Defining a problem- The Problem is we need this rocket to fly a Maxim height, while keeping costs low and flight time high.
mass = density x volume
weight = mass x gravity
volume = thickness x width x length
mass = density x volume
momentumwater = masswater x velocitywater
Newton's Third Law of Motion
For every action, there is an equal and opposite reaction.
momentum of the rocket is equal to the momentum of the water
the density of water is about 800 times the density of air
increasing the velocity of the ejected water, or by decreasing the mass of the rocket
The air density for your bottle rocket is constant at 1.2 kg/m3.
Drag = .5 x air density x velocity2 x frontal area x coefficient of drag
design decisions that result in lower drag coefficients will reduce drag
long nose and a drag coefficient of 0.299
Frontal Area = π x radius2
To move the center of gravity towards the nose of the rocket, mass should be added to the nose.
The distance between the center of gravity and center of pressure is known as the static margin
the static margin should be greater than or equal to the bottle diameter
change the location of the center of pressure is by adding more material to the nose or tail of the rocket.
Roll is a twisting motions about the roll (longitudinal) axis. Roll movement is not really a problem on a water rocket since it does not tend to alter the rocket's flight path.
Pitch refers to an up and down movement of the rocket's nose. This movement can take the rocket off of its intended flight path and could result from a gust of wind. Careful attention to the location of the center of gravity and center of pressure will ensure pitch stability.
Yaw refers to the side to side movement of the rocket's nose. This movement can take the rocket off of its intended flight path and could result from a gust of wind (very similar to pitch). Careful attention to the location of the center of gravity and center of pressure will ensure yaw stability.
gravity is relatively constant at 9.8 m/s2
mass increases by 1 unit, weight will increase by 9.8 units
A newton is the metric unit for force. One newton is the force required to accelerate a mass of one kilogram to one meter per second squared.
Density is a material property, so you control density by the materials you choose.
Volume depends on the size and shape of the rocket components you design and select.
convert the mass in grams to kilograms -mass = 4.096 g x 0.001
mass = 0.004096 kg
The first (leftmost) design has a relatively short nose and its drag coefficient is 0.533.
The second image has a longer nose and a drag coefficient of 0.364.
The last design has a long nose and a drag coefficient of 0.299.
Drag is directly proportional to the drag coefficient, so design decisions that result in lower drag coefficients will reduce drag.
Lawndart recovery- high positive Static margin
Tumble recovery- small static margin
backslider recovery- high, negative static margin
The parachute is an active recovery system.
The space inside of the nose cone tube may be too small. Look for items in the Recovery system work area called Deploy Volume and Tube Volume.
The three rockets chose before you are the three highest flyers of their time. They were designed to beat the current number one’s. Eckeress was designed to have a light chassis with a high static margin but failed when more efficient style of fins were made. Dread’s Curved wings were to lighten the rocket without sacrificing stability but ultimately sacrificed time and Boomer’s cleaver wings provide stability while having a low weight. I plan to take Boomer for field testing because of its time.
Eckeress Boomer Dread
Time 3 5 4
cost 4 5 5
weight 3 4 4
Stability 3 5 4
I'm going to put together boomer with the top of a bottle, foam board, and card stock. I will use masking tape for the cone and hot glue on the fins. The fins are evenly spaced out by 2.5 inches per fin. The bottle will have .7 litters of water and 70 pounds of presser. the nose cone will be 11.5 inches in length. The active falling system is a 11 by 11 square.
The prototype work launching its optimal height. The active fall system failed. Boomer crashed head first into the ground releasing its wings.
Fall release system moved farther foreword to allow proper release.
Bottle would not be reused, The fins would be pre-cut, 12,000 for rent, electricity, Manpower, Machine Power, supplies, water.