavic, Thank you very much for the detailed reply. Yes, the manual is quite confusing sometimes. NOW I understand why the RTH sequence has the "retrace" feature. To try and regain a weak signal that it KNOWS it had at one point. That makes sense.

 

[Repaid1]

My apology in advance as this is a long post.

I have read the User's guide and all other relevant publications cover to cover as well as viewed 30+ videos. I have a few questions I am hoping can be clarified here. I am not sure how much credibility to give the user manual. Some of the information appears contradictory.

Page 38 mentions:
"Mobile cellular data is required when using DJI Fly. Contact your wireless carrier for data charges."
Can I only fly where I have cell service or wifi? This would seem pretty restrictive to me.
Disregard this, Not sure what the heck they were going for it needs no connection although Maps will load onsite. You need a DJI account set up and your App needs the initial log in to Account, beyond that no connection is "required".
Page 14/15/16 mentions:
"There are three types of RTH: Smart RTH, Low Battery RTH, and Failsafe RTH"
I am coming from old-school Phantom Vision 2+ frame of mind. On this system, you could set your own custom battery thresholds for RTH. Yes I know the newer systems are different, but I just need some clarification:

I get "Smart RTH". No questions.

Low Battery RTH
"When the Intelligent Flight Battery level is too low and there is not enough power to return home, land the aircraft as soon as possible. Otherwise, the aircraft will fall when it runs out of power, resulting in the aircraft being damaged and other potential hazards."

This tells me I should do this manually. Wouldn't "Low Battery RTH" do this automatically?
What am I missing?
Then the next paragraph says:
"Low Battery RTH is triggered when the Intelligent Flight Battery is depleted to the point that the safe return of the aircraft may be affected".
I am confused. Do "I" initiate it, or does the IBMS/quad?
Not sure what they are calling this function now. It used to be user set for the first alert before the critical battery alarm and autoland, someone will have to clarify what it means on the Mini's. IT may be that Low Battery and Intelligent RTH are the same?
"DJI Mini 2 will intelligently determine whether the current battery level is sufficient to return home based on the current location."
Does it take into account the amount of power necessary to climb to the configured RTH altitude as well as the horizontal distance, hovering and landing when making this decision? Am I overthinking/second guessing this system? It just gives a good guess based on power used going out, if you follow the rule when you went out as to fly into headwind, it will get you home safe and sound and land with power to spare in most "normal" situations.
Failsafe RTH
"If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote controller signal is lost for more than 11 seconds. When the firmware is updated to v1.1.0.0 and above, the aircraft will fly backwards for 50 m on its original flight route and ascend to the preset RTH altitude to enter Straight Line RTH."

Does it take into account including the power necessary for the 50 meter back tracking?
(Yes)
What does "straight line RTH" mean? Does it mean following a direct radian from the 50 meter back track point at the RTH altitude back to the recorded Home Point?
(It means it will rise to set RTH altitude, Yaw to take off point and from there fly a straight line home.)

"The aircraft enters Straight Line RTH if the remote controller signal is restored during Failsafe RTH."
If I read this correctly, the quad is already in a straight line RTH from the loss of controller for 11 seconds (see above). How can it re-enter a state it's already in?
No it is actually in back track mode, if during this phase it gets signal back it then will yaw and rise to correct RTH height and bee line to takeoff or homepoint as set.
"When the aircraft flies backwards along the original flight path and the distance from the Home Point is less than 20 m, the aircraft stops flying backward on the original flight route and enters Straight Line RTH at the current altitude."
I am totally lost on this statement.
"RTH Procedure (Straight Line)"
"1. The Home Point is recorded." Understood.
"2. RTH is triggered. Understood."

"3. If the aircraft is less than 20 m from the Home Point when RTH begins, it will hover in place and not return to home (firmware version v1.1.0.0 is required. Otherwise, the aircraft will land immediately). If the aircraft is further than 20 m from the Home Point when RTH begins, it will return home at a horizontal speed of 10.5 m/s."
No clue.
If you are within 20 M (60 foot) from launch RTH spot it won't rise and orient to fly home (It figures you are close enough to walk to it and establish signal or whatever). IF you are outside of that range it will orient to homepoint rise to set altitude and bee line home and land at launch point

4. "After reaching the Home Point, the aircraft lands and the motors stop." Understood.

"During RTH, the speed, altitude, and orientation of the aircraft can be controlled using the remote controller if the remote controller signal is normal. However, the remote controller cannot be used to pan left or right."
What is "pan left or right"? Camera?
As answered, Aircraft Yaw
Thank you in advance for your patience with this noob.

See answers in red above. More clarification just ask

 

[pjw188]

Repaid1, Thank you for the detail. This clears up a lot of ambiguity within the manual.

 

[Repaid1]

Repaid1, Thank you for the detail. This clears up a lot of ambiguity within the manual.

No problem mate...been flying these things for 6+ years and my DJI Chinglish is pretty good now.

 

[Deleted member 103366]

Once you think you understand what will happen in an RTH scenario go out, to a wide open space, and initiate it and see if observed behaviour matches your expectations.
I do not own a Mini 2 but I have been caught out by the RTH behaviour of a Mini ( I did not know how to stop a climb to a ludicrous high and accidentally set RTH height and, as I was at the edge of signal range, I did not want to interupt the RTH), a Phantom 3 ( distance vs behaviour) and a Mavic 2 (other alterable parameters affecting the RTH behaviour).
I think the more complicated the range of possible behaviours the greater the need to experience them in a safe practise situation BEFORE you encounter them in real life.
Do not set a routine RTH height, rather set it for each flying situation and be aware that you can probably reset the RTH height whilst in flight, i.e. if you come across an object that you would like to see the far side of and that is tops out near or above your RTH height then measure its height with the drone and add maybe 10m to that and reset your RTH height to that sum.
Quite a few early Mavic Minis were lost due to people flying behind such objects then, when the control signal was lost, the drone RTH'd and flew into the object.

 

[pjw188]

Once you think you understand what will happen in an RTH scenario go out, to a wide open space, and initiate it and see if observed behaviour matches your expectations.
I do not own a Mini 2 but I have been caught out by the RTH behaviour of a Mini ( I did not know how to stop a climb to a ludicrous high and accidentally set RTH height and, as I was at the edge of signal range, I did not want to interupt the RTH), a Phantom 3 ( distance vs behaviour) and a Mavic 2 (other alterable parameters affecting the RTH behaviour).
I think the more complicated the range of possible behaviours the greater the need to experience them in a safe practise situation BEFORE you encounter them in real life.
Do not set a routine RTH height, rather set it for each flying situation and be aware that you can probably reset the RTH height whilst in flight, i.e. if you come across an object that you would like to see the far side of and that is tops out near or above your RTH height then measure its height with the drone and add maybe 10m to that and reset your RTH height to that sum.
Quite a few early Mavic Minis were lost due to people flying behind such objects then, when the control signal was lost, the drone RTH'd and flew into the object.

Philius, this is great advice. In addition to doing this, I think I need to get to a wide open area, and practice following the "red line on the map" back to the home point. Thank you.