PRODUCTS   EHPIC/HERO

Evaluation of Hover Performance using Influence Coefficients/
HElicopter Rotor Optimization


EHPIC/HERO is an extremely fast and accurate analysis tailored specifically for rotor blade design. For over a decade, EHPIC/HERO has been used extensively by helicopter manufacturers in major rotor blade design efforts, such as the RAH-66 Comanche and AARP Apache blade designs. The key to EHPIC/HERO's success is its unique influence coefficient approach which allows the determination of the force free wake solution about which the inherent hovering wake instability develops. It has been shown that this approach allows for quick optimization of the average rotor performance characteristics in hover, a critical design point for most applications. For prediction of hover or axial flight performance and rotor blade optimization, EHPIC/HERO is unsurpassed in terms of speed and accuracy, as evidenced by several studies cited below. EHPIC/HERO is also available for the design of propellers and wind turbines. Please wait while movie is being loaded...


Some EHPIC/HERO Applications
  • Design of Variable Diameter Tilt Rotor - Sikorsky Aircraft
  • Design of RAH-66 Comanche rotor blades - Sikorsky Aircraft/Boeing Helicopters
  • Design of Future V-22 rotor blade concepts - Boeing Helicopters/CDI
  • Design of the AARP Affordable Apache Rotor Blades - Boeing Mesa
  • Design of new improved S-61 rotor blades - Carson Helicopters/CDI
  • Design of the Schiebel Camcopter S-100 UAV Main Rotor Blade - CDI


Some EHPIC/HERO Published Studies
  • Felker, F.F. 1993: "Accuracy of Tilt Rotor Hover Performance Predictions," NASA TM-104023, June.
  • Davis, S.J., Moffitt, R., Quackenbush, T.R., and Wachspress, D.A. 1995. "Aerodynamic Design Optimization of a Variable Diameter Tilt Rotor," AHS 51st Annual Forum Proc., Vol. 1, Fort Worth, TX, May 9-11, pp. 101-111.
  • Felker, F. F., Quackenbush, T. R. and Bliss, D. B. 1990. "Comparisons of Predicted and Measured Rotor Performance in Hover Using a New Free Wake Analysis," Vertica, Vol. 14, No. 3.
  • Light, J.S. 1989. "Tip Vortex Geometry of a Hovering Helicopter Rotor in Ground Effect," AHS 45th Annual Forum Proc., Boston, MA, 22-24 May, pp. 551-562.
  • Quackenbush, T.R., Wachspress, D.A. and Kaufman, A.E. 1991. "Optimization of Rotor Performance in Hover Using A Free Wake Analysis," Journal of Aircraft, Volume 28, No. 3, March.
  • Quackenbush, T.R., Boschitsch, A.H., Wachspress, D.A. and Chua, K 1993. "Rotor Design Optimization using a Free Wake Analysis," NASA Contractor Report 177612, April.
  • Shanley, J. P., Moffitt, R. C. and Davis, S. J. 1990. "Systematic Correlation and Evaluation of the EHPIC Hover Analysis," AHS 46th Annual Forum Proc., Washington D.C., May 21–23, pp. 1121-1134.
  • Swanson, A.A. and Light, J.S, 1992. "Shadowgraph Flow Visualization of Isolated Tiltrotor and Rotor/Wing Wakes", AHS 48th Annual Forum Proc., Washington D.C., June 3–5, pp. 1323-1344.
  • Tung, C. and Lee, S. 1994. "Evaluation of Hover Performance Prediction Codes," AHS 50th Annual Forum Proc., Washington D.C., May 11–13, pp. 829-844.
  • Janakiram, R., Smith, R., Charles, B. Hassan, A. 2003. "Aerodynamic Design of a New Affordable Main Rotor for the Apache Helicopter," AHS 59th Annual Forum Proc., Montreal, Canada, May 25–27, pp. 526-542.
For further information, contact Dan Wachspress at CDI (609) 538-0444 x114.