I have a pitts that weighs 15lbs and it flys great. it does not have unlimited vrt with a 20x10 prop but it will hang on the prop. My brison only has 2 gal. of gas run in it.so it is not broke in yet. I also had a sig extra with a 2.4 in it and it had unlimited vert. The plane weighed 14.5 lbs