hello, I built a 1.20 stinger (lanier) w/41cc us engine flew sluggish with zinger 18x8 and now I have a APC18x12 whitch flies alot better, but it feels heavy,rpm is 7000, and it weights a whoping 20# with fuel.
I'm thinking on changing that prop for a 20x10 Menz!
what should I do to make this airplane feel less sluggish

Thanks,
Fernando,