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Advanced Energy Vehicle
Lab 07: System Analysis 3 (Wind Tunnel Testing)
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
(Programming)
(System Analysis)
PT 1
PT 2
PT 3
PT 4
FINAL DESIGN
Present AEV Design
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?
𝑂𝑢𝑡𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟
𝑃𝑟𝑜𝑝𝑢𝑙𝑠𝑖𝑜𝑛 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 % =
∗ 100%
𝐼𝑛𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟
Input power = Power supplied to the vehicle’s propulsion
system
Output power = Power generated by the electric motors and
propellers
Power
Input Power
 Independent variable: Current
𝐼𝑛𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟 = 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 ∗ 𝑉𝑜𝑙𝑡𝑎𝑔𝑒
Output Power (or Power Available)
 Dependent variables: Propeller RPM and the AEV’s velocity
𝐼𝑛𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟 = 𝑇ℎ𝑟𝑢𝑠𝑡 ∗ 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 … ??
Answer: Horsepower
 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: 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:
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦
𝐴𝑑𝑣𝑎𝑛𝑐𝑒 𝑅𝑎𝑡𝑖𝑜 𝐽 =
𝑅𝑃𝑀
∗ 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟
60
How does this relate to AEV?
 Looking at a plot of Propulsion Efficiency vs Advance Ratio
 How does voltage
affect the
propulsion
efficiency
𝐽=
𝑉
𝑅𝑃𝑀
∗𝐷
60
 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
B
A
Configuration Selection
Thrust Line
Puller (Tractor) Configuration
Thrust Line
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!
Quick Introduction on Setup
Power Supply
Velocity Speed
Indicator
Wind Tunnel
Speed Control
Thrust Stand Data
Acquisition
Arduino Control
System
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?