Basic Rocket Science

Here we cover some of the basics as to how and why a rocket works or fails, you should already of read about the components of a model rocket and understand the components of a model rocket.


Why are rockets sometimes not stable and fly in a random direction. well there are several things that effect the stability of a rocket. first is the speed at which it flies, without active stablisation there is a minumum speed for a rocket before it becomes unstable. Having said this even if the rocket is flying fast enough there is a possibility it is unstable this is down to the relation ship of the center of gravity and the center of pressure, lets expand on this below.

What is Center of Gravity?


What is Center of Pressure?



Why does the flame make the rocket fly well first have you looked at the subsections on Newtons Laws? you have but still dont see how the flame makes the rocket move, well lets not see it as a flame but what this is, is a lot of hot gas particals moving very fast, imagine each of those gas particals as the nut in the truck experiment in the subsections on Newtons law, so we have a lot of small masses being ejected from the back of the rocket at very high speed, well the equal and opposite reaction is the rocket moves forward. The heat of these particals and the flame has no direct efect on the movement, that is just a byproduct on making the expaning gases that we are ejecting at high speed.


Q: My Rocket flys all over the place why?

A: It could be a couple of problems one is it is not stable, the other is the fins are not in line with the body of the rocket,

Q: Why did my rocket not lift off the motor was big enough i did the maths?

A: You could have suffered from bernouli lock or the krushnic effect,

Q: What is Bernouli lock?


Q:What is the Krushnic effect?



This new page is a re-write of the old pages with usefull scientific formulas and explanations that are usefull to understand Rockets from the basics of Newtons Laws to more complicated equations used to design motors and predict their performance. The old HPR.ORG.UK web site contained a lot of out of date information that has now been archived, if you are looking for any of the old information and cant find it please contact us.

Information on this page can be used for educational purposes as long as this site is credited, the contents of this site can not be copied without our permission to other websites or for commercial gain.