Why is a solid rocket engine smaller than a liquid one?
Third question: can not. For the rocket engine (except for fireworks), grain shape is very important, it determines the rocket engine thrust, working time and thrust change. Not a little shake on the loose
The first question: at present the highest calorific value of fuel is hydrogen, and hydrogen into solid fuel is not practical. So the hydrogen fuel specific impulse over the current all kinds of fuel. The second question: can not. In order to ensure the maximum speed to the combustion of fuel, fuel and oxidizer must be mixed, can be mixed in liquid rocket engine combustion chamber but, the engine must be mixed combustion in solid surface. If the oxidant and fuel separation, will greatly limit the burning rate.
