Catapult Project
By:
Avani Patel
Brian Prohaska
Nicole Worytko
Kyle Hughes
Table of Contents
Section
Page Number
Group Development
Roles and Responsibilities……………………………. Page 1
Team Constitution…………………………………….. Page 1
Timeline……………………………………………………… Page 2-3
Problem Statement…………………………………………… Page 4
Background/ Justification…………………………………… Page 4
Customer……………………………………………………... Page 4
Scope…………………………………………………………. Page 5
Deliverables………………………………………………….. Page 6
Brainstorming
Topics to Further Understand………………………….. Page 6
Things We Know……………………………………..... Page 6
Research and Generate Ideas
Information We Know Understand…………………….. Page 7
Bibliography……………………………………………. Page 8
Possible Ideas…………………………………………… Page 9
Identify Criteria and Constraints………………………………. Page 11
Explore Possibilities
Design Sketches Created By Each Team Member……… Page 12
Balance Sheets…………………………………………...
Nicole’s Sketch…………………………………… Page 13-14
Avani’s Sketch……………………………………. Page 15-16
Kyle’s Sketch…………………………………….. Page 17-19
Brian’s Sketch……………………………………. Page 20-22
Hybrid Sketch…………………………………….. Page 23
Best Potential Solutions………………………………… Page 24
Select an Approach
Design Matrix…………………………………………… Page 25-26
Process Took to Choice Solution………………………... Page 27
Develop a Design Proposal
Detail CAD Drawings……………………………………. Page 28
Bill of Materials………………………………………….. Page 29
Build Process…………………………………………….. Page 30-31
Test Plan…………………………………………………. Page 32
Prototype
Problem Chart…………………………………………… Page 33
Work Process Usefulness……………………………….. Page 33
What We Ended Up Changing………………………….. Page 34
Test and Monitor
Trials…………………………………………………….. Page 35-36
Plot………………………………………………………. Page 37
Patterns…………………………………………………… Page 37
Refine
Design Changes Made To Prototype……………………. Page 38
Why Our Chart Came In Handy………………………… Page 39
Lessons Learned………………………………………………… Page 40
Summary………………………………………………………… Page 41
Attachments (Pictures)…………………………………………. Page 42
Group Development:
Role Responsibilities
Leader- Brain Prohaska
 JOB: to keep everyone on task, and accomplish the assignment
PowerPoint Scribe- Nicole Wortyko
 JOB: finish the PowerPoint with the help of Avani
Technical Report Scribe- Avani Patel
 JOB: jot down notes, and finish the tech report with the help of Nicole
Time Keeper- Kyle Hughes
 JOB: to keep everyone on task, and update the timeline
Team Constitution
Article 1: Stay focused
Article 2: Respect others
Article 3: Be open to new ideas
Article 4: No suggestions are dumb
Article 5: Corporation is important
Article 6: Negotiate
Article 7: Be assertive, to put over your points without aggression
Article 8: Pay attention
Article 9: Don’t interrupt when other people are talking
Page 1
Timeline:
Plan Date
Act. Date
Start
Who’s
Responsible
Start
Comp
03/17/10
03/17/10
03/18/10
03/18/10
Team
03/17/10
03/18/10
03/18/10
03/19/10
03/19/10
03/29/10
03/29/10
03/17/10
03/18/10
03/18/10
03/19/10
03/19/10
03/29/10
03/29/10
03/19/10
03/19/10
03/19/10
03/19/10
03/23/10
03/29/10
03/31/10
03/19/10
03/19/10
03/19/10
03/19/10
03/23/10
03/29/10
03/31/10
Avani
Avani
Avani
Avani
Nicole
Nicole
Team
03/29/10
03/29/10
04/01/10
04/01/10
Team
03/30/10
03/31/10
04/02/10
04/04/10
Kyle
03/31/10
03/31/10
04/06/10
04/06/10
Avani
03/31/10
03/31/10
04/07/10
04/07/10
Avani
04/01/10
04/01/10
04/08/10
04/09/10
Avani
04/02/10
04/02/10
04/12/10
04/12/10
Avani
04/05/10
04/05/10
04/13/10
04/13/10
Team
04/05/10
04/05/10
04/14/10
04/14/10
Avani
04/06/10
04/14/10
04/12/10
04/19/10
Brian/ Kyle
Task
Comp
Page 2
Group Development
- Roles and Responsibilities
- Team constitution
Timeline
Problem Statement
Background/ Justification
Customers
Scope
Deliverables
Brainstorming
- Topics to Further
Understand
Brainstorming
- Things We Know
Research and Generate
Ideas
- Information we now
understand
-Bibliography
Research and Generate
Ideas
- Possible Ideas
- Sketches Made By Each
Member
Identify Criteria and
Constraints
Explore Possibilities
- Balance Sheets
Explore Possibilities
- Best Potential Solutions
Select an Approach
- Design Matrix
Select an Approach
- Process Took to Choose
Solution
Develop a Design Proposal
- Detail CAD Drawings
04/15/10
04/15/10
04/16/10
04/16/10
Brian
Develop a Design Proposal
- Bill of Materials
04/16/10
04/16/10
04/19/10
04/20/10
Brian/Kyle
Develop a Design Proposal
- Build Process
04/16/10
04/27/10
04/26/10
04/27/10
05/01/10
05/16/10
05/16/10
05/16/10
Team
Avani
Build the Catapult
Develop a Design Proposal
- Test Plan
04/28/10
04/28/10
05/16/10
05/16/10
Avani
Prototype
- Problem Chart
- Work Process Usefulness
-What We Ended Up
Changing
04/29/10
05/04/10
05/17/10
05/18/10
Kyle/ Brian
05/05/10
05/07/10
05/17/10
05/17/10
Team
Test and Monitor
- Trials
- Plot
- Patterns
Refine
- Design Changes Made To
Prototype
- Why Our Chart Came In
Handy
05/10/10
05/10/10
05/10/10
05/10/10
05/18/10
05/18/10
05/18/10
05/18/10
Team
Team and
Individuals
05/13/10
03/18/10
04/01/10
05/17/10
05/19/10
05/13/10
05/14/10
05/14/10
05/18/10
05/20/10
05/19/10
03/18/10
04/20/10
05/19/10
05/19/10
05/19/10
05/18/10
05/17/10
05/20/10
05/20/10
Avani
Avani and Nicole
Nicole and Avani
Team
Team
Page 3
Lessons Learned
Summary
Attachments (Pictures)
Technical Report
PowerPoint Presentation
Technical Report Review
PowerPoint Presentation
Review
Problem Statement:
Our group has been asked by the King to design and build a catapult during the Middle Ages.
According to the King, the design should be able to throw tennis balls, and be able to be operated
from at least four feet.
Background/ Justification:
Our device will be the best catapult in existence because it will be able to throw tennis balls, and
be able to be operated from at least four feet.
During the Middle Ages a military manufacturer in Europe has been asked by the King to design
a new catapult. The King wants this to be the best catapult in existence and should be able to
throw tennis balls.
Customers:


Mr. Pritchard- Integrated Technology Concepts class instructor
King
Page 4
Scope:
Our group is required to design and build a catapult using the 12 step PLTW design process. Our
team is made up of four students: Nicole Worytko, Brian Prohaska, Avani Patel and Kyle
Hughes. We are to hand in a typed final report, a PowerPoint, and a catapult. Our progress
throughout the entire project will be documented. On our timeline, we will also keep records of
the dates we completed each task.
We will be getting information from the following people:



•
Mr. Pritchard-Tech
Ms. Hernacki- Math and Dimensioning
Mr.Cotie- CAD Drawings
(Materials-Wood, metal screws, 2 bungee cords, screw with hook, and tennis balls, wood
rod, and metal rod.)
Guidelines and constraints for this project:
-Must be triggered from at least four feet away
-Must be able to throw the tennis ball at least 30 feet
-The frame of the catapult must be made out of wood
-The catapult must be able the trajectory angle at which it is throwing the ball from
-Can be hand-loaded and reset
-The only projectiles that can be used are tennis balls
-The frame of the catapult cannot exceed 24”x24” and it cannot be taller than 24”
-The entire catapult must be safe (Meaning: no rough edges, no exposed screws or nails, no
splintered wood)
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Deliverables:
By the end of the project we will produce:
 A technical report will be given to Mr. Pritchard for evaluation. This includes all
documentations of the project and will be put together in a binder
 The Power Point will be used for our presentation. This presentation will be given orally
for our 3rd period technology class.
 The catapult will be given to Mr. Pritchard along with the Tech report. It will be able to
launch a tennis balls according to customer requirements.
Brainstorming
Topics That Need To Be Further Understood:







Catapult designs
Catapult’s function
Catapult types
Catapult angles
Wood types
Base types
Type of Screws
Things we Know:
-
Catapults are made out of wood.
The catapult is used to launch items.
The way the catapult is made affects the distance and angle the item is thrown.
There are many different types of catapult designs.
We use different tools for this project like the vertical band saw.
Catapult arm needs to be positioned right in order for the tennis ball to be thrown.
Catapults were used as weapons in the medieval times.
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Research and Generate Ideas:
Information We Now Understand:
 Catapult Designs
Some possible catapult designs were Avani’s, Nicole’s, Brian’s, Kyle’s, and Hybrid designs.
Brian made an additional design on CAD that we could also use. The hybrid design seems to be
the best as it takes the good qualities from each of our drawings and creates one good catapult.
Also the hybrid catapult adds on other good ideas we thought of during brainstorming.
 Catapult’s Function
In the medieval ages, a catapult was a machine design to break walls and fortifications for an
attack. This machine would fling giant boulders at an enemy. We have been asked in this
scenario to build a catapult for a king that will launch a tennis ball 30 feet forward.
 Possible Catapult Types We Could Build
For the types of catapult, we could build a trebuchet or onager catapult. A trebuchet is a device
dealing with balances and counterbalances to pull an object through and up into the air. An
onager catapult has an arm with a wire or string that uses tension to generate power and fire the
arm, hurling the object into the air. We cannot build a ballista.
 Wood types We Could Build With
Some possible wood types we could build with are the following: whitewood, oak, pine, birch
and maple. Whitewood and oak have a lot of durability and strength, while pine is a softer wood,
with less strength. All these wood types have there own strengths and weaknesses, and are used
in different conditions.
 Base Types
One base type is a hollow square base, with four planks meeting at end to create a square.
Another is a full base, which is basically a square base with no gaps. The third type is a triangle
base where three pieces of wood connect to make a triangle. With hollow bases, it requires less
wood but gives a little less support. Full bases use a lot more wood, and provide more support.
 Types of screws
Some possible types of screw are threaded rods, regular screws, plow bolt or flat headed screw.
We could possibly counter bore the screw into the wood to prevent the screw from sticking out
of the wood. This means flat head or regular Phillips screws would be preferable to other screws.
Page 7
Bibliography:
 http://www.diadot.com/wood/
 http://www.sawdustmaking.com/Wood/wood.html
 http://www.lowes.com/pl_Dimensional+Lumber_4294816004_429493
7087_?cm_cr=Lumber-_-Web+Activity-_Lumber+A1+Activity+3.19.10-_-SC_Lumber_Area1-_-22613_3
 http://www.aseasontoturn.com/wood/wood_index.html
Page 8
Possible Ideas:
1. We could build a catapult or a trebuchet
2. The catapult could use a wire-draw back and then release that to fire
3. The catapult can have a long, arm, which has a spring connected to the frame to give it
extra strength
4. The catapult can have increased amounts of springs to help with any possible issues we
have with firing the tennis ball the required distance.
5. The catapult will be able to use a wider base, which means it can accommodate a larger
arm and winch for the wire
6. We can build the catapults out of most types wood; one possible solution is using white
ash wood.
7. If we do design a trebuchet we can have a larger counterweight to increase power
8. The trebuchet can use less pricy materials, instead of highly expensive things, such as
higher price wood like mahogany
9. To be able to fire the catapult from a distance we could use a release mechanism that can
be attached to a string we could pull
Page 9
Design Sketches Made By Each Member:
Page 10
Identify Criteria & Constraints:
For this project we have constraints that include:
1) The catapult must be designed so that it can be triggered from a distance of 4 feet.
2) The catapult must be able to throw a tennis ball at least 30 feet as measured by a line that
is perpendicular to the front of the catapult.
3)
4)
5)
6)
Accuracy is important so plot where each throw lands.
The catapult can be hand- loaded and reset.
The frame of the catapult is to be made of wood.
You must build into your catapult a method to measure the trajectory angle that is being
used to throw the tennis ball.
7) No other projectiles are to be thrown other than the tennis balls.
8) That catapult cannot be taller than 24”
9) The maximum floor space occupied by the catapult frame is 24 by 24 inches.
10) An elastic cord cannot be used to hurl the projectile unless it is secured that there is
zero probability that it will detach from whatever devices that are used to secure it.
11) User safety must be built into catapult, i.e., no splintered wood, no exposed screws or
nails, reliable release mechanism.
12) Keep a reference page.
13) Show all mathematical calculations used in designing the catapult
Page 11
Explore Possibilities:
Balance Sheets:
Page 12
Nicole’s Sketch
Pros+
+ Angle possibilities are drawn
+Dimensioned
+ Parts describe what they do
+ Bowl is dimensioned
Cons- Hard to follow
- Too many words
- Hard to build
+ Spring is drawn
+ Scale is drawn
Nic
ole’s Sketch contains many positive aspects that we could use. For example her sketches are
dimensioned, the spring is drawn, there is a scale, it has angle possibilities, and each part
describes what it does. Some negative aspects are that it is hard to follow, it had too many words,
and it may be hard to build. Overall this sketch is high our list of possibilities.
Page 13
Page 14
Avani’s Sketch
Pros+
+ Dimensioned
+ Spring is drawn
+ Drawn in pencil
+ Base is 24 x 24
+ Holes are dimensioned
+ Bowl is dimensioned
Cons- Parts are not drawn separately
- Over dimensioned
- Arm has no support
- No angle on arm
- Uses unnecessary amount of wood
- Hard to follow
+ Has a scale
Ava
ni’s
sketch contains many positive aspects that we could use. For example, her sketches are drawn
neatly which will allow us to add notes if needed. The base is
24 x 24, the spring is drawn, there is a scale, and the holes are dimensioned. Some negative
aspects that may affect the final design are that it is over dimensioned and the arm has no
support. Overall this option is kind of high on our list of possibilities.
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Page 16
Kyle’s Sketch(s)
Pros +
+ Stable
+ Parts shown separately
+ Drawn in pencil
+ Spring is drawn
+ Looks appealing
Cons- No straight lines
- Costly
- Sloppy
- String not efficient
- Only some parts dimensioned
- Bowl not dimensioned
- Hard to build
- Long arm
Kyl
e’s
sket
ch
cont
ains many positive aspects that we could use. For example, his parts are drawn separately, and
the spring is also drawn. Some negative aspects are that the sketch is not drawn straight, and it
looks hard to build. Also some parts are not dimensioned, and the string is not efficient. Overall
this sketch is average on our list of possibilities.
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Page 18
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Brian’s Sketch
Pros+
Cons-
+ Drawn in pencil
+ Describes what each part does
+ Spring is drawn
+ Holes are dimensioned
+ One part is drawn separately
- Sloppy
- Hard to follow
- No scale
- No straight lines
- Unnecessary toning
- Only some parts dimensioned
- Bowl not dimensioned
- No angle on arm
Bria
n’s
sket
ch
cont
ains
many positive aspects that we could use. For example, his sketches are drawn in pencil, the
spring is drawn, and the holes are dimensioned. Some negative aspects are that it is hard to
follow, there are no straight lines, unnecessary toning is added, there is no angle on the arm, and
only some parts are dimensioned. Overall this sketch is average on our list of possibilities.
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Page 21
Pros (+)
Cons (-)
Page 22
Hybrid Solution
+ Has good qualities from all drawings
+ Is strong durable design
+ Less wood used
+ Meets all criteria and constraints
+ Fully dimensioned
+ Easy to see each person’s input
+ Straight neat lines, no splotches on paper
- Took long time to think of design
- Took long time to get right
This is a sketch that has all positive aspects, expect is took a long time to think of, and get it
right. The best part is that it’s fully dimensioned, and contains all of the customer requirements.
For example it has a trajectory angle measurer, and it is durable. Overall this is a sketch is
definitely on are high list of choices.
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