2 or 3 bladed

[flightexpress]

I'm looking at getting a powerfin prop, but was wondering if I should get a 2 or a 3 bladed prop..Would like any help I can get......Kurt

[MattPearson]

We need more info in order to help. i.e.
Engine
redrive ratio
aircraft type
diameter limitations

[birdy]

I'll never go back to 3 blades, solong as two can handle the power.

[MattPearson]

Amen to that!

[bones]

I'll never go back to 3 blades, solong as two can handle the power.

Birdy what did you mean about that quote, i'm about to get a new prop and was wondering about going to a two blade or stay with another three, and i rang up to get a quote and the guy was trying to talk me into a four blader. :eek:

[birdy]

I'll ring ya tomorrow nite Bones,and tell ya wot I know bout props.
Head'n off to camp now.
But from wot I found, the right two blade setup is better than the 3.

[flightexpress]

I called Power Finn and they said that a 2 bladed prop would be the best...I'm not to sure but that is what I'm going to get.......Kurt

[birdy]

Sorry Mark,you'll have to ring me,I lost your number.

Bloody ell,I'v passed the 1000 post mark,look out Ron A,I'll beat you at something yet.

[Dale Young]

I've had both 3 and 4 , wood and composite, I personally like the 3 because it's quite a bit more smooth and provides better clearance. The 3's are a little less efficient, but the trade-off was worth it for my application. By the way, I'm currently using an Ivo, but the Airplasts look interesting.

[Doug Riley]

Props and rotors are much the same. Two-bladers produce some vibrations that you can't eliminate altogether. Three-bladers are noticeably smoother.

For a given thrust, a lower disk loading means you are accelerating MORE air but LESS intensely, which turns out to be more efficient. With two blades instead of three (each set at optimum pitch for the aircraft's speed range), you can run more diameter without overloading the engine. That's why a 2-blader will often (not always) be more efficient.

Sometimes this doesn't work out in practice. Gyros have diameter limits imposed by the overall height of the machine and/or the RPM at which the engine puts out its power. A 2-blader that's limited in diameter may have to be pitched so high that you get a lot of stalling near the blade roots. This will show up as poor low-speed and climb performance, with a noticeable performance increase as the machine picks up speed. In that case, a 3-blader (with less pitch) may actually perform better overall.