3 blade vs. 2 blade rule of thumb
 

Hi all.

What's the rule of thumb regarding "downsizing" to a 3 blade prop, for the diameter of the prop?
I have a Super Tiger .90 that I've always used successfully with 14/7 propellers.

What would be an appropriate 3 blade equivelant for this engine?
Also, other than ground clearance issues, are there other tradeoffs/benefits to consider with a 3 blade-er?

I'm considering it for a Sig 3-D Mayhem.

Thanks.

RE: 3 blade vs. 2 blade rule of thumb
 

there are formulas but basically just take diamater down and inch...

do a search, has been discussed many times.......
keep an eye on performance...some people feel that the 3 blade props are very inefficient

RE: 3 blade vs. 2 blade rule of thumb
 

Here we go again :D

RE: 3 blade vs. 2 blade rule of thumb
 

thats why I said "some" people ....;)

the 3 blade v 2 blade discussion ranks up with the "which is better, Futaba or JR" etc. etc. etc type threads......


I really want to try a 3 blade prop.....just to find out for my self... they just look cool!

RE: 3 blade vs. 2 blade rule of thumb
 

OS is better than Enya
Futaba is better than JR
Wildcat is better than Byron
2 blades are better than 3
Wood is better than fiberglass
Balsa is better than foam
Oracover is better than Monokote
SolarTex is better than Coverite
Scratch builders are better than ARFers
Blades are better than Serengeties (sp?)

My dad can beat up your dad

etc. :D

did I miss any?

RE: 3 blade vs. 2 blade rule of thumb
 

Bosch, I don't know why you'd use a three blade prop! Even if it were more efficient (which it's not :-) you couldn't find a three blader with fun fly pitch. Stick with the two blade props. Exeter Acres got it right... one inch down on similar prop (ie APC to APC, MAS to MAS)

RE: 3 blade vs. 2 blade rule of thumb
 

You forgot:

Bourbon is better that Scotch

RE: 3 blade vs. 2 blade rule of thumb
 

I have always read that you have a choice of reducing the length by 1" or reducing the pitch by 1" works. Being that the most practical reason to go to 3 blade is to get more ground clearance while trying to keep similiar performance then the reducing the length method comes into play[8D].

RE: 3 blade vs. 2 blade rule of thumb
 

Some people go to a 3 blade prop just for the looks.

RE: 3 blade vs. 2 blade rule of thumb
 

Hey -- Scotch is much better than bourbon.

For props in the mid-size range (10-14") , & going from 2b to 3b, -- reduce the diameter by 1" for the same pitch, or maintain the same diameter & reduce the pitch by 2". More or less -- assuming that the manufacture is the same, -- assuming that the blade shape & aspect ratio are similar, -- assuming that the material & blade thickness are similar -- otherwise suck it & see.