How much power is needed to hover ? (REVISED!)

– given a certain electrical setup that can generate a certain power, what is the maximum thrust that we can achieve ?

– can a human-powered aircraft be built ?

– can I tell the expected thrust generated by a copter simply by knowing the power it consumes and vice-versa ?

– are larger propellers really more “efficient” ?

– which multicopter configuration is more efficient:  tricopter ,  quadcopter ,  hexacopter or octacopter  ?

– I heard that for every gram of mass I add to my multicopter, the flight time will decrease by 1 second, can you put any sense in this ?

– and many more…

PLEASE NOTE THIS A REVISED ARTICLE ( 10/30/2015)

http://www.starlino.com/power2thrust.html

• Bart, can you please elaborate on how you calculated that battery-size-sweet-spot?

• I may disagree with Brat last answer. Battery power release is not linear with voltage drop (highly dependent on the electrode surface and quality of quasi-polymeric electrolyte) also the higher the copter weight (due to heavy battery) the more load no the motors. Thrust - power consumption curve is also not linear for any motor, so with increase of the battery size you may end up in a shorter flight time if motor - ESC efficiency low and if your battery have low grade polymer ionic permeability (no way that you can find it out from manufacturer).

• - yes

- depends, for the highest theoretical flight time, your battery should be 2x the mass of the copter without battery (so 66.6% of your total weight). Adding more battery from that point will decrease your flight time. In practice, about 50% of your total weight in battery will give you close to the longest flight time

• Moderator

– are larger propellers really more “efficient” ?

– which multicopter configuration is more efficient:  tricopter ,  quadcopter ,  hexacopter or octacopter  ?

– I heard that for every gram of mass I add to my multicopter, the flight time will decrease by 1 second, can you put any sense in this ?

• The article was revised 10/30/2015 the coefficients are now in line with classical theories.

• Starlino, it's a good explanation  but you may want to check your measurements or calculations again. Usually the ratio between electrical energy coming from the battery to kinetic energy into the air < 100%. Otherwise you may have found the perpetuum mobile :)

ESC+motor usually have an efficiency of around 60 to 80% and for the propeller the same. Perhaps one of your constants has an error?

• Nice explanation. Good job. A online app or excel spreadsheet would be even more helpful.