1. JHU/APL & AIAA Baltimore Section
The Electric Cargo Plane Challenge An Aeronautics Challenge for the Middle and High School Classroom
Tom Milnes
JHU/APL & AIAA Baltimore Section
Paul Wiedorn
Wilde Lake HS & TEAM

2. AIAA Baltimore Section Support
Major Supporter of Maryland MESA
Judges for National Competition and MESA Days
Members of National Competition Committee
Up, Up, and Away Workshop
Workshops on MESA Aerospace Challenges
Classroom Visits
Career Workshops at BEYA Event
Funding for Classroom Projects
RC Airplane Program Pilot

3. AIAA Support for K-12 Educators
AIAA Grant Program
$200 per teacher, up to $1000 per school for K-12 Classroom projects related to Aerospace
Steps
Join AIAA for Free as an Educator Associate
Submit Online Application
Must conform to guidelines, Principal approval needed

4. Electric Powered Flight as a Learning Tool
Topics for Learning
Newton’s Laws, Forces and Torques, Conservation of Mass, Momentum, and Energy, DC Electronics, Dynamics, Kinematics, Propulsion, Energy Conversion, Aerodynamics, Gravity, Stability, Equilibrium, Drag, Lift, Friction

5. National Standards Science Standard B - Physical Science
Motions and Forces
Conservation of Energy and Increase in Disorder
Standard E - Science and Technology
Identify a problem or design an opportunity
Propose designs and choose between alternative solutions.
Implement a proposed solution.
Evaluate the solution and its consequences. Communicate the problem, process, and solution.

6. National Standards Technology Design
Standard 8. Students will develop an understanding of the attributes of design.
Standard 9. Students will develop an understanding of engineering design.
Standard 10. Students will develop an understanding of the role of troubleshooting, research and development, invention and innovation, and experimentation in problem solving.
Abilities for a Technological World
Standard 11. Students will develop abilities to apply the design process.
The Designed World
Standard 18. Students will develop an understanding of and be able to select and use transportation technologies.

7. Why Tethered Flight?
Radio Controlled Airplanes Can Be Problematic for School Use
Expensive Electromechanical Controls Needed
Large Airfield and Good Weather Needed
Tethered Flight Solves These Problems

8. Tethered Flight Concept
Power
Supply
Clear Packing Tape
Power
Pole
Flat
Speaker
Wire
Constrained Flight Path
Can be done Indoors
Expensive RC Equipment not needed

9. Electric Cargo Challenge
Part of the Maryland Engineering Challenges
Held at the Glenn L. Martin Maryland Aerospace Museum
Saturday February 20, 2010
Open to all Middle and High School Student

10. Electric Cargo Challenge
Maryland Engineering Challenges Rules
MESA Challenge Rules

11. Electric Cargo Plane Challenge
Must complete one lap of tethered flight with and without cargo about the power pole
Plane must be 8” off the ground at all times
Scoring
MESA
MEC
Oral 30
Written 55 20
Design 40
Performance
55 - Most Weight 50 - Next Most …
30 x Cargo/Best Cargo
TOTAL
180
100

12. What You Get MANDATORY Kelvin Electronics 850647 3-6V, 17000 RPM, .26A
$.79 each
OPTIONAL
Kelvin Electronics
$5.75 per set of 8

13. What’s Needed Power Pole - We recommend Kelvin 850747 - $175
AIAA Educator Grant Can Be Used to Fund
Power Supply
Model Train Variable DC Transformer

14. What’s Needed Wings - Pink or Blue Foam Board - Home Depot $12
Fuselage - Basswood or Graphite Kite Stay

15. The Four Forces
Lift
Thrust
Drag
Gravity

16. Out of Trim Center of Pressure (1/4 to 1/3 from leading edge of wing)
Lift
Rotation
Rudder
Thrust
Elevator
Drag
Weight
Center of Pressure (1/4 to 1/3 from leading edge of wing)
Center of Gravity (“Balance Point” of Aircraft)

17. Trimmed
Lift
Thrust
Drag
Gravity
Center of Pressure (CP) should Coincide with Center of Gravity (CG)
For Level Flight!! Use Rubber Bands to Achieve Adjustable Wings!

18. Where to Put Cargo Don’t Want to Change Trim of Airplane
Should Add Cargo Such that Center of Gravity (“Balance Point”) Does not move
Aerodynamic and Gravity Forces remain aligned so Airplane Remains Trimmed

19. Electrical Connections
propeller
clear tape
handset
plug
motor
main wing
+/- wire pair
3 feet maximum
10 feet minimum
fuselage
Electrical Connections
Green -
Yellow +
Black -
Red +
empennage
(View from Bottom)

20. How is Lift Generated?
Lift is generated when a solid object such as wing turns a moving flow downward
Newton’s Third Law
For Every Action there is an Equal and Opposite Reaction
ACTION - Air (which has mass and velocity) is directed downward
REACTION - Wing moves upward
The Bernoulli Effect is a Minor Component of Lift
About 1/10 of Total
Ignores Viscosity of Air
Causes Air to “adhere” the surface of the wing - “Coanda Effect”
Turning of Air about Leading Edge - “Leading Edge Suction” is the primary cause of Lift

21. Pressure on Airfoil
Leading Edge
Suction

22. Best Airfoil?
Best Wing Redirects Air Downward Without Slowing it Down.
To a point more redirection is better
After that point air will not remain “attached” to wing
Lift decreases and Drag increases “Stall”
Trick is to find optimum level of redirection
Angle of Attack
Even a flat plate will produce lift
Camber
Gentle curvature of wing
Thickness along Camber
Blunt Leading Edge
Tapered Trailing Edge
Maximum Thickness 1/3 way back

23. Best Wing? Should I Copy a Jet Airliner Wing?
NO - Aerodynamically Similar If
Since density and viscosity are constant for air want the product of Velocity and Length (vL) to be the same
Jet Aircraft are both Bigger and Faster - Performance Not The Same
Birds and Insect Wings are a Better Match
How Long Should the Wing Be?
Use maximum 3’ - Lift increases with area and L/D increases as wing span increases

24. “Turning In Problem” Weight Of Tether Greater Weight on Inner Wheel
Produces Greater Friction
Airplane Turns Inward

25. Practice, Practice
Successful teams will have experience flying, adjusting, and repairing planes
Unlikely to do well if your plane hasn’t been tested with power pole
Teachers can use AIAA Grant Program to Obtain Power Pole and Power Supply