1st ever - Fly Away!

[Kilrah]

OK yep people it was my fault ( once again )

Might want to change the title then - a "fly away" is used to describe a loss of control and inability to do anything due to faulty aircraft behavior rather than a pilot error. There it did exactly what it was supposed to.

Good thing you managed to save it, and find the now very obvious reason

 

[BudWalker]

Hmm, so I've been thinking about it and am a little confused on how the Mavic determines it's airspeed. Initially I was thinking like a normal aircraft, but duh, it doesn't have a pitot/static system so it must be coming from the GPS... but then I thought about it and it still displays the speed when in ATTI mode (correct?), so the airspeed must be coming from another source, maybe IMU?

So how is the Mavics airspeed calculated?

The speed displayed in the tablet app and the log files is ground speed. It's not air speed.

 

[Logger]

That's an interesting observation. Logical and absolutely correct as it relates to cars. However, Pushing full forward really isn't flooring it with the Mavic. Sport mode full forward is but I'm willing to bet full forward with obstacle avoidance off is pretty close to max efficiency.

So in my car no I would not floor it... with my Phantom and Mavic yep full forward absent sport mode. It has always worked for me..and I'm frequently testing the range limits of all my birds.

YEP totally agree. And if anyone doesn't believe this, allow your Mavic to fly around until it triggers a low battery RTH button and observe what speed DJI have programmed it to come home at. Mine comes home at around ~30mph. Which is nearly twice the stated max endurance speed of 15.5mph.
For this reason I have planned any long Litchi routes I do at this sort of speed too and I am satisfied that it works producing near to best range.

 

[silmslice]

So if you were running out of gas in your car and not sure if you could make it to the next gas station would you just floor it?

Motors and engines have a rpm range that delivers the most efficient use of fuel be it gas or battery powered. Maintaining that range gives you the best chance of making it to your destination. Add in the fact that as you increase airspeed drag in greatly increased which relates directly to fuel/energy consumption.

My guess is that the Mavic's most efficient cruse speed is somewhere around the limit that is set (22 mph?) when you hit RTH.

I'm just going to make an assumption one efficiency, on the mavic specs page, dji states that max battery life is 27minutes and I would assume this is flying in optimum conditions, they also state in brackets that this is with no wind and flying at 25kph (15.5mph).
So my assumption that 25kph would be the most efficient cruise speed.

*edit: Realised that this efficiency is for the longest battery life, not necessarily longest distance covered, travelling faster may reduce flight time but you would also travel further, so what I wrote above may be irrelevant*

I have no idea how accurate this is and haven't done any testing because I am still waiting for my magic to arrive (I CANT WAIT!!)

Also relating to the OP, I have read/saw somewhere that in the settings you can alter what the magic does when it loses signal, default is set to return to home (either take off location or gps/controller location), OR you can set it to descend where it is, OR you can set it to hover.
Perhaps setting it to hover when you lose signal would be best when flying over water and changing location. (Although it seems as though you have sorted the weak gps problem)


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[StGr]

I read this post with interest. I am new at this so just want to confirm that the error
Was that your smart phone GPS was not on and turning that feature on does indeed resolve the problem. Thx for clarifying.

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[m0j0]

YEP totally agree. And if anyone doesn't believe this, allow your Mavic to fly around until it triggers a low battery RTH button and observe what speed DJI have programmed it to come home at. Mine comes home at around ~30mph. Which is nearly twice the stated max endurance speed of 15.5mph..

As I said before. With many long range flights where I needed to efficiently get my birds back I always have flown them back at full stick forward. I always got them back.

 

[f3honda4me]

So if you were running out of gas in your car and not sure if you could make it to the next gas station would you just floor it?

Motors and engines have a rpm range that delivers the most efficient use of fuel be it gas or battery powered. Maintaining that range gives you the best chance of making it to your destination. Add in the fact that as you increase airspeed drag in greatly increased which relates directly to fuel/energy consumption.

My guess is that the Mavic's most efficient cruse speed is somewhere around the limit that is set (22 mph?) when you hit RTH.

The 22mph is because that is the maximum speed mavic can fly at with obstacle avoidance working.

 

[Logger]

As I said before. With many long range flights where I needed to efficiently get my birds back I always have flown them back at full stick forward. I always got them back.

Yep and that is exactly why DJI have set RTH to fly home near flat out. Seems this is where best SGR is.

 

[m0j0]

The 22mph is because that is the maximum speed mavic can fly at with obstacle avoidance working.

The OA should be turned off if you are "downrange" and short of battery. It will remove the 22mph speed cap and eliminate the possibility that OA will initiate a false obstruction alert. When flying toward the sun the OA system sometimes registers an obstruction. A false obstruction alert will cause the Mavic to follow the parameters you set in the application..hover, climb to avoid... etc. valuable time lost that has resulted in forced landings and lost Mavics.


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[f3honda4me]

The OA should be turned off if you are "downrange" and short of battery. It will remove the 22mph speed cap and eliminate the possibility that OA will initiate a false obstruction alert. When flying toward the sun the OA system sometimes registers an obstruction. A false obstruction alert will cause the Mavic to follow the parameters you set in the application..hover, climb to avoid... etc. valuable time lost that has resulted in forced landings and lost Mavics.


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Instances in which the mavic will climb due to front sensor OA would be rare. Most RTH won't line up directly into the sun I'd wager. If anything the instances that I have seen were not caused by sun but possibly by a bug with OA that was similar to what happened with the P4P. OA on or off didn't matter. Will have to collect more data though to confirm.

 

[halley]

Most RTH won't line up directly into the sun I'd wager.

You would think so, but then remember that the best footage is often with the sun somewhere behind the camera, off to one side. You go fly out on a mission, you keep straying in the direction of great looking video subjects, and when your battery is low, where is home? Oh yeah, straight into the sun.

 

[gregw]

This guy tested the maximum flight distance on a single Mavic battery at around 67,000 ft/12.6 miles, all on max throttle in Sports mode... That's really quite impressive... I'm thinking that the Mavic seems to be pretty efficient at max speed...

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[f3honda4me]

This guy tested the maximum flight distance on a single Mavic battery at around 67,000 ft/12.6 miles, all on max throttle in Sports mode... That's really quite impressive... I'm thinking that the Mavic seems to be pretty efficient at max speed...

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No it was less efficient. Took battery to 5% after only 20 minutes. Then again maybe wouldn't go as far? I dunno math hurts lol.

 

[deltalimatango]

Thank you for sharing that. It was brave of you to admit that it was pilot error and the drone. At least you relized the mistakes made and shared them with the rest of us. [emoji122] [emoji113] [emoji106]

Kudos to you and fly safe...

SkyHigh Pyro Eye flying above

What's so brave about it? He made a simple mistake, and said so. He didn't set off a nuke or commit manslaughter. These are just luxury items that require a bit more attention. He presented a great story and it was a good read but I do not see the bravery in admitting a mistake. If people did that more often, it would not appear to be an anomaly.

 

[Logger]

No it was less efficient. Took battery to 5% after only 20 minutes. Then again maybe wouldn't go as far? ....

I guess that depends on how you define efficiency. If your talking about time running you could probably idle the mavic on a bench for an hour or more on a single battery

Range (as in distance covered) on a full tank\battery is a commonly used measure though and seems more useful than driving time achieved. That test though is pretty meaningless. Totally wind assisted and about as useful as doing a car mileage test only on downhill sections of road. . As they said the tailwind was 20 mph gusting some other (inaudible) figure. So whilst the Mavic flew no faster, throttling itself back to the ~42mph max GS or thereabouts, it would certainly be using less power than in nil wind. I would hazard a guess to say at least 1/2 the GS vector was provided by the wind so the Mavics TAS would have been barely 20mph! Had they turned around and tried to fly home at the half way point they would have been SOL.

A Good demo of a a critical battery autoland at 10% and how it works though. You can still control the pitch and yaw to get to somewhere good to land.

As he says at the end actually 71,400' or 13.5 miles & "bring on the criticism"! Very Impressive distance covered with a screaming tailwind. Not a terribly useful range test though and not much use for comparing Sport mode to P. We just need some nil wind stuff.

 

[f3honda4me]

I guess that depends on how you define efficiency. If your talking about time running you could probably idle the mavic on a bench for an hour or more on a single battery

Range (as in distance covered) on a full tank\battery is a commonly used measure though and seems more useful than driving time achieved. That test though is pretty meaningless. Totally wind assisted and about as useful as doing a car mileage test only on downhill sections of road. . As they said the tailwind was 20 mph gusting some other (inaudible) figure. So whilst the Mavic flew no faster, throttling itself back to the ~42mph max GS or thereabouts, it would certainly be using less power than in nil wind. I would hazard a guess to say at least 1/2 the GS vector was provided by the wind so the Mavics TAS would have been barely 20mph! Had they turned around and tried to fly home at the half way point they would have been SOL.

A Good demo of a a critical battery autoland at 10% and how it works though. You can still control the pitch and yaw to get to somewhere good to land.

As he says at the end actually 71,400' or 13.5 miles & "bring on the criticism"! Very Impressive distance covered with a screaming tailwind. Not a terribly useful range test though and not much use for comparing Sport mode to P. We just need some nil wind stuff.

True, you make good points.

 

[KiterTodd]

Can someone explain how "Return to Home- Me" works?

I thought that would manually update the home point to my location, each time I went into the menu. (static)
Can you set it so the home point is always where you are? (dynamic)

I may be misinterpreting this post, but have wondered the best way to do this if I'm moving with the controller and won't be back to the take-off point. Thanks!

 

[m0j0]

That was really a great example of a critically low forced landing. It is one thing I have never accomplished. Very interesting. Not a great range test though.


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