Lab 07: System Analysis 3 (Wind Tunnel Testing)

Advanced Energy Vehicle

Piaggio Avanti!Fun Fact: The P.180 Piaggio Avanti’s wings, canard and propeller were designed and tested at The Ohio State University helping make this plane one of the world’s most efficiency propeller driven planes in the world! These tests were similar to the ones that will be conducted in today’s lab!

AEV Project Objective(Problem Definition)

INITIAL CONCEPTS(Brainstorming)

EXPERIMENTAL RESEARCH

ANALYZE

DESIGN DECISION

RESEARCH

COMPARE

FINAL DESIGN

Present AEV Design

PT 1PT 2PT 3PT 4

(System Analysis)(Programming)

Lab Objectives/Goals The objectives of this lab are:• Become familiar with propulsion system efficiency• Become familiar with wind tunnel testing

equipment

How to relate AEV to real-life objects

How to link wind tunnel testing to the AEV

Propulsion Efficiency Does input power supplied to the motors equal the

output power generated by the electric motors and propeller?

Input power = Power supplied to the vehicle’s propulsion system

Output power = Power generated by the electric motors and propellers

PowerInput Power

Independent variable: Current

Output Power (or Power Available) Dependent variables: Propeller RPM and the AEV’s

velocity

Units Output Power is a Mechanical System • Typical Units are: ???• Hint: when you ask for a car’s power is it given in units of

… ??

Input Power is an Electrical System• Typical Units are: ???• Hint: when you look up your light bulb’s power, it is given in

units of … ??

Answer: Horsepower

Answer: Watts Watts does NOT equal horsepower so the need to

convert horsepower to watts using the AEV Lab Manual

Advance Ratio Since Power Output (Available) is a function of two

independent variables, a new non-dimensional parameter was created to related all the variables using Buckingham Pi Theorem

This non-dimensional parameter is called Advanced Ratio and is commonly used in Aerospace Engineering:

How does this relate to AEV? Looking at a plot of Propulsion Efficiency vs Advance Ratio

How does voltage affect the propulsion efficiency

RPM is directly proportional to voltage

Increasing Voltage

How does this relate to AEV? Looking at a plot of Propulsion Efficiency vs Advance Ratio

Where is the 2 volts A or B?

2 volts divided by a 7.4 volt battery is approximately equivalent to 27% MotorSpeed

A

B

Configuration Selection

Puller (Tractor) Configuration

Pusher Configuration

Looking back at Piaggio Avanti back on the second slide, what is its configuration? Answer: Pusher!

Also look at the affect of the two sides of the propeller, there is a right and wrong way to put on a propeller!

Thrust Line Thrust Line

Quick Introduction on SetupPower Supply Velocity

Speed Indicator

Thrust Stand Data

Acquisition

Arduino Control System

Wind Tunnel Speed Control

Questions to think about . . . Things to think about during the Lab:• How do the values you obtain for power available of the

AEV’s motors compare to a typical car? Are the values reasonable?

• How do the values you obtain for input power of the AEV compare to a household light bulb? Are the values reasonable?

• What is the advance ratio needed to obtain the highest efficiency and how does that relate to power needed?

• Do all propellers have the same performance for all voltages/configurations?

Questions?