# DJI spreading wings 900 propeller size

I need to know the size (length and chord) of the UAV spreading wings s900 propeller. It should be 1552/1552R and the only info I was able to find was this size: 15×5.2inch (see here). I found that the 15 inches is diameter, so the length is half of that. However, 5.2 is a pitch, and I cannot understand how do I get chord size from that.

P.S. I don't own the drone. I only need to know the size, so I can't measure it myself.

Here's a picture of the blades. I rotated it and measured it with an image editing program. The lower blade is 918 pixels long and 215 pixels wide at the root, 76 pixels wide at the tip.

If each blade is 7" long (allowing for the hub), 1" is 918/7 = 131 pixels.

That makes the root chord 215/131 = 1.6"

And the tip chord 76/131 = 0.6"

The taper doesn't appear to be straight, but I'd guess that only reduces the area by a few percent.

Short answer: You cannot from the stated dimensions

Pitch is more about angle of the blades (it's a bit more complicated, and is also an outdated calculation, see "advance ratio", from which you could possibly get chord info with enough math).

The chord width of the blades is independent of pitch (see "collective pitch helicopter"), a variable pitch propeller does not also change its chord when changing the pitch of the blades.

Why do you need to know this information? I assume you're doing lift/static thrust calculations and need blade area? You could work backwards from current/power figures but it will be an approximation at best.

• Thank you for your answer. Yes I am doing some research and need to calculate power required for flight and hover in different conditions. Right now I have approx. data but having real shape would help for better results. Maybe somebody will know the real chord value.
– Ruli
Dec 9, 2021 at 14:03