Have there ever been any JATO bottles using only kerosene?
A RATO unit's purpose is to give a high impulse very quickly, it does this by combining a fuel with an oxidizer causing rapid combustion in a chamber, and forward thrust from the equal and opposite reaction. Kerosene is a fuel, but without an oxidizer you don't have a rocket, you have some lamp oil burning. If you wait until the airplane is moving then it's lamp oil burning in a wind, giving you no benefit.