I have had a great time working through my 40 hr Phase 1 testing. The performance of my Zenith CH750 STOL / Corvair 2.7 l is OK - not spectacular compared to my training in a C172 (but totally different plane). My Vy is right between 45 & 50 indicated - I rotate at 40 and climb out at 50 @ 500 fpm - good performance. My prop is a Warp Drive 2-Blade 68" ground adjustable that I set for a static rpm of 2850. Full power is close to 3000 rpm and I usually cruise at 2700. Cruise spped is right around 70. When I pull the power back it is seriously pulling back 25% to 33% of full throttle to get to 2700. Today I loaded up a 60# sandbag in the right seat and did some t/o and landings. That was OK. I loaded up another 60# (120# total) and my climb started to get a little scary - a little more close to the high tension wires and trees than I liked. In fact turning into the good stiff wind we had was the only thing that made me climb. I had another sand bag to make it 180# total but I wasn't that crazy. My plane empty is 850#, full fuel it is 1000# even. Max design weight is 1430#. I should be able to carry 430# of meat. I understand the basic concepts well but I'm no aerospace engineer. I am I getting what I should out of my prop? Engine?