Proposal to Analyze and Re-Design Wentworth Wobbler Air Engine


Oct 27, 2013 (5 years and 2 months ago)



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Proposal to Analyze and Re
Design Wentworth Wobbler Air Engine

Submitted To:

Professor Richard L. Roberts

February 7, 2011


Christoper Guliherme

Gregory Leonardi

Stewart Wing

Eric Sullivan


Mech 578


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Wentworth Institute of Technology is moving to keep up with the times, and in doing so is
replacing the lathes and milling machines in the manufacturing lab

with computer numeric control (CNC)

machines. With these new machines, much of the freshmen syllabi

will change, especially the creation of
an air engine, or wobbler, which was originally done by hand and assembled over a semester. The CNC
machines will take a semester long project and complete it in a few weeks, so a new design is necessary
for the wob
bler. We are proposing to redefine steps taken to complete the wobbler, while tweaking the
design to make it more efficient. By working out the kinks or failures of the former design, incoming
freshmen will be able to be on the brink of technology and util
ize the most efficient manufacturing

Problem Definition

Freshmen enrolled in the Mechanical Engineering Technology at the Wentworth Institute of
Technology have the option of taking an introduction to manufacturing processes course in either th
first or second semester, at the end of which an engine (also known as a wobbler) fueled off compressed
air is assembled. The current curriculum requires that students machine each part pertaining to the
assembly through a variety of manufacturing proc
esses, including casting, lathe turning, hand tapping,
and press fitting of aluminum pieces. However, beginning next y
ear, the lathes and mills in the

manufacturing lab will be obsolete and replaced by machines run by computer numeric control (CNC)
This in turn, would hugely affect the process by which the wobbler is

therefore a new design
is necessary. While this design is being created, an opportunity to work out minor kinks to the current
engine becomes apparent, such as galling of pieces a
nd gouging of the piston. With the new CNC process
an opportunity also arises to eliminate the possibility of human error in the machining of the parts.

Literature Review

The air engine that is to be designed is built around one concept: simplicity. The
manufacturing, and mechanical workings must all be extremely simple and logical in order to be used as a
viable learning tool. The need for minimalism in the design and limit on manufacturing methods is what
will pose the most difficulty in the fi
nal design.

Most engine designs of the present day are extremely complex and rely on both electronic and
mechanical systems to create an extremely efficient energy generation system. As well, most engines are
made out of combinations of many different ma
terials which increase cost and often require many
different types of manufacturing. The goal of this engine is to be made out of a minimal number of
materials and easy to manufacture.

The new engine design will almost completely be based off the origin
al Wentworth Wobbler
design. The biggest advantage to this design over other air engines is the simplicity of the cylinder intake
and exhaust. The cylinder on most engines is stationary, and through the workings of various valves and
gears, intake and ex
haust valves into the cylinder are opened and closed during the revolution of the
engine. The Wobblers design makes the cylinder a moving part which rocks back and forth to stationary
intake and exhaust ports with the revolution of the flywheel. This des
ign characteristic eliminates the

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need for extra moving parts which would complicate both the manufacturing and the mechanical

The Need

With technology on the rise, both within and beyond Wentworth’s campus borders
, comes a need
to keep up
ate with the times. Replacing the milling machines and the lathes in the manufacturing
laboratory is necessary as they are “yesterday’s trash”. Multiple professors have expressed the need to
solve problems in the current design of the wobbler, and with the

necessary redesign for CNC machines,
comes the ability to work out those problems without much disruption or hassle. An analy
sis of the
current engine design presents the opportunity to implement changes to make it more efficient

and long
Furthermore, the design plans for the engine must be easy to read and comprehend, as freshman
students with little mechanical experience will be the ones manufacturing the engine. O
pportunities to
strengthen team
working ability, time management, and the
exercise of independence also arise, thus
preparing students for real
life career situations.

The Objective

The final design of the Wobbler engine should be an overall more efficient and sound
tool. The use of CNC machines will help eliminate h
uman error in the manufacturing process

and create
precise cuts of the engine parts. This, will in turn, create less error in the final assembly of the engine.
The power of the engine will also be increased through the new design. Students building the
engine will
then both r
ecord, through testing, and calculate the power output of the engine.

he longevity of the engine will be increased by manufacturing the engine out of harder and more
durable materials. One main point of failure in the original Wo
bbler is the pistons tendency to gall the
cylinder since both parts were made of the same soft aluminum. This problem
can be fixed by using two
different metals that won

t deteriorate quickly.
However, the materials used must still be relatively
ive and easy to machine.

In order to make keep the Wobbler as a successful learning tool, the design must be easy to
understand and to re
create. The desire for simplicity in the design
is so the mechanical processes within
the engine will be easy to un
derstand. With few moving parts on the engine and clear assembly plans, the
engine should reach these goals. This means all freshmen students in the Mechanical Engineering
programs at Wentworth should be able to easily create their own air engine.

The f
inal Wobbler En
design will, ideally, be a


learning tool for the Wentworth staff to use with students.
Students will
be able to look at the plans, and within a few classes have all the necessary pieces for th
eir air engine

Work Plan

The work plan for this project is straight forward and simple. First the original design of the air
engine must be analyzed for
any flaws or process improvements. These can include material analysis,
component interface issues, simple hardware se
lection, machining methods, and etc. Once the analysis is
complete, methods of improvement and solutions will be discussed and a clear direction will be set in
order to move the project along. Models will be edited and CNC code will be written once all pro
are solved completely. With the CNC code in hand, some manufacturing can begin. Fixtures will be

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designed and cut along the way to make sure all components are manufactured accurately. Once all
fixtures and manufacturing is complete, A prototype can
be assembled and tested. The group will analyze
the prototype and decided if there is more room for improvement with the design and manufacturing
process. The group will make all necessary changes and complete the project after all work is finished.

Task Name

Durati on



4 days

Thu 1/27/11

Formal Proposal

4.25 days

Wed 2/2/11

Model Original Drawings

5 days

Tue 2/8/11

Modify Models to Fit Our

5 days

Tue 2/15/11

Use Excel to Determine
the correct sizing for parts

6 days


Create CNC Codes

6 days

Tue 2/22/11

Create Drawings for New

6 days

Tue 2/22/11

Determine Stock Materials

3 days

Fri 2/25/11

make fixtures for
machining first prototype

3 days

Tue 2/22/11

Machine 1 Prototype of

6 days


Refine Design to make
machining easier

8.5 days

Thu 3/10/11

The Qualifications

This project will require knowledge in design, design analysis, CNC programming,
manufacturing processes, material science, and electronics. All together the group has

experience in all
these areas and will be able to accomplish the goals set for this project. Two of the group members have
taken a CNC programing class at Wentworth and all have taken a manufacturing processes course at
Wentworth. One group member is curr
ently working with a contacted manufacturing company that uses
CNC programming and manufacturing process on a daily basis. All members have taken courses in
design methods, design analysis, material science, and electronics. With each member bringing somet
unique to the group this project will be completed in a timely and efficient manner. All members of the
group have done projects on their own time that show the dedication to learning outside the classroom.
This group is well qualified to complete t

given tasks of this project.


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13 Summer Street ~ Topsfield,



~ 978


Wentworth Institute of Technology, Boston, MA

Bachelor of Science in
Mechanical Engineering Technology

August 2011

GPA 3.22/4.0

Dean’s List Spring 2008, Spri
ng 2009


Strength of Materials


Electricity and Electronics


Mechanical CAD Apps

Mechanical Design I

College Physics II

Differential Equations

Machine Design



Hand Sketching, Detail Drawings, Assembl
y Drawings, Solid Modeling


Strength Testing, Gauge Reading, Lathe, Milling, Thermocouple, Micrometer


Microsoft Word, Microsoft Excel, Microsoft PowerPoint, SolidWorks 2008, AutoCAD, Working


VAV International,
Woburn, MA

January 2010

December 2010

Spring Intern

Analyzed new Plumbing and HVAC systems to calculate purchasing orders of equipment.

Evaluated existing conditions of HVAC, Plumbing and Fire Protection to create accurate layouts

for retrofit

Edited drawing markups to create professional, precise drawings for customers.

On site evaluation of customer premise to establish baseline capacity for existing HVAC and Plumbing


Sandy Point Sailing Associa

Beverly, MA June 2004

August 2009

Summer Head Instructor

Supervised and coordinated a staff of six instructors by creating schedules and communicating expectations to ensure a
successful program

mmunicated with necessary parties including parents, vendors, employees to resolve conflicts

Reviewed and prioritized maintenance schedules and performance of boats to ensure safety on the water as well as
longevity of the boats


le Scout

Coordinated volunteer group

at Topsfield Town Library


implement an improved storage

system following Sping

Organized patrol of eight scouts and assigned tasks to help built teamwork
skills and instill sense of responsibility

Created monthly schedule of events for patrol to work on basic skills and prepare young scouts to become leaders
within the troop


America Reads

Work with young children on language skills and reading

to reinforce fundamentals of English

Provide positive model for kids to look up to and emphasize the importance of lower and higher level education


Interested in working in green engineering and alternative energy sources such as wind and sol
ar energy.

Also enjoy Sailing, Snowboarding, Hiking, Camping


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550 Huntington Avenue

Boston, MA 02115

(603) 553


Wentworth Institute of Technology
, Boston, MA

Bachelor of Science Mechanical Engineering Technology Exp: Aug. 2

GPA: 3.20/4.0


Material Science

Strengths of Materials

Machine Design


l Design II

Aided Manufacturing


Fluid Dynamics

Computer Programming

Differential Equations

College Physics II


Technical Competencies


AutoCAD 2008, Benchmen, SolidWorks 2010,

CamWorks 2010, Partmaker, Microsoft Office

: Mill
turn, Lathe, 4 and 5 axis Milling Machine, Metal Working, Solid Modeling, Basic CNC

Work Experience

Seabrook International
Seabrook, NH

Jan. 2010


Manufacturing/Mechanical Co

Created manufacturing drawings and models to assist the engineering team

Compiled process plans and pricing to help the sales team quote future jobs

Programmed, setup, and ran mill
turn and 3
5 axis milling equipment

Cambridge, MA

May 2009

Aug. 2009

Mechanical Intern

Assembled and maintained detection and automation systems to impr
ove performance

Communicated with 3
6 engineers to complete a large upgrade to the detection system

Compiled purchase orders by speaking with project engineers about what was needed

Home Depot
, N. Hampton, NH

May 2008

Aug. 2008

Lumber Associate

Acted as an integral member of team of 5
6 associates to receive, cut, and stock wood products

Enhanced customer service skills by helping custome
rs find the right supplies

Advised customers on product specifications to insure that the product met their needs

Craft Design
, Hooksett, NH

Mar. 2007

Aug. 2007

Computer Drafter

Prepared HVAC and fire protection plans for clients using AutoCAD

Generated existing condition plans to aid with the design of new mechanical systems

Gathered information from clients to better my understanding of what was wanted

Project Work

Remote Con
trol Rock Crawler
, Derry, NH

May 2007

Aug. 2007

Modified and constructed an electrical powered 1/10th scale vehicle, driven by remote control,

to climb over rough and rocky terrain that most remote control vehicles could not travel over.

pleted as an independent project

Air Engine
, Boston, MA

Sep. 2006

Dec. 2006

Manufactured and assembled an

engine that ran on compressed air and was constructed

mostly of aluminum parts fabricated with the use of the lathe, milling machine, and alu

casting process. Completed for Manufacturing Processes I

Leadership Experience

Resident Assistant/Senior
Resident Assistant

Aug. 2007


Coached youth football, youth lacrosse, and youth basketball




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33 High Street


Chelmsford, MA 01824


Wentworth Institute of Technology

Boston, MA

Bachelor of Science, Mechanical Engineering Technology

August 2011

GPA: 3.885/4.000

Dean’s list: Fal
l 2008
Spring 2009


Computer Aided Manufacturing

Fluid Mechanics

Manufacturing Processes I

Mechanical CAD Applications I

Material Science

Thermodynamics I

Strength of Materials


Differential Equations

Mechanical Design I


Electricity and Electronics



Strength Testing, Welding, Casting, Machining


Lathe, Milling Machine, Drill Press, Proto Trak CNC


Solidworks, CAMworks, AutoCAD, Autodesk Inventor, Compress,
Microsoft (Word, Excel, PowerPoint, Project)


Artisan Industries Inc.

Waltham, MA

Mechanical Engineering Co

January 2010
May 2010

Drafting and drawing of components used in Rototherms, Jet Vacuums, and Rotary

Draft and design two shipping frames for a hydraulic unit and a grinder

Edit specification sheets to be sent to customers to obtain information about specific jobs

Research components to be used in the frames for clearance and ease of use in the fie

Order parts and supplies from suppliers using Vantage

Assist in calculations of some ASME Code parts

Participate in discussions concerning the design and use of the hydraulic unit and grinder

Redesign drawing templates in Autodesk Inventor to improve


General Woodworking

Lowell, MA

Assembly Supervisor

January 2006


Organize and maintain the assembly area to ensure materials are available for production

Maintain a steady work flow by helping in the ass
embly process when needed

Monitor the inventory in the stock room to ensure that hardware is available

Meet scheduled deadlines by closely monitoring the progress of projects

Troubleshoot problems that arise in the assembly process

Resolve and mediate any
conflict within the assembly area

Train new employees on company policies and procedures to improve productivity

Great Brook Farm

Carlisle, MA

Assistant Herdsman

Aug, 2001

Assisted herdsman in the care of farm and animals and
provided care for cranberry bogs

Supervised up to six other workers


U.S. Masters Swimming


Volunteer at Lowell Catholic Carnival

Society of Manufacturing Engineers

Eric S.


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The Budget

One of

the goals for this project is to be able to manufacture the wobbler air engine here at
Wentworth. It also needs to be as simple as possible so incoming freshmen can spend minimum time
building it and more time analyzing. Our budget in turn is very simple
and straight forward. Wentworth is
providing all necessary equipment and utilities. Also there will not be any outside services because that
would add to the cost and complicity of the project. There is money on reserve to cover any unsuspecting
costs and
money for miscellaneous items.

The Projects Future

The redesign of the Wobbler
Air Engine is the number one priority for Wentworth within this
project. However, professors at Wentworth have also expressed a desire to create a dynamometer that
will hook up to the engine to measure its power. The dynamometer would be a simple design
of just a
coil that will light a light bulb when
hooked up, and possibly give a digital readout of torque. It will be
powered by attaching a belt to the flywheel of the air engine. Although this goal was originally set to be
part of the original project,

it is more likely that the dynamometer will not be created until a later time.

This project will be used as the basis of the new
Engineering programs
manufacturing course. T
he engine can be built in a short period time, and then thoroughly a
nalyzed by
the students. This is important since the Engineering program is more analytically based, and
concentrates less on manufacturing.


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The Air Car
. 1/28/2011.

How Stuff Works
. How The Air Car Works. 2/2/2011.

Mike Smyth’s Compressed
Air Engines
. 2/2/2010.