ORIGINAL: raydar
8800 to 8900 is optomistic with a dle 20 on a xoar 17 6 , not saying not possible but I have a dle 20 and have had a couple of other 20cc motors and 8500 rpm seems to be impossible with perfect timing and peak tune. If I could run 8900 with a 17 6 xoar I would be fitting a 18 6,not likely.
I get 8800+ with all my (5) DLE20 on APC17x6 GF nylon props.
I fly near New Delhi with 260M ASL and 25-35*C ambient temps.