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Vacanti Yacht Design LLC FOIL Design and Analysis program provides a Windows CAD user interface and CAD file export for the well known Eppler Analysis code package. Valid for Reynolds Number (Less than 10 million) operation on Virtually all Sail and Power design applications.

If a new keel requires the minimum wetted surface (reduce friction drag) which foil shape do you choose? NACA 63? 64? 00? A new design? Which of these foils is least likely to stall when used as a rudder? Which of these foils would work best as a high speed center board in a tri or cat? Which offers the greatest strength as a centerboard? Which foil to use as a wing mast section for low drag and high strength? Which is the best for a new sailing dinghy centerboard? Which shape is best as a keel bulb? When is a keel or rudder too thick or thin?

ALL of these questions and many more can be answered by the program FOIL using state-of-the-art b-splines to define shapes and proven NASA code (Known as the Eppler Code) for performance prediction. A design cycle would work something like this - A foil is needed to provide the maximum ballast volume in a keel while keeping the wetted surface minimized. Design a foil with a high area coefficient that works over the desired ranges of speed, thickness and chord length. Verify lift and drag characteristics. Export the foil shape as a file to be read by WINGS or LOFT to design the keel. To make foil design easier and faster, the foil shape, fairing curves, area coefficient, position and amount of thickness are ALL updated as a b-spline vertex is moved with the mouse. FOIL computes percent change in Lift, Drag and Lift to Drag Ratio, making it easy to determine the benefit or detriment of each foil shape change relative to its initial shape. Some additional features of FOIL include:

Symetric or Cambered Foils
Spreadsheet Data Editor for reference foil offsets
Calculate Lift, Drag, Turbulence and Separation, Lift to Drag Ratio, Area Coefficient, Relative Velocity, REYNOLDS Number, Bubble Formation
Analyze TRIM TABS effect on LIFT/DRAG etc.
Calculations at 5 Reynolds Numbers and 13 Angles of Attack Scale overall foil thickness
Use Existing NACA or NASA foils as References or starting point to design a new foil
Foil fairing using slope and curvature curve plots.
Auto-Fit NURB splines to existing foil data
High Quality Printed Reports and Plots.
Capture Performance plots as BMP graphics files.
Calculates 48 Offset Values (NACA provides only 26)
Calculate foil performance over Reynolds Numbers between 250,000 and 10 million
Output TXT- Eppler Format, DXF, CDL, or IGES NURB CAD for precision CNC applications in additiuon to printingall offsets and physical characteristics.
Export design files to WINGS and LOFT for complete design capability