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

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

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?pageid=208 Submit Online Application https://www.aiaa.org/content.cfm?pageid=216 Must conform to guidelines, Principal approval needed https://www.aiaa.org/content.cfm?pageid=244

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

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.

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.

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

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

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

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/competition.asp

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

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

What’s 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

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

The Four Forces Lift Thrust Drag Gravity

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)

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!

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

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)

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

Pressure on Airfoil Leading Edge Suction

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

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

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

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

Submitted for – www.mycollegebag.in