Blades/propellers - power optimization - drone hovering

[udib]

I wonder what is the best figures for blades/prepellers - assuming I am trying to optimize battery life and my main usage for the drone is hoovering.
I can not play with the arm length.
I do consider 4 blades over 2 blades at the same propeller - not sure if it will help.
Any feedback or idea is appreciated
thanks , udi

 

[Rx7man]

There are going to be a lot of variables here... typically slower things are more efficient, but with a lot of exceptions.. motors will have different efficiencies as well.. You may have to empirically test several setups and watch your current draw.. the setup with the least current draw while hovering is going to have the longest battery life.. Downside to bigger, slower blades is it will be less nimble, as well as the bigger, slower blades will require more gearing and be heavier.. It's a balancing act :)

 

[CWatters]

In general a 2 bladed prop is more efficient than a 4 bladed prop. That's because the tips of the blades are less efficient then the main part of the blade. Single blade props have been used for some racing model aircraft but they require careful balancing and can cause other problems.

 

[Tom.G]

Here is one popular, low cost, design. The "high cost" design I've seen is where the pitch starts out high near the hub (sometimes also with increased area) and decreases toward the tips.