What is a rocket stove?
A rocket stove is a low-tech, low-cost, highly efficient clean clean-burning stove. Compared with traditional open fires it is way more efficient. It gives off little smoke and uses about 80% less fuel. This stove uses small diameter short sticks and even leaves, twigs and brush. The fuel for cooking can be gathered quickly. The rocket stove is simple to build,
This simple stove is also a clever and efficient way to build a camp cookout. It is a simple structure that achieves high temperatures. An added bonus is that it generates little smoke. Because there is little smoke these stoves are much safer for everyone avoiding harmful emissions. 
Why is it called a rocket stove?
Because of the construction, the heat is “sucked up the chimney/burn tunnel and the roar that results is where the name comes from.
How does a rocket stove work?
The stove consists of a simple combustion chamber. Air is sucked up into this combustion chamber. The small air vent reduces oxygen intake therefore the stove uses less fuel and the fuel burns cleaner. This super-heated hot air rises up the insulated chimney over which the cooking takes place. This design results in almost complete combustion of the fuel.
Simple to build
The stove consists of a small combustion chamber, an “elbow “ and an insulated chimney. Hot air is sucked up the chimney. You can include a small grate on which to build your fire which can add to the efficiency. (see illustrations)
Fuel efficient
With a rocket stove, you can use small amounts of fuel and only the tips of the twigs are burned. This avoids waste. One of the best features is the reduction of smoke. The stove uses up to 80% less fuel to cook your food. Biomass fuels release a lot of air pollution. This stove emits little smoke and burns very efficiently.
It can be relatively portable and is certainly help when cooking needs to be done during power outages and load-shedding