Well...I did get my #2 HBKII with stock radio to hover in the basement inverted. I had to re-trim the heck out of it so that tells me I need to work on the setup...but it's do-able. Funny....the setup now hovers and flies good upright. Hit the idleup....all he!! breaks loose till you trim it out. I see I gotta work on BOTH birds too....I tried them both. Inverted....yeah, only from 100ft+ up. Need the recovery time. Something to mull over in your mind. Inverted out of the box???? Give me a break. You could do it but you better have a garbage bag with you to take it home in.