Chicken Hoppers feed to the last drop, keep the engine lit. Problem with them leaning out during the flight, if uniflo is not used. Guess that shouldn't be an issue with uniflo. I've used these tanks a bunch. So far no leaks. The engines I use have not responded well to uniflo, so, I've run muffler pressure to the fill tube (no uniflo). A great sport run, too much rich to lean variance for an excellent stunt run. Solves lots of problematic engine behavior (at least for me) such as leaning out in outside maneuvers and cut-offs when pulling tight loops or jerking the plane around like a jerk.