The Electric Cargo Plane Challenge An Aeronautics Challenge for the Middle and High School Classroom

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The Electric Cargo Plane ChallengeAn Aeronautics
Challenge for theMiddle and High School Classroom

• Tom Milnes
• JHU/APL AIAA Baltimore Section
• Paul Wiedorn
• Wilde Lake HS TEAM

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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

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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
• https//www.aiaa.org/content.cfm?pageid208
• Submit Online Application
• https//www.aiaa.org/content.cfm?pageid216
• Must conform to guidelines, Principal approval
  needed
• https//www.aiaa.org/content.cfm?pageid244

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Electric Powered Flight as a Learning Tool

• Topics for Learning
• Newtons Laws, Forces and Torques, Conservation
  of Mass, Momentum, and Energy, DC Electronics,
  Dynamics, Kinematics, Propulsion, Energy
  Conversion, Aerodynamics, Gravity, Stability,
  Equilibrium, Drag, Lift, Friction

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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.

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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.

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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

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Tethered Flight Concept
Tether
Power Supply
Clear Packing Tape
Power Pole
Flat Speaker Wire

• Constrained Flight Path
• Can be done Indoors
• Expensive RC Equipment not needed

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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

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Electric Cargo Challenge

• Maryland Engineering Challenges Rules
• http//www.thebmi.org/index.cfm/cID/630
• MESA Challenge Rules
• http//www.jhuapl.edu/mesa/events/mesaday/competit
  ion.asp

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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

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What You Get
MANDATORY Kelvin Electronics 850647 3-6V, 17000
RPM, .26A http//www.kelvin.com .79 each
OPTIONAL Kelvin Electronics 990175 5.75 per set
of 8
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Whats Needed

• Power Pole - We recommend Kelvin 850747 - 175
• http//www.kelvin.com
• AIAA Educator Grant Can Be Used to Fund
• Power Supply
• Model Train Variable DC Transformer

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Whats Needed

• Wings - Pink or Blue Foam Board - Home Depot 12
• Fuselage - Basswood or Graphite Kite Stay

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The Four Forces
Lift
Drag
Thrust
Gravity
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Out of Trim
Lift
Rudder
Rotation
Thrust
Elevator
Drag
Weight
Center of Pressure (1/4 to 1/3 from leading edge
of wing)
Center of Gravity (Balance Point of Aircraft)
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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!
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Where to Put Cargo

• Dont 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

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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)
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How is Lift Generated?

• Lift is generated when a solid object such as
  wing turns a moving flow downward
• Newtons 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

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Pressure on Airfoil
Leading Edge Suction
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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

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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

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Turning In Problem
Weight Of Tether
Greater Weight on Inner Wheel Produces Greater
Friction Airplane Turns Inward
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Practice, Practice

• Successful teams will have experience flying,
  adjusting, and repairing planes
• Unlikely to do well if your plane hasnt been
  tested with power pole
• Teachers can use AIAA Grant Program to Obtain
  Power Pole and Power Supply