In order for any rocket to fly, it must obey some basic rules of physics. No rocket can escape the cardinal rule that the center of gravity must be in front of the center of pressure.
Center of Gravity
The Center of Gravity or Cg is the point that behaves as if all the mass was concentrated in that one spot. Simply put it is the point at which you could balance the rocket on your finger. The Cg is also the point around which the rocket rotates. This becomes very important for the rocket's stability as you will soon see.
Center of Pressure
The Center of Pressure or Cp is similar to the Cg. The Cp is the point at which the forces from the air pushing on the vechicle seem to be focused.
What is a Cg or a Cp?
Basic Rocket
Why Does This Matter ?
When a rocket is in flight, the force of the air pushing on it keeps the Cp behind the Cg. This is important because the rocket is pushed by the force of the exhaust coming out the back. If the Cp was in front of the Cg, the rocket would want to spin around (so that its back was pointing forwards).. However, because the exhaust is always pushing the rocket forward, it spins around again and again... and you get the picture from there.
Fins
So now that you know all about Cgs and Cps, it should make perfect sense what fins are for.
Still a little confused? The fins are extra surface area near the back of the rocket. This brings the Cp further back on the rocket without significantly moving the Cg..
Calculating Cp
Calculating a Cp is rather involved. The easiest way to do it is by using Barrowman's Equations, although these are still fairly complicated. I was going to explain them, but I found a site that does a better job than I could ever do.
The UAF Student Rocket Project builds and flies sounding rockets with help from Wollops Flight Facilty.
Our latest mission, SRP4, is a student designed and built payload. It will be carrying a science instrument designed by students and professors at Toyama Prefectual University in Japan. Our goal is to measure the D-region of the ionosphere.
SRP4 will fly atop an Orion sounding rocket motor that will be supplied by NASA's Wollops Flight Facility.
We expect to launch from Poker Flat Research Range in March of 2002.
Ever since I was little I was amazed at the ability for a machine to fly. I have always wanted to explore ideas of flight and be able to actually fly. I think I may have found my childhood fantasy in the world of aeronautical engineering. The object of my paper is to give me more insight on my future career as an aeronautical engineer. This paper was also to give me ideas of the physics of flight and be to apply those physics of flight to compete in a high school competition.
The panel has held a number of full meetings and numerous subpanel and individual member meetings, and has submitted three written status reports to the NASA Administrator. Although NASA has not yet formally responded to these status reports, actions have been taken to implement most of the committee recommendations. NASA has held several meetings with the committee to discuss and review the status of the response to the recommendations. The NRC membership and a summary of the panel responsibilities are provided in Appendix
The piston is pushed upward by the flywheel's momentum, compressing the air/fuel mix. 3. Combustion: As the piston reaches the top of its stroke or TDC, the spark plug fires, igniting the mixture. Due to the high compression of this mixture, it is very volatile and it explodes when the spark is introduced. This pushes the piston downward and produces power.
According to Miller, Ron. The History of Rockets. N.p.: Grolier, 1999. Print. "The forces of action and reaction, which propel the rocket forward, occur the moment the fuel is burned-before the exhaust leaves the engine." (Miller 10). the combustion within the motor is burning the fuel (reactants) causing the exhaust (products) to leave the motor pushing the rocket up.
“In a fraught fiscal climate, NASA should focus on what it does best and on what offers the best return on investment. Solar system exploration meets both criteria: the U.S. has long led the interplanetary charge, and the resulting scientific benefits have come at a relative bargain. This year NASA 's planetary science program cost about $1.5 billion -- less than what NASA spent designing a congressionally mandated rocket, the Space Launch System, which appears more likely to satisfy aerospace contractors than to aid the cause of space exploration. Such directives from lawmakers all too often land in NASA 's lap without the funds to carry them out (To The
Wie, Bong. HAIV Mission Architecture. Digital image. Space.com. TechMediaNetwork, Inc., n.d. Web. 09 Apr. 2014.
Are we allotting enough funding for aerospace research? At the present time, significant progress in aerospace research will not be made for a long time. It is sad that we don’t place more urgency on such an important field. Yes, there is still research being conducted in the field; however, limited funding prevents significant advancement. The benefits derived from aerospace research should provide enough justification for investing more money in this area. The benefits are not exclusive to sp...
According to Newton’s third law of motion, forces always act in equal but opposite pairs. Another way of saying this is for every action, there is an equal but opposite reaction. This means that when you push on a wall, the wall pushes back on you with a force equal in strength to the force you exerted. The forces exerted by two objects on each other are often called and action-reaction force pair. Either force can be considered the action force or the reaction force. Action and reaction force pairs don’t cancel because they act on different objects. You constantly use action-reaction force pairs as you move about. When you jump, you push down on the ground. The ground then pushes up on you. It is this upward force that pushes you into the air. When a bird flies, its wings push in a downward and a backward direction. This pushes air downward and backward. By Newton’s third law, the air pushes back on the bird in the opposite directions, upward and forward. When you walk forward, you push backward on the ground. Your shoe pushes Earth backward, and Earth pushes your shoe forward. Earth has so much mass compared to you that it does not move noticeably when you push it. Also like a rocket launch, when the rocket fuel is ignited, a hot gas is produced. As the gas molecules collide with the inside engine walls, the walls exert a force that pushes them out of the bottom of
Kinematics refers to the motion of objects without taking note of the forces that act upon that object, while projectile motion is a form of movement where an object is thrown from the surface and travels along a curved path that is just controlled by gravity. As a result of neglecting air resistance, gravity would be the only force affecting the system and thus, the acceleration due to gravity would only affect the vertical displacement and vertical velocity of the object. The horizontal component of the velocity remains unchanged throughout its motion. In this experiment, the time of flight and range of the object were investigated by using a projectile launcher. The ball was either launched by short range or medium range, which is more powerful than the short range (ball travels
"National Aeronautics and Space Administration - Marshall Space Flight Center." NEW FRONTIERS ::: JUNO. NASA, Web. 01 Apr. 2014. .
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Tate, Karl. "NASA's Mighty Saturn V Moon Rocket Explained (Infographic)." Space.com. N.p., 9 Nov. 2012. Web. 18 May 2014.
The parachute of the bottle rocket deployed. It worked because it wasn’t “stuffed” into the nose cone. If it was, however, it would be stuck in the nose cone and not deploy. Even though the parachute deployed, it didn’t help the rocket decelerate too much. It was most likely because the parachute wasn’t big enough. If the parachute was made larger, the time of flight for the rocket would’ve increased.
"Johannes Kepler: The Laws of Planetary Motion." Astronomy 161: The Solar System. Web. 17 Dec. 2011. .
(Source K) Flowers, Sarah. “Understanding: Space Travel.” Rev. of Understanding: Space Travel. PoQuest. N.p., Aug. 2000. Web. 12 Mar. 2012. .