University:
Washington State University
Course:
Physics 101 | General Physics
Academic year:

2019
Views:

85

Pages:

11
Author:

pravitate8aj14

Basic Rocket Aerodynamics Rocket Design Basic aerodynamic principles ● Thrust - upward force ○ For rockets: more thrust, more lift ○ Thrust is generated by the engine ● Drag - Resistance to motion through air ○ Cross-sectional area Up, Drag Up ○ Drag acts parallel to the direction of motion through air ● Lift - The main stabilizing force ○ Acts perpendicular to direction of motion through air Physics ● Center of Gravity-Average location of the rocket’s total weight - must be in front of CP ● Center of Pressure-the balance point of all aerodynamic forces on the rocket ● Center of Mass-The balance point of all mass in the rocket Cone ● “Breaks” the air around the body ● Pointed, round, spike ● Needs to meet flush with the body to prevent turbulence ● High weight moves center of gravity forward ● Optimal shape depends on speed Cone part 2 a needle also be used to create an artificial cone at high speeds Body ● General rule of thumb ○ 10-20:1 length to diameter ratio (aspect ratio) ○ Smaller diameter=less drag ● Round, polygonal ● Smoothe - prevent turbulence Helicopter rocket? Does it have to be round? Fins ● Too small and rocket will be unstable ● Too large and rocket will track into the wind due to “weather cocking” ● Many different shapes ● Control Surfaces ● Location increases drag at rear to keep direction - Shifts center of pressure rear fins part 2 A good size to start at is, 2D by 2D by D where D is the Diameter of the rocket body. Also fins may not be needed if the rocket exhaust can be redirected to stabilize