I just watched a youtube vid of a guy's Spark crashing into the sea.



Basically he didn't seem to know what he was doing and went too far out over the sea at night. He lost connection and RTH kicked in but he didn't have enough battery to get back to land. At 16% battery the Spark tried to autoland which seems odd. He managed to get a bit further but didn't make it back. In the comments that followed it was repeatedly stated that he should have cancelled RTH and flown back manually in Sports mode as that would use less battery.  I'm not convinced of this so I'm asking here - for a given amount of battery can you fly further in Sports mode than you can in standard mode?

John

That has to be tested.
Anyway, if it had continued at 13m/sec, it could probably easily have made it.
I don’t know if crawling home is bad design or a necessity to avoid too large voltage drop for the motor controllers.

Well time vs batt drain.
Rotor craft do exhibit a large improvement in efficiency with forward speed since they then "surf" along.
Up to 50% at optimum cruise speed.

I seen a video on YouTube showing sport to be more efficient- don’t know how scientific or accurate but here is the link if interested

https://youtu.be/JpXAaA3y0ZQ

I think he would have been better to try cancelling and fly sport, max speed on RTH is 22mph 30mph in sport but more battery used someone needs to try it.

The problem here is not that speed is reduced in RTH it’s not it’s 22mph  if within 100 metres your speed is reduced to 14mph but this was obviously well outside this range, it was obvious that flight was initiated downwind so problem returning was as a result of wind.

Motor controllers (ESCs) have a cutoff voltage where they cease to work.
So maybe - just maybe, the slow speed is initiated to secure that none of the motors cut off. That would make it uncontrollable.
The lower the voltage, the higher current is necessary to hold the propspeed.

Interesting to see the drone travelling 29mph in RTH

dansmar Posted at 2017-12-18 10:40
I seen a video on YouTube showing sport to be more efficient- don’t know how scientific or accurate but here is the link if interested

https://youtu.be/JpXAaA3y0ZQ

Thanks for that link. Looks like a good test. If in doubt about the battery remaining I think I would opt for manual sports mode.

John