I don't understand the reasons for going to a 23x8 from a 22x8 on DL/DA 50cc size engines, particularly for 3D. It seems to me the rpm's would be down, but does the bigger prop provide more air flow over the control surfaces or what. It's probably Propeller 101 for a lot of you, but it's Greek to me.

try it and see.

myself i like a good wide blade prop like a MSC or a Mejzlik 22-8 for 3d.i prefer to keep the RPM's up and instant throttle response.another good prop i like is the Vess 22-A.now if you are running a tuned pipe the 23" props work better for me.

It might be that the 22x8 gives you a lighter load hence easier to spool up and a higher RPM. Of course something like a 23x6 (if it exists and would work) would be better since you do not need the extra pitch for speed. The so called 23x6 would give a lighter load and a bigger diameter assists in giving thrust. But I thought its 22x10 or 23x8 for a 50cc engine ...

For 3D it will both help and hinder. It gives more thrust but loads the engine down. It delays the spool up and that can be a problem with 3D. I will slow down the plane and make it quieter due to lower RPM. 23x8 gives more prop wash across the surfaces. It does NOT cool the engine down more, just the opposite. It heats it up due to the higher load of the larger prop.

I fly mostly 3D with some IMAC stuff. I find that the 22x8 is the best prop for instant thrust on the light and powerful 50cc engines. If you have a pipe you may want to go to the 23x8 to keep the prop rip down.