What do you think of my project?

3D Printing
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1

What do you think of my project?
https://www.youtube.com/watch?v=DF2FmNGvRjE

2

Nice, to reduce noise the propellers need to have a non divideble number of blades, like 5,7 or 7,8. otherwise they will generate in strong interference waves.

3

@Hans_Franke that’s really useful information!!! Thank you!

4

@Engineering_Nonsense It’s the same lesson Antonow did learn from the AN-20 (4/4 propeller blades) when they designed the AN-70 (now 6/8 but also dfferent shapes)

Maybe check here: https://en.wikipedia.org/wiki/Contra-rotating_propellers#Advantages_and_disadvantages