the_hefay Posted at 1-18 07:01
"As you did not add your own experiences with YOUR Mini2 yet, I was thinking maybe you're still not that sure about the height limit."
>Can it damage the motor to fly 20-25 minutes in such thin air? >Does putting the drone in cine mode place a limit on motor rpm's or does it just put a limit on flight speed?
Of course I do not know exactly for the Mini2, but DJI drones have become very smart over the last 7 years. While a P2 was more or less 'dumb', P3 in 2015 already started quite smart and later received lots of extra security features and controls which warn or already act before something bad happens. Such as battery to cold or voltage to low for full power or motor rpm to high/at it's limits, etc. So I think there won't be any immediate damage to a motor. Motor and battery maybe save also in these heights with the factory settings. But this doesn't mean there is no danger for our drones... If motor or propeller doesn't deliver sufficient thrust in a critcial situation and donre flips over or if the security feature says 'My motors or too hot, I will start to reduce power...' and the drone sinks just when it is near a the last peak to pass to come back home, we don't win much... ;-)
>Will the lack of air resistance cause over reving of the motors?
Easy to answer, yes it will, if air is too thin or wind/gusts to strong... ;-) You don't need 5000-6000m to get there, in the last weeks flying only around 2000m I encountered several dangerous areas, where it's easy to lose also a MP2. For example in narrow valleys or at sharp cliffs there's often a very strong wind directly at the edge which you should avoid. If you simply fly 40m above the edges it is often safe.
>Could a different prop size or shape help with this?
Yes, definitely. As the size is normally limited, you usually change the angle/the thread of each propeller or the number of blades. So it can “grab” more air at the same rpm (what would be too much for the motors in “thick air”). But for a hightech camera drone you need well balanced propellers from the factory and fitting to your propeller mount. You can’t use or just shorten other propellers like you can do for simple RC fun drones. Also foldable propellers are much more difficult to balance. Also more blades is difficult for foldable ones. For DJI P3 and Inspire there have been such propellers, I think also for P4. But I don’t know if also for Mavics or already for Mini2, but I haven’t really searched yet…
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