"non-square" quads - ok or not ok?

I've seen a few "X" airframes around that appear to have a wider space between the front props than the rear. (eg: steadidrone)

This seems strange to me, as ideally you'd want a totally square prop layout so you can place the FC right in the centre for more predictable handling.

I understand that the wider front props is usually to assist video, but what about the performance impact? How does a quad handle when the prop footprint is not completely square? I thought you had to be "strict" with the square footprint?

Also, I'm sure some even have a shorter "wheelbase" as well; ie the distance between the front and rear prop "axles" is less than the distance between the left and right props.
 

kloner

Aerial DP
there are several reasons they change up the frames layouts. wider in the front and a little back helps get the props out of frame. stretching them back helps let you move cg back which makes it happier in fff, gives it more leverage to get the *** end over cg to make it go faster as well.

the xy layout is the later you ask about, there certainly different

i've flown em all and love the way a discovery is laid out. shes a keeper
 

Electro 2

Member
Keep in mind you'll probably have to adjust Pitch and Roll PIDs differently since the frame moments are not symmetric. It may fly with them matched, but an optimal set-up will have them individually tuned.
 

matwelli

Member
where the issue is, if the spacing between the front props is, for example, greater than the spacing between the rear props, is Yaw causing roll in the airframe, due to the motor pair that is closer to the frame, having a greater affect on roll than the ones further out

This also affects the V8 and V6 layouts

A really good controller, tightly tuned in attitude mode will mask the effect, but the best way, if you have a controller that can be custom programed, is to adjust the yaw mix , less on the rear motors, untill it yaws without rolling
 

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