Project Title:

Performance Optimization for Rotors in Hover and Axial Flight

02.10-9282
Performance Optimization for Rotors in Hover
	and Axial Flight
Continuum Dynamics, Inc.
PO Box 3073
Princeton, NJ 08543
Todd R. Quackenbush  (609-734-9282)
ARC -- NAS2-12789

Abstract:

	 The rotorcraft community has a continuing need for improved design techniques for
hover and axial flight. Such techniques can be employed to best advantage if they
are coupled with numerical optimization methods to reduce the trial and error computations
when searching for configurations to meet particular design specifications. A new,
highly advanced, hover-performance analysis, EHPIC (Evaluation of Hover Performance
using Influence Coefficients), recently developed by the firm, seems well-suited
to the development of an optimization analysis. As a by-product of the solution method,
arrays of influence coefficients relating the rotor loads and wake geometry to the
down-wash are generated. These arrays are useful in the development of an optimization
scheme.
	The Phase I effort demonstrated that a numerical optimization algorithm could be
coupled to the EHPIC code to produce rotors with substantially improved performance.
The coupling was accomplished by expanding the matrix of linear influence coefficients
in EHPIC to accommodate design variables and deriving coefficients for linear equations
governing perturbations in power and thrust. Using the rotor power as an objective
function and introducing constraints on the design variable perturbations, a sequential
linear optimization analysis was formed that was invoked to predict changes in the
twist distribution that produced reductions in power at constant thrust for a variety
of rotor configurations in hover and axial flight.

Potential Commercial Application:

Potential Commercial Application: Applications will be by researchers in the government
and rotorcraft designers in industry.