I built one a few years ago. It's a neat looking plane but I was never able to get mine airborne. Mine weighed about 5.25 lbs. and had the Kress Fan with a 7.5 K&B in it. When I was building mine I noticed an error between the plans and the instructions in regards to the incidence on the stabilizer. The instructions called for one incidence and the plans called for a different amount. I used the amount on the plans which was less than the instructions. Kress claims well over 6 lbs. of thrust at 22,000 RPMs which on 35% nitro I was able to acheive. If I were you I would contact Zeroli and ask them about it. Good Luck.