HCRCflyer,

Whatever prop you use for the ST 2300, try to keep the RPM somewhere around 8200-8500. That is where the torque seems to be the best. If you get in the 7000's, you will definitely notice a drop in power and a 17x 12 may be a little too much prop. I used this engine on several planes and the props I liked best where the APC 16.5 x 12 and the 17x10. Good luck and keep us posted.

Emory.