Testing video of 50 N-bipropellant rocket engine
Hybrid rocket motor test -https://youtu.be/4uAmlIaUxv4

Bipropellant liquid rocketsgenerally use a liquid fuel, such as liquid hydrogen or a hydrocarbon fuel such as RP-1, and a liquid oxidizer, such as liquid oxygen. The engine may be a cryogenic rocket engine, where the fuel and oxidizer, such as hydrogen and oxygen, are gases which have been liquefied at very low temperatures.

Liquid-propellant rockets can be throttled(thrust varied) in realtime, and have control of mixture ratio (ratio at which oxidizer and fuel are mixed); they can also be shut down, and, with a suitable ignition system or self-igniting propellant, restarted.
~education propose video