Test drive 3-blade prop?

[digidocs]

Hi VAF,

Does anyone know of a way to "test drive" a three blade prop on an existing two-blade RV-10? It would be awesome to see if it's noticeably smoother than the 2-blade Hartzell BA before going ahead with a big purchase.

Alternatively, maybe someone with a 3 blade prop would like to meet up for a day and we could each do a test flight with the other propeller. Might make an interesting Kitplanes article, too.

 

[eastonale]

Where are you? This would be fun.

 

[Ironflight]

When we started a round of prop testing at Kitplanes a couple years ago, we replaced the two-blade metal BA Hartzell on our RV-8 with a three-blade WW-300 series and gained a couple of knots plus about 10% ROC (you can look up the article for details). Except for it being on an -8 instead of a -10, it sounds like the experiment you want to do.

In terms of smoothness, both props were balanced to .01 or .02, and were remarkably smooth. I can convince myself the three-blade is smoother, but the Dynavibe says they measure the same. I kept the three-blade BTW - lighter, better performance…and just looks awesome!

Paul

 

[David Paule]

With good dynamic balancing, you can get a two-blade prop to feel very smooth.

Dave

 

[digidocs]

Mark---left you a PM.

 

[N890GF]

3 vs 2

I think the "smoothness" that comes with a 3 blade prop vs a 2 is the frequency and amplitude of the air hitting the canopy/fuselage. 3 "waves" of air per revolution vs 2 for similar amounts of power will result in a higher frequency but lower amplitude of buffet. Might feel like its smoother from a user experience standpoint even if the data says they're equally smooth.

I went with 3 blades because it looks cooler to me

 

[Canadian_JOY]

I think the "smoothness" that comes with a 3 blade prop vs a 2 is the frequency and amplitude of the air hitting the canopy/fuselage. 3 "waves" of air per revolution vs 2 for similar amounts of power will result in a higher frequency but lower amplitude of buffet. Might feel like its smoother from a user experience standpoint even if the data says they're equally smooth.

I went with 3 blades because it looks cooler to me

I have to believe this ^^^^ as well as perhaps some magic interaction with the number of prop blades being a multiple of the number of cylinders. I'm just guessing on this last part. On my C85-powered airplane I went from a 2-blade to a 3-blade prop and the difference in smoothness was very, very noticeable.