I just got the F-18B "NASA" and absolutely loving it! I have the major airframe nearly completed. All it needs are the trailing edge flaps, then allI've got to do is put the cockpit in it. As for the tail heavy question, my dad has built a ton of them and never had to add any weight to get it to sit on all three legs. But then again this is the same guy who told me that it had bad fit problems (and I haven't had any...). Good luck. I hope yours turns out nicely.