Does anyone know the correlation between hovering time, flight time, and battery life on a copter? How much of the battery will be used just to hover and how much is used to to fly over a distance?

Thank you!

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That's unfortunate that it was removed :( This sounds very helpful and I'm looking into it right now! Thank you so much, I need all the help I can get!

Wow. Like bees to honey here. Amazing what a pretty profile picture can do :)

In the mean time...

Steady forward flight will yield better efficiency compared to hovering as far as energy consumption rate.  As others have stated, doing aerobatics will cause your power usage to increase.  I think the 2:1 maximum thrust to hover thrust ratio is a more than adequate control headroom.

Thank you, Gary.  You're too kind.

Hey Brad, I've been pretty well, you?

Making some decent progress on all this stuff, particularly the heli dynamic controls. And I met another guy that has complimented your teachings, but more on the heli side.  I've learned that the #1 thing holding back helis from getting better efficiency, is much that our Ct/Sigma is too low.  I'm already turning the rotor about as slow as I can while still having good control.  I really need narrower blades, but they don't make any.  Stuck with what's available on the market.  He also explained that, these symmetric blades aren't nearly as bad as we'd thought.  The cambered airfoils aren't really much better in practice.  Blades with taper and twist are really only efficient in a narrow flight regime, and then can be very wrong outside that.  And we spend most of our time outside that.  The asymmetric blades have a higher peak Cl/Cd point, but it's sharp, and the typical NACA 0012 has a lower peak, but is much flatter.  Considering the real inflow velocity profile across the rotor disk in reality, this isn't such a bad thing.

I made a mapping heli that I think is doing well.  1020mm rotorspan, 3.2kg, 480W hover.  I haven't circled back around to get FM yet.

Actually, you'll have better efficiency in the direction of 1:1.  But this is tickling the dragon.  Go too far, and it won't fly well.

And the forward flight efficiency, only works up to a certain point.  I don't think anybody has studied it rigorously on multirotors yet.  

We're probably talking 5-10 m/s, and then you'd loose efficiency after that.

Ok, I'm getting FM of 34, assuming a motor efficiency of 75%, but not including the "control headroom" you previously assumed, which, I'm not sure I agree with why that's included in the calculation.

"unless proven to be less efficient than another solution."

A larger quad with larger motors and props is more efficient than a hex. It is expensive to build, but much much more efficient. Look at the steadididrone qu4d x. 1 hour flight time and 8kg payload capacity. but also super expensive.

Haha... True dat... I think if I'm looking for some answers I'll use my pretty face next time


This looks awesome, one of the highest payloads I've seen so far. I think this is something we would like to use somewhere in the future for sure... just for testing purposes though I think they want to spend a bit less than that. Thanks again!


Thank you Hugo!

Good to know about the forward flying. As far as the ratio, I think I got confused because I've read from other sources that the thrust requirement should be twice the weight of the copter. So if that's not true, then great! Thanks for all of your help!

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