I have never under stood why you would want an onboard tank just to dump it after start up. That small amount of fuel will not do anything to your model if a line comes off, and in a crash you have a lot of other things that will make way more flames like lipos and large amounts of kero. I have been using an on board tank in all of my models sinece 2002 and have never had a problem with it, a model that has been un flown for a month or so still has the same amount of gas on board as when I put it away. I know this because in the in the frist few model I put a presure gauge in the model and it could sit all winter and not change.

John