Does anyone have any insight on why a 5045 bi-blade prop delivers more thrust than a 5045 tri-bla...

[G+_Mr ROKnBOK]

Does anyone have any insight on why a 5045 bi-blade prop delivers more thrust than a 5045 tri-blade prop (given all else on the quadcopter is the same)? This is happening on my KH250.

[G+_Art Miller]

So i think you are running into the same problem most model airplane people are having, most props in use are 2 blade, I believe this is related to fluid dynamics and how props/propellers work. Short answer is that when you disturb the air it needs to 'rest' a little bit before the blade takes another 'bite' of it, a 2 blade prop gives it that resting moment, a 3 or 4 blade prop really doesn't give the air that time to rest, so you are esentially trying to 'bite' into choppy air and you loose thrust. Though I would like to know what the difference is in thrust at low 'idle' speeds (ie do you need less power to hover with a tri blade vs 2)

[G+_Mr ROKnBOK]

Bill Michaels Art Miller Thanks for the insight.

 

Would I be correct in thinking that, since I'm having issues with a 5x4.5x3 (but not the 5x4.5x2), flying with 5x3.5x3 props might give better results (since it wouldn't be taking such large "bites" of air)?

[G+_Travis Hershberger]

Mr ROKnBOK Off the top of my head, no. But now I want to run it through some Fluid Elemental Analysis software to see for myself!

[G+_Mr ROKnBOK]

Carson Black Thanks for the reply and considerations.

 

I'm running the motors from RTFQ that were used for the KH250: 2205/2300kv.

The props I'm comparing are DAL blunt-nosed with the same length/pitch (5045)

 

I'll go back and re-watch the KH episodes that explain the prop/motor relationship for deeper insight.

 

Thanks, again.