Welcome to Sophomore Engineering Clinic I

Instructor Introduction Personal Data Surveys Sent by email Fill out ASAP

Before we get started…

Sophomore Engineering Clinic

•Technical Communication• Most products are not built by engineers.• Engineers produce prototypes, product

designs and process designs, lab reports and design reports

•Engineering Design• Design is open ended, and problems are

often ill-posed.

Bottle Rocket (4 Weeks) Research Project/Prof. Development (4

Weeks) Some overlap with Bottle Rocket Project

Final Project (6 Weeks)

Schedule

Bottle Rocket Design

Design and fabricate a rocket out of a soda bottle.

Materials: 2 L soda bottle Foam Board Clay Duct Tape Water

Rocket will be pressurized to 40 PSI

Bottle Rocket Design

Goal- Design a rocket that will fly the farthest. Only “perpendicular” distance counts.

Using Parametric Design

Parametric Design: Using parameters to define a large number of instances, and then selecting the best one.

Examples:

Developing Parametric Models

Start with a rectangle Identify a family of shapes by defining one

parameter

2

3

Parametric Model – Case I

A family with 1 parameter

2

Width

Parameter = WidthHeight = 2 (constrained)

Parametric Model – Case I

A family with 1 parameter Defined an infinite number of design instances

2

Width

Parametric Model – Case II

Identify the family of shapes for a constrained width

2

3

Parametric Model – Case II

A family with 1 parameter. Defined an infinite number of design instances.

Height

3

Parameter = HeightWidth = 3 (constrained)

Parametric Model – Case III

X- and Y-Coordinates of 3 nodes are parameters Identify the family of shapes with one node

constrained

2

3

Parametric Model – Case III

Shapes are not constrained to rectangles

An Example Parametric Model for a Fin Family

Right triangles with height to length ratio of 2:1 Size and shape of fins are defined by either height or length

For Next Week

Develop a parametric model for a rocket with 3 parameters: Amount of water in rocket, Mass of clay used, 1 parameter to describe a family of fins.

Constraints

Clay is placed only in front of rocket, in a rounded shape.

Exactly 3 wings, placed 120o apart. Duct tape is used only to secure wings and clay to

bottle. Fin size and shape belong to a family that is defined

by a single parameter. (you define the appropriate parametric model for the wings)

Example test results

Holding 2 parameters constant while varying the third allows a systematic study of behavior to be recorded.

Take notes. The optimal value of one parameter might depend on the

values of the other two parameters. Observations should influence design.

Water (liters)

Dis

tanc

e (f

t)

Note:

Your grade for an upcoming report will be based on the technical description of the parametric model you develop

The grade of this report for this project will not be based on your final distance.

Assignment

Requirements for Next Week: Have your section leader ok your parametric model. Perform experiments to determine the set of

parameters that maximizes the distance. Communicate intelligently about parametric design The parametric model for the rocket cannot be

changed after a few tests. Choose a family of fins!

Find your Team and Instructor Introduce yourselves What is your unique fact?

Video and/or Design Questions of the Day What are you going to do to help your team succeed? What is Design? Any questions about project?

After Testing – Find your Instructor Discuss observations from the first test day

Before we start launching…