Has anyone tried the multi rotor pushers?
APC 12x4.5?

DON'T! The APC multi rotor props are not usable (for most aircraft) because of lower structural limits & lower rated RPM capability  

The 12" multi rotor props have a lower max speed rating than the normal electric props  The max RPM for the 12" Multi rotor prop is only 8,750 RPM.  The 12" Electric props are rated for a max of 12,083 RPM.   If you would like to try the math yourself check-out:

http://www.apcprop.com/v/html/rpm_limits.html


If you want to try a 12x4.5, take a 13x4.5EP and clip it to 12", try at around 9800 RPM - should be close.

If/when you get your new PAMPA Stunt News, I did an article that discussed prop speeds, Governor Range, Motor KV & Cell Counts.  There's a chart there that shows most all of the APC Pushers & their max rated speeds.

The 12x6 EP is a (roughly) 8600 RPM prop, the 12x4.5 (clipped from a 13" is a 9800 RPM or so prop.  If you are looking for higher RPM than that then not sure where you will find it.