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Zane Middle School multiple rocket launcher

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Zane Middle School's multiple paper rocket launcher.

Abstract[edit]

The purpose of this project is to create a system to launch multiple paper rockets at once using air pressure. Zane Middle School teacher, Mr. Pinkerton was previously using a commercial Ultra Stomp Rocket bladder to fire off paper rockets one at a time. Triple B built and designed a system that fires at least six rockets at varying degrees of inclination. Triple B built undertook this project because of Engeneering 215 Intro to Design, a course at Humboldt State University instructed by Lonny Grafman.

Problem statement and criteria[edit]

Mr. Pinkerton, a science teacher at Zane Middle School, has used a simple “stomp-launcher” to propel single paper rockets in his past classes. While the “stomp-launcher” has proved to be easy to use, it has presented a problem with consistency and durability. When the students stomp on the bladder, each student applies a different force, so the velocity of the rocket is significantly different from student to student. Eventually the bladder wears out due to students stomping on it. Our project sets out to create a more consistent and durable system that propels multiple paper rockets at one time. Below is the criteria we are holding our project to.

Criteria
Weight
Definition
Consistency 6 10 9 Repeats the same results when propelled at the same conditions.
Safety 0 10 8 Does not cause any bodily harm to users or observers of the system.
Durability 4 8 7 Components maintain structural integrity throughout the products lifespan.
Effectiveness 2 8 6 Minimal amount of work in produces the desired amount of work out.
Compactibility 5 7 5 Ability to be taken apart and stored.
Ease of Use 3 7 4 Middle school students are able to comprehend and use the product.
Reparablity 1 6 3 Price of individual components and ease of replacing those components.
Adjustability 9 5 2 Ability to manipulate launch conditions.
Attractiveness 7 4 1 Appeal to middle school students.
Aesthetics 8 3 0 Product looks professional.

Description of final project[edit]

The Main Chamber rocket launcher design, illustrated in the table below, is made out of two different sized PVC tubing, six solenoid valves, a Schrader valve, wood stand, buckle straps, and a bicycle pump. Nine sections of one and a half inch diameter PVC tubing cut to four inches long are combined with six tee reducer joints and two ninety degree elbows to form the bent pressure chamber that the design gets its name from. All of the PVC pieces are glued into place. Additionally there are six sections of half inch diameter PVC tubing cut to three inches placed in the top part of the tee reducer joints. The six solenoid valves are then attached to the half inch PVC with an adapter. Screwed onto the end of the each of the valves is a section of half inch diameter PVC tubing cut to one foot with an adapter glued onto the end. The two ends of the bent pressure chamber are sealed with one coupling with female plug that adapts to a Schrader valve and another that adapts to a one-hundred P.S.I. pressure gauge. The pressure chamber is pressurized with the bicycle pump to the desired P.S.I. and then the button is pushed to open all of the valves releasing the pressure and launching the rockets. Finally, this entire system is angled and supported by a wood frame that is attached to the top of the pressure chamber. This wood frame adjusts the launch angle by placing a adjustable piece of the frame to the desired angle.

Picture Description
Three sections of PVC joined by three T-joints.
PVC
Polyvinyl Chloride is a hard plastic material mainly used in residential plumbing. The specific tubing we are using has been rated for 480 P.S.I. before failing. PVC parts are not only numerous and diverse, but they are also easily connected. PVC glue is comparable to concrete once it hardens and it is nearly impossible to separate two pieces of PVC that are glued together. Additionally, PVC is generally very inexpensive because it is a plastic and is mass produced. Since PVC is designed to transport fluids it can be made air-tight fairly easily.
A half inch solenoid valve.
Solenoid Valve
The pressure release valve implemented is electromechanically operated at the push of a button. The two-way valve is controlled by an electric current that runs through a coil opening the valve. Once the valve opens the air is released from the chamber and flows through the outlet. This valve was implemented because it has a fast release and a high reliability rate. Each valve requires about 320 mA to run at twelve volts, requiring about 3.84 watts to run at the recommended settings.
A wooden stand supporting the multiple rocket launcher.
Frame
The frame is made out of shelving brackets, aluminum tubing, and door hinges. The shelving brackets were cut into about two and a quarter feet long sections. The door hinges were then welded onto the bracket. The aluminum tubing was cut down into sections of eight and three-quarters inches in length and were subsequently welded to another set of hinges. Hook and loop pads were stuck onto all of the hinges and their corresponding place on the main chamber. This allows the frame to be attached and detached at will. The frame can support the chamber at multiple different firing conditions. Special angles like 30°, 45°, and 60°
A collection of wires coming off of a lantern battery.
Wiring
The valves are all wired in parallel powered by one twelve volt battery. In a parallel circuit all of the voltage is constant so all of the valves will open at the same time and speed. All of the wiring is hooked up with alligator clips for easy set-up, take-down, and maintenance. The circuit will probably only have a net wire loss of less than 0.3 volts across the entire system.
A twelve volt lantern battery.
Power
The twelve volt battery system is made of cells of ten AA NiMH rechargeable batteries. One cell is capable of providing 2000 mA. One cell can provide 24 watts. The valves require a total of about 23.04 watts. The power supply takes less than four hours to charge with the commercial charger.
A key fob, like that for a car but instead of unlock and lock there is on and off.
Trigger
The button is a 100mm wide big red push button. The button triggers the system wirelessly via an RF transmitter. The button has a separate battery compartment and takes two AAA size batteries. When the button is pushed the valves are opened, but all other times the valves are closed. The button is in a PVC case for structural and aesthetic improvement.

Costs[edit]

The cost for the items purchased that were used for testing and implementation. They are placed as name of items, prices, quantity, and subtotal. Additionally, it is totaled at the bottom and displays the price of the project costs.

Item
Price
Quantity
Subtotal
1/2" PVC End Cap 33 $2.93 11 1 1 $2.93 1
1 foot Sch 40. 1-1/2" PVC Pipe 35 $0.99 6 3 27 $2.97 4
1 foot Sch 40. 2" PVC Pipe 34 $1.15 7 3 28 $3.45 6
1/2" Threaded to Non-threaded adapter 32 $0.69 4 12 34 $8.28 23
12 Gauge Wire per foot 31 $0.59 3 20 35 $11.80 28
12 Volt Lantern Battery 30 $13.99 32 1 2 $13.99 30
12 Volt Universal Remote Kit 29 $17.98 33 1 3 $17.98 31
14 Gauge Wire per foot 28 $0.49 1 10 33 $4.90 11
6 Amp Fuse 27 $4.99 17 1 4 $4.99 12
9 Volt Battery Clip 26 $4.99 18 1 5 $4.99 13
Alligator Clips 25 $2.99 12 1 6 $2.99 5
Bike Pump 24 $26.99 35 1 7 $26.9 34
Double A Battery Holder 23 $5.79 19 1 8 $5.79 14
Electric Tape 22 $3.59 14 2 25 $7.18 19
Gravitech Push Button 21 $6.00 21 1 9 $6.00 16
Holding Frame 20 $10.96 29 1 10 $10.96 26
In-line Fuse Holder 19 $3.59 15 1 11 $3.59 7
Long Nose Pliers 18 $11.69 30 1 12 $11.69 27
Painters Abrasive 17 $1.34 8 1 13 $1.34 3
Piece to Holding Frame 16 $8.68 27 1 14 $8.68 24
Plugs for T-Shaped Adapter 15 $0.79 5 6 30 $4.74 10
Pressure Gauge (100 PSI) 14 $12.99 31 1 15 $12.99 29
Presta Valve (2-Pack) 13 $19.99 34 1 16 $19.99 32
PVC Elbow Connectors 1-1/2" 12 $1.99 9 2 26 $3.98 8
PVC Glue 11 $8.99 28 1 17 $8.99 25
PVC Primer 10 $7.99 25 1 18 $7.99 21
Schraeder Valve 9 $6.99 22 1 19 $6.99 18
Schraeder Valve Adapter 8 $0.50 2 1 20 $0.50 2
Screw-on Wire Connectors 7 $7.19 24 1 21 $7.19 20
Solenoid 1/2" Pressure Release Valve 6 $6.99 23 6 31 $41.94 35
Switch Rocker 5 $7.99 26 1 22 $7.99 22
Teflon Tape 4 $5.99 20 1 23 $5.99 15
T-shaped PVC Adapter 1/2" 3 $3.49 13 6 32 $20.94 33
Velcro Pads 2 $3.99 16 1 24 $3.99 9
Yellow Wire Connector Pack 1 $2.29 10 3 29 $6.87 17
Total: $322.57

Testing Results[edit]

The system successfully launched all six paper rockets at every launch angle. However, the stand was getting a bit shaky anytime we tried to fire at higher pressure than 100 p.s.i. For that reason we are suggesting that no one operate the system past 100 p.s.i. Also, all of the rockets went less than 10 feet below 10 p.s.i. therefore it is rather pointless to use the device at anything less than 10 p.s.i.

How to build[edit]

Materials:
All of the necessary pieces laid out.
In order to build the rocket launching system, one needs to have all of the following.

• 3' of 1½" P.V.C. cut into 9 sections that are each 4" long
• 6 1½" to ½" P.V.C. Reducer T-Joints
• 2 1½" 90° P.V.C. Elbow Joints
• 2 1½" P.V.C. Connectors
• 2 1½" to threaded ½" P.V.C. Reducer
• 6 ½" P.V.C. Sections cut to 2"
• 6 ½" P.V.C. Sections cut to 1'
• 6 ½" Electric Valves (solenoid valves work best for this)
• 12 ½" Threaded to non-Threaded P.V.C. Connectors
• 1 ½" Pressure Gauge (perferably one that goes to at least 100 p.s.i.)
• 1 ½" Schraeder Valve
• P.V.C. Glue (not pictured)
• Teflon Tape (not pictured)

Step 1:
Four four inch section of one and a half inch P.V.C. connected by three one and a half inch to half inch P.V.C. Reducer T-joints.
Take one of the 4' sections of 1½" P.V.C. and put one end inside one end of the 1½" to ½" P.V.C. Reducer T-Joints. do this until you have two separate pieces that look like that picture. Do not glue the pieces yet.
Step 2:
Four four inch section of one and a half inch P.V.C. connected by three one and a half inch to half inch P.V.C. Reducer T-joints with a one and a half inch ninety degree P.V.C. elbow on the left end.
Attach one of the 1½" 90° P.V.C. elbows to one end of each of the sections. Do not glue the pieces yet.
Step 3:
The main pressure chamber of the multiple rocket launcher without the launching tubes or end pieces.
Connect the two mirror sections you have made with the final 4" section of 1½" P.V.C. Connect this 4" section to one of the 1½" 90° P.V.C. elbows and then the other creating a "U" shape. Check what you have against the picture if it looks the same then move on.
Step 4:
The main pressure chamber of the multiple rocket launcher without the launching tubes or end pieces.
Take each part off and glue every connection with P.V.C. glue.
Step 5:
The main pressure chamber of the multiple rocket launcher without the launching tubes, pressure gauge, or Schraeder valve.
Now, glue the 1½" P.V.C. connectors to each end of the main chamber. Then glue the 1½" to threaded ½" P.V.C. reducers into each connector.
Step 6:
The main pressure chamber of the multiple rocket launcher without the valves, pressure gauge, or Schraeder valve.
Glue on each of the 6 2" long sections of ½" P.V.C. into each of the 1½" to ½" P.V.C. reducer T-Joints. Then, glue the ½" threaded to non-threaded P.V.C. connector with the non-threaded side down, onto the 2" sections of ½" P.V.C.
Step 7:
A foot long section of half inch P.V.C. with a threaded to non-threaded connector on one end.
Glue the other six threaded to non-threaded ½" connectors onto the ends of the six 1' long sections of ½" P.V.C. Wait until all of the P.V.C. glue has dried before moving on to step 8.
Step 8:
The multiple rocket launcher.
Wrap the threads of the valves, the pressure gauge and the Schraeder valve with Teflon tape. Once the threads are wrapped screw the valves into the ½" threaded to non-threaded connector. Be sure the valve is facing the right way and that valve does not get cross threaded. Once the valve is on the main chamber piece, screw the 1' ½" P.V.C. sections onto the valves. Next screw the pressure gauge into one of the ends of the "U" and screw the Schraeder valve into the other one.

Discussion[edit]

The multiple rocket launcher kit was made to interact with children at Zane Middle School for educational value and safety. During testing, the paper rockets design is crucial to achieve maximum amount of distance per launch. The design was made with low cost valves and PVC to maintain low cost maintenance. One of the criteria that was not met to the desired degree was consistency. This is due to the design requiring a steady amount of ampere to set of all the valves. Without a battery to deliver the amount ampere needed, the rockets will not launch consistency and simultaneously. Also, the higher the pressure, the higher amount of ampere required to trigger the valves. If the pressure is kept below 50 psi, the rocket will launch more effectively.