X-43A Flight-Test-Determined Aerodynamic Force and Moment Characteristics at Mach 7.0

Abstract

The second flight of the Hyper-X program afforded a unique opportunity to determine the aerodynamic force and moment characteristics of an airframe-integrated scramjet-powered aircraft in hypersonic flight. These data were gathered via a repeated series of pitch, yaw, and roll doublets, frequency sweeps, and pushover-pullup maneuvers performed throughout the X-43A cowl-closed descent. Maneuvers were conducted at Mach numbers of 6.80-0.95 and at altitudes from 92,000 ft mean sea level to sea level. The dynamic pressure varied from 1300 to 400 psf with the angle of attack ranging from 0 to 14 deg. The flight-extracted aerodynamics were compared with preflight predictions based on wind-tunnel test data. The X-43A flight-derived axial force was found to be 10-15% higher than prediction. Underpredictions of similar magnitude were observed for the normal force. For Mach numbers above 4.0, the flight-derived stability and control characteristics resulted in larger-than-predicted static margins, with the largest discrepancy approximately 5 in. forward along the x-axis center of gravity at Mach 6.0. This condition would result in less static margin in pitch. The predicted lateral-directional stability and control characteristics matched well with flight data when allowance was made for the high uncertainty in angle of sideslip.

Performance Evaluation of Airframe-Integrated Aerospike Propulsion Systems in Off-Design Flight Conditions

“…For the advanced concept, the aerospike nozzle portion appears as the external nozzle. Note that in this study, the primary thrust direction is different than that of the installation used in the X-43A [27][28]. The primary thruster in this study is inclined toward the center line of the airframe axis, and therefore, the external nozzle (as an aerospike nozzle) plays a role in the compression wall for the primary engine flow.…”

Introductory Chapter: Hypersonic Vehicles - Past, Present, and Future Insights

“…The NAI's mission was to ensure the USA's aerospace leadership with an integrated, capabilityfocused, national approach that enables high-speed/hypersonic flight; safe, responsive, affordable, reliable access to and from space; and in-space operation by developing, maturing, demonstrating, and transitioning transformational aerospace technologies. In the framework of NAI, NASA performed several inflight validations of hypersonic technologies and evaluation of new concepts, such as X-43 and X-51 vehicles [11,12]. The X-43 program set out to demonstrate hydrogen-fueled scramjet operations in a fully integrated aircraft system at Mach numbers of 7 and 10.…”

Elevator Sizing, Placement, and Control-Relevant Tradeoffs for Hypersonic Vehicles

“…This paper focuses on control challenges associated with scramjet-powered hypersonic vehicles. Such vehicles are characterized by significant aerothermo-elastic-propulsion interactions and uncertainty [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] .…”