Once ignited, is the thrust from a model rocket engine uniform (constant over time) or does it vary during the engines burn?
-Yes, thrust of a model rocket varies during the burn time. At the beginning of the burn, there is a spike in the thrust, called the pulse. This is a short period of time of high thrust. Soon the thrust decreases and levels out at a much lower thrust than the pulse. This is longer lasted than the original spike. Thrust then stops completly because the fuel has been burned up. During this time the delay charge is burning, which releases tracing smoke. Then finally at the end of the delay charge is a short, small burst of thrust. This is created by the parachute charge (aka ejection charge). 2. Once ignited, can a solid propellant rocket engine be turned off? -No, solid rocket engines can not be turned off during the burn. Stopping the rocket is not necessary in most cases, but when this is a necessity, a liquid or hybrid engine is used. These types are able to be stopped because the fuel and the oxidizer are stored seperatly, and then pumped in to the combustion chamber. 3. A: What caus
