Drag - Drag -

1.1. Friction due to fluid ( gases or Friction due to fluid ( gases or liquids)liquids)

2.2. Poor taping creates turbulence Poor taping creates turbulence on rocket surface.on rocket surface.

Aerodynamics –Aerodynamics –1. Study of the forces acting on 1. Study of the forces acting on

objects in motion in fluids.objects in motion in fluids.

Streamline –Streamline – 1. An object shaped to make air 1. An object shaped to make air flow smoothly around itflow smoothly around it

Inertia –1. An object wants to keep doing what it is already doing unless a force acts on it. ( Due to mass)

2. The rocket needs mass to help it continue to travel upward.

Inertia is the tendency of an object to resist any change in motion. It is associated with the mass of an object.

Inertia

A bottle rocket that isHEAVIER has MOREInertia, because it hasMORE mass. MORE Inertia will offerGREATER resistance to a change in direction.Therefore the wind willhave LESS effect on abottle with MORE INERTIA.

A LIGHTER bottle rockethas LESS inertia, because it has LESS mass. LESS inertia means the rocket will have LESS resistance to change in direction. Consequently, the wind has a GREATER effect on the rocket’s path of motion.

Correct amount of Mass

Incorrect amount of Mass

BALLAST: any mass added to a vehicle to improve STABILITY and increase INERTIA.

WindDirection

Air Resistance(DRAG)Ballast

Center of Mass

Stability: Ballast towards the nose cone will shift the center of mass forward.

Inertia: More weight (ballast) increases inertia and will prevent a bottle’s path of motion (or Trajectory) from being prematurely overcome by DRAG & WIND FORCES........CAREFUL! Too much Ballast will make the vehicle too heavy ( Newton’s 3rd Law).

Center of Mass / Gravity –Center of Mass / Gravity –

1. The exact point where the mass 1. The exact point where the mass is balanced on the rocket.is balanced on the rocket.

2. A higher center of mass enables 2. A higher center of mass enables the rocket to have inertia to fly the rocket to have inertia to fly straight and upward in altitude.straight and upward in altitude.

Fin Specifics – Fin Specifics –

1.1. 3-4 Fins evenly balanced for 3-4 Fins evenly balanced for stabilitystability

2.2. Fins should be small and light Fins should be small and light but still firmly attachedbut still firmly attached..

** increase surface area with fins ** increase surface area with fins help create stability.help create stability.

Rocket Fin ShapesRocket Fin Shapes More Aerodynamic fins:Thinner, more streamlined fins reduce drag. Position fins toward the tail of the rocket (moves CP!).

Nosecone Guidelines – Nosecone Guidelines –

1.1. Nose is lengthened for higher Nose is lengthened for higher center of mass.center of mass.

2.2. Nose is filled with paper for Nose is filled with paper for stability and evenness of mass.stability and evenness of mass.

3.3. Nose is a parabola shaped for Nose is a parabola shaped for reduced drag and aerodynamicsreduced drag and aerodynamics

Maximum Mass -Maximum Mass -

The mass of your rocket should not exceed 250 grams. Optimum mass is approximately 200 grams

Center of Lateral Area (CLA)Center of Lateral Area (CLA) - -

1. The point along the rocket where 1. The point along the rocket where the wind forces on either side are the wind forces on either side are equal.equal.