Download or read book Forebody Aerodynamics of the F 18 High Alpha Research Vehicle with Actuated Strakes written by and published by . This book was released on 2003 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive pressure measurements and off-surface flow visualization were obtained on the forebody and strakes of the NASA F-18 High Alpha Research Vehicle (HARV) equipped with actuated forebody strakes. Forebody yawing moments were obtained by integrating the circumferential pressures on the forebody and strakes. Results show that large yawing moments can be generated with forebody strakes. At a 500-angle-of attack, deflecting one strake at a time resulted in a forebody yawing moment control reversal for small strake deflection angles. However, deflecting the strakes differentially about a 200 symmetric strake deployment eliminated the control reversal and produced a near linear variation of forebody yawing moment with differential strake deflection. At an angle of attack of 500 and for O% and 200 symmetric strake deployments, a larger forebody yawing moment was generated by the forward fuselage (between the radome and the apex of the leading-edge extensions) than on the radome where the actuated forebody strakes were located. Cutouts on the flight vehicle strakes that were not on the wind tunnel models are believed to be responsible for deficits in the suction peaks on the flight radome pressure distributions and differences in the forebody yawing moments.

Download or read book Effect of Actuated Forebody Strakes on the Forebody Aerodynamics of the NASA F 18 Harv written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive pressure measurements and off-surface flow visualization were obtained on the forebody and strakes of the NASA F-18 High Alpha Research Vehicle (HARV) equipped with actuated forebody strakes. Forebody yawing moments were obtained by integrating the circumferential pressures on the forebody and strakes. Results show that large yawing moments can be generated with forebody strakes. At angles of attack greater than 40 deg., deflecting one strake at a time resulted in a forebody yawing moment control reversal for small strake deflection angles. At alpha = 40 deg. and 50 deg., deflecting the strakes differentially about a 20 deg. symmetric strake deployment eliminated the control reversal and produced a near linear variation of forebody yawing moment with differential strake deflection. At alpha = 50 deg. and for 0 deg. and 20 deg. symmetric strake deployments, a larger forebody yawing moment was generated by the forward fuselage (between the radome and the apex of the leading-edge extensions), than on the radome where the actuated forebody strakes were located. Cutouts on the flight vehicle strakes that were not on the wind tunnel models are believed to be responsible for deficits in the suction peaks on the flight radome pressure distributions and differences in the forebody yawing moments. Fisher, David F. and Murri, Daniel G. and Lanser, Wendy R. Unspecified Center RTOP 505-68-30...

Download or read book A Method for Integrating Thrust Vectoring and Actuated Forebody Strakes with Conventional Aerodynamic Controls on a High Performance Fighter Airplane written by Frederick J. Lallman and published by . This book was released on 1998 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Forebody Flow Visualization on the F 18 HARV with Actuated Forebody Strakes written by David F. Fisher and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Off-surface smoke flow visualization and extensive pressure measurements were obtained on the forebody of the NASA F-18 High Alpha Research Vehicle equipped with actuated forebody strakes. Test points at [alpha]=50 deg. were examined in which only one strake was deflected or in which both strakes were deflected differentially. The forebody pressures were integrated to obtain forebody yawing moments. Results showed that small single strake deflections can cause an undesirable yawing moment reversal. At [alpha]=50 deg., this reversal was corrected by deploying both strakes at 20 deg. initially, then differentially from 20 deg. to create a yawing moment. The off-surface flow visualization showed that in the case of the small single strake deflection, the resulting forebody/strake vortex remained close to the surface and caused accelerated flow and increased suction pressures on the deflected side. When both strakes were deflected differentially, two forebody/strake vortices were present. The forebody/strake vortex from the larger deflection would lift from the surface while the other would remain close to the surface. The nearer forebody/strake vortex would cause greater flow acceleration, higher suction pressures and a yawing moment on that side ot the forebody. Flow visualization provided clear description of the strake vortices fluid mechanics.

Download or read book Effect of Actuated Forebody Strakes on the Forebody Aerodynamics of the NASA F 18 HARV written by David F. Fisher and published by . This book was released on 1996 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Summary of the Forebody High angle of attack Aerodynamics Research on the F 18 and the X 29A Aircraft written by and published by . This book was released on 1992 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Tunnel Investigations of Forebody Strakes for Yaw Control on F A 18 Model at Subsonic and Transonic Speeds written by Gary E. Erickson and published by . This book was released on 1993 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation Model of the F A 18 High Angle of attack Research Vehicle Utilized for the Design of Advanced Control Laws written by Michael D. Messina and published by . This book was released on 1996 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 'f18harv' six degree-of-freedom nonlinear batch simulation used to support research in advanced control laws and flight dynamics issues as part of NASA's High Alpha Technology Program is described in this report. This simulation models an F/A-18 airplane modified to incorporate a multi-axis thrust-vectoring system for augmented pitch and yaw control power and actuated forebody strakes for enhanced aerodynamic yaw control power. The modified configuration is known as the High Alpha Research Vehicle (HARV). The 'f18harv' simulation was an outgrowth of the 'f18bas' simulation which modeled the basic F/A-18 with a preliminary version of a thrust-vectoring system designed for the HARV. The preliminary version consisted of two thrust-vectoring vanes per engine nozzle compared with the three vanes per engine actually employed on the F/A-18 HARV. The modeled flight envelope is extensive in that the aerodynamic database covers an angle-of-attack range of -10 degrees to +90 degrees, sideslip range of -20 degrees to +20 degrees, a Mach Number range between 0.0 and 2.0, and an altitude range between 0 and 60,000 feet.

Download or read book Effect of Actuated Forebody Strakes on the Forebody Aerodynamics of the NASA F 18 HARV written by David F. Fisher and published by . This book was released on 1996 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using the HARV Simulation Aerodynamic Model to Determine Forebody Strake Aerodynamic Coefficients from Flight Data written by Michael D. Messina and published by . This book was released on 1995 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The method described in this report is intended to present an overview of a process developed to extract the forebody aerodynamic increments from flight tests. The process to determine the aerodynamic increments (rolling pitching, and yawing moments, Cl, Cm, Cn, respectively) for the forebody strake controllers added to the F/A - 18 High Alpha Research Vehicle (HARV) aircraft was developed to validate the forebody strake aerodynamic model used in simulation.

Download or read book High Alpha Research Vehicle Lateral Directional Control Law Description Analyses and Simulation Results written by John B. Davidson and published by . This book was released on 1998 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Flight control System Development for the F 18 High Alpha Research Vehicle written by and published by . This book was released on 1991 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flight Determined Subsonic Lateral Directional Stability and Control Derivatives of the Thrust Vectoring F 18 High Angle of Attack Research Vehicle HARV and Comparisons to the Basic F 18 and Predicted Derivatives written by Kenneth W. Iliff and published by . This book was released on 1999 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Validation of the F 18 High Alpha Research Vehicle Flight Control and Avionics Systems Modifications written by and published by . This book was released on 1990 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Overview of the NASA F 18 High Alpha Research Vehicle written by Albion H. Bowers and published by . This book was released on 1996 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The F A 18 High Angle of Attack Ground to Flight Correlation Lessons Learned written by and published by . This book was released on 1997 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flight Determined Subsonic Longitudinal Stability and Control Derivatives of the F 18 High Angle of Attack Research Vehicle HARV with Thrust Vectoring written by Kenneth W. Iliff and published by . This book was released on 1997 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: