Hanley Innovations
VisualFoil Plus
PO Box 831514
Ocala, FL 34483

VisualFoil Plus Improves Propeller Performance

Read how your company can use  VisualFoil Plus to improve the design of aircraft propellers.

Propellers rapidly loose efficiency over a narrow range of helical tip Mach number in the transonic regime. This limits the thrust produced by a given power plant and sets an upper limit on the operational airspeed of the aircraft.

Rapid loss of efficiency at high subsonic mach numbers is due in part to compressibility effects. At a given station along the propeller diameter, the drag coefficient generated by the blade cross section can rapidly increase over a narrow speed range. In addition, the cross section may generate a negative lift at higher mach numbers which can compound the problem.

The following solution procedure is recommended:

  • Use VisualFoil Plus to compute the lift and drag coefficients generated by the blade cross sections at various stations along the propeller diameter.
  • Use the results from VisualFoil Plus to generate a chart of drag coefficient versus sectional helical Mach number to determine the drag divergence Mach number for each station.
  • Determine if the drag divergence Mach number for each section falls within the desired (design) operational envelope of your propeller.
  • Use the airfoil modification features of VisualFoil Plus to fix the blade cross section and increase the drag divergence Mach number for the problem sections.

About VisualFoil Plus
VisualFoil Plus is an easy-to-use software package for analyzing airfoils in both incompressible & compressible flows. The incompressible flow analysis is based on a fast linear-strength vortex-panel solver coupled with an ODE boundary layer solver. The compressible analysis is based on a finite volume (FV) Euler equations solver based on either flux vector splitting for flux difference splitting. The o-grid is generated automatically and the solution converges within seconds to a few minutes (depending on the grid resolution) on an ordinary Pentium based PC. Prices for VisualFoil Plus start at $695 for the 3 months lease. More information can be found at http://www.hanleyinnovations.com.


  1. Patrick Hanley, Ph.D. "High Speed Blade Screening"
  2. Julian D. Maynard and Seymoour Steinberg, "The Effect of Blade-Section Thickness Ratios on the Aerodynamics Characteristics of Related Full-Scale Propellers at Mach Numbers up to 0.65", NACA Report 1126.
  3. Julian D. Maynard and Leland B. Salters, Jr., "Aerodynamic Characteristics at High Speeds of Related Full-Scale Propellers having Different Blade-Section Cambers", NACA Report 1309.
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