Mid-Term Presentation

1. Mid-Term Presentation Ben Holohan Syrus Jeanes Karl Lindman Stephan Mehling Rob Radomski Ted Simeoni Steven Bukowsky Chris Buonocore Anthony Costantini Joshua Gauvin Michael Hanlon Omar Hayan Marco Herrera

2. Overview • Project Goals & Objectives • Design Process • Objectives • Models and Calculations • Wind Tunnel Tests & Results • Testing and Fabrication • Accomplishments • Fall Semester Goals

3. Project Goal and Objectives Mission: To demonstrate potential uses of Channel Wings by proving VTOL capability Goals: • Design Prototype Aircraft • Design and Construct Prototype Wing For Testing Purposes • Design and Construct Complete Working Prototype • Perform Flight Tests Using Prototype Model • Refine Prototype Through Wind Tunnel Tests and Construct Dedicated VTOL Aircraft • Add Payload for Distinct Missions

4. Objectives Effective Span • Test several wings in tunnel • 9 in straight • 14.15 in straight • 9 in channel • Compare Cl vs. AOA data with known airfoil plots for straight wings • Find Lift of Channel and calculate effective span

5. Objectives http://www.cerfacs.fr/cfd/FIGURES/IMAGES/airfoil1_big.jpg Location of Aero Center • Use 16 point Pressure Transducer to determine Pressure Profile • Vary AOA for pressure profile test • Use Pressure Profile to calculate Moments • Knowing Ma/c is constant for any AOA, find location of a/c http://www.ruander.com/wp-content/uploads/2008/04/airfoil-pressure20.jpg

6. Objectives Velocity Profile • Use Boundary Layer Survey program in wind tunnel • Attach motor and prop to channel • Assume steady level and set tunnel speed based on Thrust • Determine Velocity Profile from Pressure Profile http://cfl3d.larc.nasa.gov/Cfl3dv6/2DTestcases/N0012/cp.t0.gif

7. αtm Lt Lw Dt Mac(t) Ref point αwm αwm ctail T zt α-ε zcp Mac(w) Dw zcg v ’ α xac(w) v∞ W c hcg ht Objectives Stable Flight • Use appropriate simplifications • Generate Flight Envelope to satisfy Static Longitudinal Stability • Generate Flight Envelope to satisfy Static Rolling Stability

8. Objectives VTOL (Vertical Take-Off and Landing) • Use effective span to calculate Lift of channel • Calculate Thrust of motor/prop combination • Find Resultant of two vectors such that magnitude is L=W and find AOA • Achieve Maximum Lo/To

9. LSW = LCW = FDc force F distributed evenly Models and Calculations • Initial Lift Analysis • Assume lift from channel wing equal to that of a straight wing with a length equal the channel’s diameter

10. R = T sin(α)+L cos(α) T L α α = tan-1(T/L) Models and Calculations • VTOL Angle Determination • VTOL angle (α) dependent on ratio of T to L. Low VTOL angle means most benefit from channel.

11. A = Ap = πD2/4 p∞ u∞ p2 = p∞ u2 > u∞ p+ p∞ p∞ p- u2 up = (u2 + u∞)/2 u∞ Models and Calculations Froude Momentum Theory Analysis • Replace propeller with disc, which creates pressure differential. Assumptions: • Steady, 1-D, incompressible flow. • Neglect prop wash rotation.

12. Models and Calculations Froude Momentum Theory Analysis Conservation of Mass • First step in derivation • Yields expressions needed in subsequent derivations

13. Models and Calculations Froude Momentum Theory Analysis Conservation of Momentum • Yields expression for Thrust • Yields expression for Velocity at propeller disc

14. Models and Calculations Froude Momentum Theory Analysis Conservation of Energy • Yields expression for Power required • Important for motor and propeller selection

15. Models and Calculations x=0 Δp x=-c Lift, Moment and Location of Center of Pressure • Wing represented as curved plate of flat section • Assume wing interference is negligible • Since static lift is independent of α, CP is significant location • Lift from free stream airflow is taken at AC

16. Models and Calculations Preliminary Momentum Theory Applications

17. Models and Calculations Preliminary Momentum Theory Applications

18. Models and Calculations Comparison Test for Effective Span • 9 in and 14 in straight wing tested to establish lift curve • Significant inconsistencies in data • Zero – AOA issues • Consulted with Dr. Subramanian and Dr. Kirk • Established new testing procedure • Subsequent tests to use new procedure • Affords far greater consistency • Procedure set for full round of testing

19. Models and Calculations Average Lift Slope = 0.0460 Corrected Slope = 0.0639

20. Models and Calculations Average Lift Slope = 0.0784 Corrected Slope = 0.0716

21. Testing and Fabrication Wing Construction • Primarily balsa construction • Fixture used to obtain correct diameter channel

22. Testing and Fabrication • Stiffening stringers sanded smooth with wing ribs • Carbon fiber spar for support and mounting

23. Testing and Fabrication Fuselage Construction • Primarily balsa construction • Bulkheads and stringers for support • Easy access to batteries and electronics

24. Testing and Fabrication • Prove channel lift theory • Measure how much lift is produced

25. Testing and Fabrication Current Construction Goals • Finish construction of lift stand • Build Alpha Prototype

26. Accomplishments • Channel Wing and Fuselage tested structurally. Gained manufacturing experience. • 9 and 14 in straight wings constructed • Wind Tunnel testing started

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28. Fall Semester Goals • Alpha Prototype • Wind Tunnel Test, Recorded data, and Stability Analysis • Wing and Propeller Velocity Profile • Effective Span of Channel Wing • Wind Tunnel Testing Guidelines • Determination of Effective Span • Channel Wing Lift curves • Difficulties and Lessons Learned • Manufacturing Process • Channel Wing (frame, ribs, spar, and fuselage assembly) • Lift Stand for Channel Wing Lift Test (Concept Demonstrator) • Concept Assessment • Benefits of Channel Wing • Difficulties, Risks, and Improvements • Beta( VTOL Prototype) • Channel Wing Deliverable Questions? 28