Rocket stoves are small efficient stoves that can produce a hot flame with only a few small pieces of wood. The reason it is called a rocket stove is because when wood is added to the fire the flames create an internal draft. As the draft is created, the fire begins to produce a jet of fire coming through the stove pipe. The stove flame eventually becomes so hot that it produces very little smoke. The stove should be able to produce a hot continuous flame that will lick the bottom surface of a pot or pan placed on top of the stove.
See how to make this cool project below, this could be a great garden piece with an added bonus, it can cook meals or make water safe with a few sticks