Only 7,000 rpm? Don't think I've ever heard of anyone flying successfully with such a low engine speed, so that's probably the first thing to correct. More nitro, a less restrictive silencer, a leaner needle setting, etc, etc, there are many things you can change here; I'm sure others will chime in with their experiences. Was our cool weather affecting the engine? (sure was nice in Orlando the last week! Sorry, had to throw that in!) Good luck with it, now I have to get on the stick with mine....