Flight Technology: Aerodynamics Key Words: Thrust, Lift, Drag, Nose Cone, Rocket Body, Fins, Stability

Aerodynamics of Rockets Aerodynamics is the science of how an object reacts to its motion through air. The same four basic aerodynamic forces act on both rockets and airplanes: Thrust Weight Drag Lift

Thrust The force that propels the rocket or airplane forward is thrust. Thrust is created by the engines of a rocket or airplane.

Lift In an airplane, aerodynamic lift is the force that overcomes weight (gravity) and allows it to fly. This lift is created by the airplane's wings.

Drag Any object that moves through the air will be slowed down by the air resisting the object's forward movement. This is called aerodynamic drag. The smaller the surface area moving against the air, the less drag will be created. As surface area increases, the force of drag will increase.

Nose Cones The nose cone on the front of the rocket is like the point of an arrow. The slightly rounded cone is better than a blunt end. Yet it produces the greatest amount of drag of these three designs. The pointed cone greatly reduces drag, but it's not as effective as the slightly rounded shape. The slightly rounded nose cone creates the least drag when flying at subsonic speeds.These are speeds below the speed of sound.

Nose Cone Shapes

Rocket Body The rocket body creates drag in three places: width, surface, and base. A wider body creates more drag than a narrow one. As the width increases, air hits more of the surface area, creating drag. A smoother finish, or surface, creates less drag. A bluntly shaped base creates drag by making a "suction" area behind the rocket, which slows it down. Tapering the tail reduces this drag.

Rocket Body

Fins Fins, like any object attached to the outside of a rocket, create drag. Yet even though they create drag, rockets need fins to improve stability. Like the nose cone, fins should not have a leading front edge.  At subsonic speeds, fins work best if the leading edge is slightly rounded and the trailing edge is sharp. Fins on a rocket produce lift. The lift produced by the fins stabilizes and controls the rocket's flight.

Stability Fins on a rocket produce lift. The lift produced by the fins stabilizes and controls the rocket's flight.