N 8 8-1663 0 Comprehensive Rotorcraff Analysis Methods
The paper describes the development and application of comprehensive rotorcraft analysis methods in the field of rotorcraft technology. These large scale analyses and the resulting computer programs are intended to treat the complex a_'.romechanicM phenomena that describe the behavior of rotorcraft. They may be used to predict rotor aerodynamics, acoustics, performance, stability and control, handling qualities, loads and vibrations, structures, dynamics, and aeroelutic stability characteristics for a variety of applications including research, preliminary and detail design, and evaluation and treatment of field problems. The principal comprehensive methods developed or under development in recent year1 and generally available to the rotorcraft community because of US Army Aviation Research and Technology Activity (ARTA) sponsorship of all or part of the software systems are the Rotorcraft Flight Simulation (C81), Dynamic System Coupler (DYSCO), Coupled Rotor/Airframe Vibration Analysis Program (SIMVIB), Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD), General Rotorcraft Aeromechanical Stability Program {GRASP}, and Second Generation Comprehensive Helicopter Analysis System (2GCHAS). 312 https://ntrs.nasa.gov/search.jsp?R=19880007247 2018-04-23T06:50:56+00:00Z
Use of rotorcraft computer analysis for U.S. government design assessment
Abstract Rotorcraft Computer Analysis is used by the U.S. Government to evaluate independently new concepts and responses to request for proposals (RFPs). This paper will describe how it is used during concept formulation and on source selection evaluation boards (SSEBs), why it is essential, and how it must be integrated with other considerations. The Army Helicopter Improvement Program (AHIP) SSEB and the LHX Concept Formulation effort will be used as examples.
Experimental investigation of effects of blade tip geometry on loads and performance for an articulated rotor system
Wind-tunnel tests of an aeroelastically designed helicopter rotor model were carried out to determine the effects on dynamic response and aerodynamic performance of varying the design of the outboard 8 percent of the blade lengths. Four different blade tip geometries or shapes having different amounts of planform sweep, thickness and chordwise taper, and anhedral angle were studied. Each configuration was tested at several shaft angles of attack for advance ratios of 0.20, 0.30, 0.35, and 0.40. For each combination of shaft angle and advance ratio, rotor lift was varied over a wide range to include high lift conditions.