 we tested 3 variable, seeing as how 2 liter bottles were most attainable we stuck with that, and tested for water volume air pressure and cross section.
i. we went with 40% volume or approx 800ml
ii. the higher the psi the higher the rocket, so we kept it at the 80 PSImax
iii. we only tesed the 2 liter bottles
iv. the cost function is added in the graphs
Tests/Optimization
The optimizations were done by finding out which variable provides the best cost score. Then after figuring out all of the parts, placing all of the variables together to form the final solution as posted above.
Steps
 Test the fill values with the constants 2 Liter bottle, 2.1 exhaust diameter, 80 psi.
 Test pressure with constants 2 Liter bottle, 2.1 exhaust diameter, .45 fill value.
 Test the bottles by utilizing similar constraints as the fill value test with constants 80 psi.
 The bottle test concludes with no bottle other than 2 Liter can reach greater than 20meter
 With the 2 Liter bottle chosen, test the exact exhaust and fill value for it with 2 Liter bottle and 80 psi constant.
 The optimization concludes that exhaust diameter .8.12 cm and fill value .25 .4 is good
Overall Constants 


5 degrees C 

.5 Drag Coefficient(changin it made negilible differences to cost) 

2L Bottle 



348 grams 


2000 mL 


0.0007853975 CSA 

1L Bottle 



333 grams 


1000mL 


0.00044178609375 CSA 

20oz Bottle 


322 grams 


591mL 


0.000371223037109375 CSA 
Analyzing/Optimizing:
To seek a perfect optimization for this project it would of took serval days and many many trails in the excel sheets. So due to short timing I seeked relative maximums for this project using the Simulator Speadsheet given to us. I started to optimize by first finding/settling with a base rocket bottle then start to change each variables little by little. I kept the size of the bottle rocket to X liters (its a secret) while I was analyzing for the exhaust diameter, fill ratio, and internal pressure maximums. After I settled the maximums for these variables I optimized the bottle size which influenced the volume size obviously. Well here are my graphs, i am still skeptical to show my excel sheet.
Rocket optimization
Steven Manfull, Nick McNeil, Kyle Offutt
We use the Peter Neilson excel spread sheet to optimize 4 different aspects of our water bottle rocket.
i. First, we optimized the water to air ratio inside the bottle. After plugging in different values from 0 to 1 we found that a ratio of .35 water is the ideal ratio. This ratio applied for both a 1L bottle and a 2L bottle.
ii. Next was the size of the nozzle to push water out of. This size we found to be .6cm diameter.
iii.Next was the size of bottle, we found that 1L would be better, mostly due to reduced weight and smaller cross sectional area.
iv.Lastly, our cost function determined that 30 PSI would be the ideal pressure to launch our rocket.This one seems the least likely to be accurate since it is intuitive that more pressure would result in a higher launch.
rocket cost function Kyle Offutt (1)
 In our rocket project we used the Peter Nielson Simulator to optimize our rocket.
The factors that were most effective were the Fill Ratio & Starting Air Pressure.
We originally started off with a 2 liter bottle, but decided to change to a 1 liter bottle due to the Cross Section Area
affecting the height. It turns out that our cross section area was actually calculated wrong, but we still are going to test a liter bottle…
Anyway, time is running short.. Until Next Time! Well hopefully there is a next time after the test launch today xD
Rocket cost Function
Graphs are in the above Link ^^^
Team Members:
Nathan Nixon
Rueben Ramirez
Michael Bond
2 Liter bottles will yield the desired height while adding little cost
We then graphed results for height, max acceleration, and cost (X axis scale is supposed to be .05.7) Optimization occurs at about .3
Pressure is maximized until the upper limit, so max pressure will be best
Through the optimization our estimated height is 50m and cost is 65
 Our rocket design was tested using the Peter Neilson simulator and the Rocket Cost Function.
 Optimized design for:
i. Water volumeThe max cost function value is reached by a .3 filling ratio.
ii. Air pressurefrom this graph we found that 30 PSI would yield the max cost function.
iii. Volume vs weight, i.e. using a 2L, 1L or 20 oz bottle > which is more effective?A 1L bottle seemed to give a higher cost function.
iv.Exhaust diameter the optimum diameter for the exhaust found was a .6 diameter.
v. Cost using the cost function given our cost was 224
Our results can be found graphically here rocket cost function Kyle Offutt
To find what type of bottle we wanted to use, we changed the values for volume and determined the maximum. (volume vs. height graph) We decided that a 2 liter bottle will work best.
We used the same procedure to maximize the exhaust diameter. (diameter vs height graph)The graph steadily goes up as the exhaust diameter increases, so we will use the plain bottle opening, to maximize the diameter.
We also looked at the filling ratio. The filling ratio graph peaks around .46. (filling ratio vs height graph) This means we will fill up 46% of the 2 liters volume with water which will be about 950 mL of water for the launch.
The maximum height also encreases steadily as the air pressure increases, so we will use the maximum amount of air pressure we can.
When we put theses values into the simulator, we got an expected max height of around 40 meters and an estimated cost score of about 76.
Excel graphs–> rocket analysis