Motors: Facing Up vs. Facing Down

[Jim Schultz]

So I have been wondering this for a while now. I would say the majority of copters are using motors that are facing up(pulling?), though there are some copters that have the motors facing down(pushing?). What is the difference between this? Is one more efficient than the other?

 

[Pumpkinguy]

I would say pushing down is very, very minimally more efficient as the props are not pushing air on the arms.
Cons. Props more likely to get into the shot. Way More dangerous to hand catch.
Possibly less stability because the center of gravity is higher in relation to the props.

 

[Old Man]

My first thought upon reading the thread title was "depends on what she looks like", but that wasn't quite what you were looking for......

I would think props up would be a skosh more efficient. Cleaner air ahead of the blade's incoming side.

 

[Jim Schultz]

That is what I was thinking, but I didn't think about the camera part... That brings me to my next question: what if you were to have a copter (say a hex) with 2 motors down, 4 up? Would that affect flight?

 

[SleepyC]

That is what I was thinking, but I didn't think about the camera part... That brings me to my next question: what if you were to have a copter (say a hex) with 2 motors down, 4 up? Would that affect flight?

Not, I have seen several like this, and there is a thread where if you search for it here on MRF where a guy asked if he could run 18" props on a 700mm Hex if he ran the motors like that which would make the prop tips overlap by 1/2" but since they were 1 up 1 down, it allowed it.