Which prop to buy?

I’m getting ready to order the SP 140 but still debating the 2 vs. 3 blade prop. I am looking at the quietest possible solution as I live in a very noise sensitive area. I am NOT as concerned about thrust as I had been flying the Atom 80 for years so anything would be an improvement over that engine (and it worked very well for me). I did fly the Moster for a while but didn’t really need all that power as I am a pretty conservative flyer. I get up to altitude and just glide around (I also paraglide). I believe the 3 blade would be a bit smoother??? but again, the noise (or any higher pitch) would be more of a concern. I am 170 lbs. and 6 feet. Any thoughts & experiences would be appreciated. Thanks!

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The higher the efficiency, the quieter the flight can be because the speed off the prop is little lower. A 3 blade is generally quieter in this case. You can also fly a little longer with it.

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Ppl tell that 3blade has a higher pitch where 2blade has a more muffled sound.
I therefore went with 2blade.
Tucker has a comparison video.

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I’ve only flown with the 3 blade. Feels super smooth and is not a high pitch sound. Even if it’s a slightly higher pitch than the two blade it’s still not a high pitch.


Thanks for all the feedback! I also saw a comparison from One Up Adventures and the pitch was definitely lower in the 2 blade but did enjoy the smoothness of the 3 blade. I can also understand that the 3 blade will spin at a lower rpm for a given thrust. The “flying longer” part is also a consideration. I may just have to eventually try both!

I just saw your YouTube site and some of the videos…quite impressive!

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I would like to show it here to everyone who hasn’t seen it yet to help.

The diagram shows very well how speed and propeller diameter relate to efficiency and noise.

Basically, there are subjective comparisons in the perception of noise and efficiency such as: from Tucker a good basis.

However, if you compare the SP140 and the Moster 185, the SP140 has a lower speed level and therefore the noise has a more positive effect because of the lower overall speed. Therefore, an analysis by Tucker with his Moster 185 is not directly applicable to the SP140. Because even 200 revolutions more causes a serious change in the blade noise.

Some electric ppg and trike aircraft have even lower speeds and are therefore very quiet and yet highly efficient thanks to the very well coordinated diameter and pitch range.

The diagram comes from Martin Hepperle.


Thanks so much for this…I was wondering how the different prop sizes and RPM’s would affect noise.