Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781720627098
Total Pages : 76 pages
Book Rating : 4.6/5 (27 download)
Book Synopsis Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics by : National Aeronautics and Space Administration (NASA)
Download or read book Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-03 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of vortex ring state (VRS) on rotorcraft flight dynamics is investigated, specifically the vertical velocity drop of helicopters and the roll-off of tiltrotors encountering VRS. The available wind tunnel and flight test data for rotors in vortex ring state are reviewed. Test data for axial flow, non-axial flow, two rotors, unsteadiness, and vortex ring state boundaries are described and discussed. Based on the available measured data, a VRS model is developed. The VRS model is a parametric extension of momentum theory for calculation of the mean inflow of a rotor, hence suitable for simple calculations and real-time simulations. This inflow model is primarily defined in terms of the stability boundary of the aircraft motion. Calculations of helicopter response during VRS encounter were performed, and good correlation is shown with the vertical velocity drop measured in flight tests. Calculations of tiltrotor response during VRS encounter were performed, showing the roll-off behavior characteristic of tiltrotors. Hence it is possible, using a model of the mean inflow of an isolated rotor, to explain the basic behavior of both helicopters and tiltrotors in vortex ring state.Johnson, WayneAmes Research CenterVORTEX RINGS; TILT ROTOR AIRCRAFT; HELICOPTERS; FLIGHT TESTS; ROTARY WING AIRCRAFT; MOMENTUM THEORY; WIND TUNNEL TESTS; DROP TESTS; COMPUTERIZED SIMULATION