TUKKUS, As you can see, everyone has their own ideas on how to break in an engine. All you can do is to do what you feel is the best. There is no clear cut answer. I personally don't bench run, and never have. There is nothing wrong with it, well, ok, I have seen one guy do it wrong and he ruins them so fast it isn't funny, but thats another story. If you break them in while flying, you may have to deal with a couple deadstick landings at times. If it is a plane you don't want to deal with deadsticks on, run it a few times and make sure it is tuned propperly. At any rate, have fun! It all works out and neither way is the "correct" way.