title_body: Do flexible propellers affect multirotor efficiency? There are a wide variety of materials and methods for making the propellers used on drones. This leads to certain propellers having different characteristics than others. Some propellers are more flexible than others and I am wondering how that would impact the efficiency of a drone?
upvoted_answer: It's really a challenging question to answer because flexible and stiff propellers both have their advantages and disadvantages in terms of efficiency.  
  
  Flexible propellers are typically lighter than stiff propellers, so they spin-up more efficiently than stiff propellers.  On the other hand, when a propeller is spinning at higher speed, a flexible propeller will have a tendency to flex upward and flatten out vs a stiff propeller that is designed to resist flexing (stiff propellers will still flex, but not as much as a flexible propeller).  With a flexible propeller, this could result in a scenario where you have more throttle to give, but the drone won't go any faster.  To some degree, you might also notice that the drone is less controllable - might not take a corner as well as a stiff propeller would.
  
  If you have a lower powered motor, a flexible (lighter) propeller might be your best option because you may never reach the point where efficiency is an issue.  However, if you have powerful motors, and your desire is for speed, then a stiff propeller will probably be more efficient at higher speeds than a flexible one.