4 inch propeller musings

Looking around for alternative props to try on my Chimera 4, there appears to be only the one type available ( Nazgul 4030 two blade ) designed for 1mm motor shaft fitting.

However there does seem to be a variety of 3.5 inch three bladed props available - anyone have any experience with fitting slightly smaller props with more blades ? ( Or am I going to be first ? )

Yeah, I put some 8 blade 3.5" props on a 5" quad. Real grippy, slightly higher hover throttle, but no top end speed. A lot quieter than tri blades though

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I’m using these ones:

3 blades but lower pitch. My hands on experience is almost the same flight time but more stability.


Thanks - I’ll give them a go :+1:

A bit late to the party here, but I have plenty experience of experimenting with this sort of stuff on planes/wings.

Generally you can get a rough idea of thrust by looking at how much air they shift. 4 inch X 3 inch pitch x 2 blades = 4x3x2 = 24. 3 inch x 3inch pitch x 3 blades = 3x3x3 = 27. So theoretically a 3 blade 3" prop could be giving more thrust than a 2 blade 4". There’s drag and other factor to consider, but…

Have a look here: eCalc - propCalc - the most reliable Propeller Calculator on the Web
I have a premium sub, but the free version is good enough. Just pick a random motor that looks roughly in the right ballpark, a battery size and a generic 30A ESC or similar, then start tweaking the prop dimensions to see what effect it has on thrust and power/amp draw. It’s designed for wings, but you’ll soon start to get an idea of what sort of props might be feasible.

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I can bring this thrust meter to The Big Meet if anybody wants to test some of their kit on it


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This guy tried tri-blade on geprc baby crocodile 4 and seems to like it.

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In the brief 26s flight with these before I crashed it ( my fault - lost orientation and flew into the ground - hard ) they seemed to work well Emax Avan Scimitar 3.5x2.8x3

They bend well…

…but as I also broke the arm on the drone further testing will have to wait until I get a replacement bottom plate

That would be fantastic Steve. What would I need to bring to be able to test my motor and prop combo? I have a brand new spare motor and props but would I need anything else?