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Project Cadence. Adam Christensen Mordechai Cohen Amoz Eckerson John Vesely. Inspiration. Dempsey – MacCready Hour Record Prize Maximize distance traveled in 1 hour Powered by a single human being. 20 miles in 1 hour. 30 miles in 1 hour. Project Goals.
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Project Cadence Adam Christensen Mordechai Cohen Amoz Eckerson John Vesely
Inspiration Dempsey – MacCready Hour Record Prize • Maximize distance traveled in 1 hour • Powered by a single human being
20 miles in 1 hour 30 miles in 1 hour Project Goals • First step toward the Dempsey – MacCready Hour Record Prize • Design a human powered vehicle (HPV) for 150% of current rider capabilities
Aerodynamic Fairing Drivetrain Rider in Prone Position Frame Project Cadence HPV
Governing Equation Power Supply – Power Demand = Power for Acceleration Rolling Resistance Human Power Aerodynamic Drag Incline
P=VI Human Power • Understanding nature of human as a source of power • Not like a simple electric motor • Must be modeled • Work to improve ? • Training • Diet • Strategy Excessive for project scope Develop human power input as a function of time
NASA Human Power Curve • NASA curve was developed to show time until fatigue for “healthy men” • If output power is not constant, NASA curve cannot be used
Scaling Process Rider begins at output rate of 300W Max time = 4 min
Scaling Process Rider begins at output rate of 300W Max time = 4 min Rider goes for 2 min and is ½ way to exhaustion
Scaling Process Rider switches to output rate of 200W ORIGINAL max time = 60 min
Scaling Process Rider switches to output rate of 200W ORIGINAL max time = 60 min Adjustment is needed to account for the previous output
Scaling Process Rider switches to output rate of 200W ORIGINAL max time = 60 min Adjustment is needed to account for the previous output NEW max time = 30 min
Verification of Scaling Law 96.0% – 99.8% Accuracy
Adequately house the rider and vehicle Laminar flow (skin friction drag dominates) Minimize protuberance drag Consider ground effects Aerodynamics – Critical Design Parameters
Psarevo Shape NACA 66(4)-021 airfoil profile Camber Enclosed rear wheel Faired front wheel
Testing the Shapes CFD & Wind Tunnel Models Compare different fairing designs Investigate camber and ground effects Measure drag and determine values for CDA (a necessary input into our Energy Model)
Aerodynamics Skin friction drag of a flat plate 2D 3D
Torpedo Flat Tail (TFT) Torpedo 3D Empirical Relations CD = Skin Friction + Supervelocity + Separation Pressure
Composite Fairing – Psarevo Shape Approximated as a TFT with transition located at 60%
Project Cadence HPV Frame 4130 Steel tube 1 in OD x 0.035 in WT ½ in OD x 0.035 in WT Weight = 10.2 lbs
Project Cadence HPV Wheels & Tires Velocity Deep-V 20 in wheels 24 mm wide, 32 mm deep aero rim ACS RL Edge 20 in tires Crr1 = 0.0049
Project Cadence HPV Drivetrain 165 mm Crank arm 53 T Crank gear 30-28-22-16-11 T Cassette Geared for 32 mph at 60 rpm
Project Cadence HPV Hayes Hydraulic Disc Brake Ø 74 mm piston 6 in rotor
Project Cadence HPV Supports Walnut hip support Cushioned for comfort
Project Cadence HPV Complete Internal Structure
Design Considerations • Energy Model result: 32.9 miles in 1 hour • Strategy • Relax upwind, make up time downwind • Relax uphill, make up time downhill • Aerodynamic Benefits • Human Fatigue affects even a professional athlete
What is next? • Verify • Construct • Check • Predict • Test
Questions? Thank you Hayes Brake, LLC Jason Incorporated Lincoln Electric Milwaukee Electric Tool Modine Manufacturing NASA / Langley Full-Scale Wind Tunnel Rhino 3D Wheel & Sprocket
Why the MSOE Wind Tunnel Will Not Work • Need to preserve Reynolds number when going from full-scale to something smaller • MSOE One-Sixth Scale Wind Tunnel
How to deal with Weight Power Supply – Power Demand = Power for Acceleration Weight also affects the Power for Acceleration • Initial acceleration to speed • Incremental acceleration around the track Rolling Resistance Acceleration Power Incline