1. Aerodynamics and Velomobiles The 2005 Great Midwestern Velomobile and HPV Festival Eastern Iowa Environmental Innovators Organization (EIEIO) Nickolas Hein 11 June 2005

2. Wind Resistance Effective Frontal Area - CdA (sq ft) Speed (mph) Speed = 33 (CdA) 1/3 Unfaired Bikes Partial Fairings Full Fairings

3. Acceleration Equation for Human Power (Acceleration as a fraction of Gravity) a g = (P/W) -  V 2 ) V (W/C d A) V mph = (P/W) or V = 138 Low Speed  W*Slope V mph =  2P  1/3 or 33 High Speed  C d A  (CdA) 1/3 Power Rolling Fric. SlopeWind Resistance

4. Drag Effect of Openings in the Fairing

5. Coast-Down Tests Representative Hill

6. Fairing Layout

7. Speeds for Streamlined vs. Unfaired Vehicle   Vehicle 1 Unfaired UprightVehicle 2 Hypothetical Faired Streamlin Weight25 lbWeight50 lb C d A4 sq ftC d A1 sq ft

8. Plotted Results Streamlined (blue) and unfaired (red) vehicles – starting uphill from rest.

9. Phase Plot

10. Phase Plots Phase Plots for Unfaired and Fully-Faired Vehicles - Constant Pedalling

11. Aerodynamic Fairings for Velomobiles Objectives ->Performance Objective Utility Objectives Methods DesignLow DragLow Sideforce Downforce Cooling Textbooks Rules of Thumb Simulation ConstructionVerify DesignQuick & Cheap Modifiable Light Appearance Durability Rigid Sheet (Coroplast) Tube Frame and Fabric Foam Pad Fiberglass Vacuum Forming TestingResolve unpredicted problems Minimize Drag and separation Handling Qualities Coast-down test Smoke Tufts and

12. Weights of Construction Materials Solid Materials (lb / cu ft) –Steel 500 –Aluminum140 –Oak40 –Spruce20 –Plastic10-40 –Foam1-6 –Balsa6 Sheet Materials (lb/sq ft) –Kevlar/Nomex1 –Lexan (2 mm)1 –Coroplast.125 –Foam/Glass~.06 (Typical fairing has about 40 sq. ft. of total area)

13. Conclusions That concludes this presentation. Questions?

14. Bibliography 1) Design of Ground Vehicles - J Y Wong. c1993. Hardcover, 2nd ed., 464pp. Publisher: John Wiley & Sons, Incorporated. (Available from Barnes & Noble or Amazon.com for $100-110). Recommend getting this from a library. 2) Theory of Wing Sections - Ira H. Abbott and Albert VonDoenhoff. c1959. Dover Publications (Available from Barnes & Noble or Amazon.com for $12-15). Recommend getting buying this book. 3) Human Powered Vehicles - Edited by Allan Abbott and David Gordon Wilson. c1995. Publisher: Human Kinetics (800-747-4457). (Amazon.com lists it as being back- ordered at $45 so try getting it directly from the publisher instead.) Recommend buying this book. 4) Foundations of Aerodynamics - Arnold M. Kuethe and Chuen-Yen Chow. 5th Edition c1997. Publisher: John Wiley & Sons. (Available from Barnes & Noble or Amazon.com for $90-100). Recommend getting this from a library, any edition will do, I reference page nos. from the 3rd edition. 5) Bicycling Science - Frank Rowland Whitt and David Gordon Wilson. 2nd Edition c1982 Publisher: MIT Press. Recommend buying this in the newest edition.