Prop Question 3D vs Precision

[airriley]

Ive been noticing that most reccomend a smaller diameter higher pitch prop for 3D and vice versa for percison. Can someone explain this to me? I thought the complete opposite would be true. Engine size I am talking about is 50cc. I was looking at a 23x8 until I saw on Troybuilt site that 22x10 is reccomended for 3D and 23X8 for percisaion.
Confused... Are we trying to keep down on torque?

[Jaybird]

Thats backwards for most applications

[yooki]

I assume the 23x8 is mentioned for precision because the larger diameter prop provides better downline breaking. A 22x10 will spool up faster for 3D. In reality both props would be fine for either application.

[dick hanson]

it is really a simple choice.
the 3D stuff requires the plane pull harderat lower airspeeds
this is where more power is needed .
smaller prop lets engine get deeper into max power .
the downline braking is not worth worring about.
On my 50's I run 22x8 at 7700 static (Mejzlic ) best instant power
for IMAC tho I prop it way down in static rpm -to high 6000 rpm - far more quiet yet still lots of power . My 22x12 ZM is extremely quiet.at 7000 static

[notorious_benny]

I use smaller diameter for 3D but same pitch, I like the motor to spool up quicker. So i use a wood to 3D and a carbon Mej to do precision.