Overview: Engineering design tools:

-Brainstorming √

-Engineer’s Logbook: Documentation √

-Estimation

-Prototyping

-Reverse Engineering

-Project Management

Estimation

“Back-of-the-envelope” calculation to test for design feasibility

Peak-Performance Design Competition example:

Need to estimate the power required from the battery

Theory	Calculation
-Max “Weight” of 2kg -Less Batteries Less Weight	-Hope for 0.9 kg -One 9-V Battery

Theory	Calculation
Gravitational Force Equals Mass Times Gravitational Constant	g=10 N/kg (N: Newtons)
F=mg	F=9 N

Theory	Calculation
Energy Equals Force Times Distance	Δy = 90cm х 0.01m/cm =0.9m
E=F Δy	E = 9N х 0.9m = 8 J (J: Joules)

Theory	Calculation
Mechanical Power Equals Energy per Unit Time	Pmech=8J/7s=1.1 W (W: Watts)
Pmech=E/t

Theory	Calculation
Electrical Power Equals Current times Voltage	Pmech= Pelect I= Pmech/V
Pelect=I V	I=1.1W/9V=0.12A

Theory	Calculation
Info: Typical 9-V Battery provides 0.1-A Current	Stick with One Battery (will replace after run)

Theory	Calculation
Info: Power Conversion Efficiency=0.5	Pmech= 0.5 х Pelect Use Two Batteries

Total Cost of Paint to Cover a Vehicle example:

-Sketch of Sections to Be Painted: hood, trunk, roof, side fenders

(From Horenstein)

-Estimate of the Area of Each Section

Hood	1.2m х 1.2m≈1.4m^2
Trunk	1.2m х 1.5m≈1.8m^2
Doors	2 х 1m х 0.8m≈1.6m^2
Roof	1.4m х 1.2m≈1.7m^2
Front fenders	2 х [0.4m х 1.5m + 1.5m х (0.8m-0.4m)] =2.4 m^2
Rear fenders	2 х [0.4m х 1m + 1.5m х (0.8m-0.4m)] =2.4 m^2

Total Area=10.9 m² A=bc+c(a-b)/2

(From Horenstein)

-Paint Volume

=Total Area χ Paint Thickness

=10m² χ 4mils χ ( 25 10^-6 m/mil)=0.001m³=1L

Overview: Engineering design tools:

-Brainstorming √

-Engineer’s Logbook: Documentation √

-Estimation √

-Prototyping

-Reverse Engineering

-Project Management

Prototyping

Prototype

-Preliminary version of final product without nonessential features

-Not durable

-Not visually attractive

System	Prototype
-Electronic Circuit	On a breadboard
-Mechanical	Built with wood; angle iron
-Large structures: buildings, bridges, dams,	Scale modeling; extrapolate (not always possible)

Peak-Performance Design Competition example:

Electronic timer as a stopping device(Tina)

Produced voltage during 7s

Run and stopped motor after 7s

Same for drive shaft and wheels in midair

Car traveled short on an inclined plane

Monitored battery voltage & current

Midair: I=0.04A; V=8.2V

On inclined plane: I=0.16A;V=3.9V

Six 1.5-V batteries in series

Overview: Engineering design tools:

-Brainstorming √

-Engineer’s Logbook: Documentation √

-Estimation √

-Prototyping √

-Reverse Engineering

-Project Management

Reverse Engineering

-Dissecting a product to learn how it works

-Helps avoiding patent infringement

Overview: Engineering design tools:

-Brainstorming √

-Engineer’s Logbook: Documentation √

-Estimation √

-Prototyping √

-Reverse Engineering √

-Project Management

Project Management

-Organizational Chart

-Time Line

9/12	Project 1 assigned Brainstorming session
9/14	Web and literature search
9/19	First prototype; testing
9/21	Progress report due
9/26	Redesign and testing
9/28	Written documentation
10/3	Competition/Presentation
10/5	Competition/Presentation

-Gantt Chart

	9/12	9/14	9/19	9/21	9/26	9/28	10/3	10/3
Brainstorming
Web & Lit search
First prototype; test
Progress report due
Redesign and test
Written document
Competition/Show