X-34 vehicle aerodynamic characteristics

The X-34, being designed and built by the Orbital Sciences Corporation, is an unmanned suborbital vehicle designed to be used as a flying test bed to demonstrate key vehicle and operational technologies applicable to future reusable launch vehicles. The X-34 will be air-launched from an L-1011 carrier aircraft, where an onboard engine will then accelerate the vehicle to speeds above Mach 7 and altitudes to 250,000 ft. An unpowered entry will follow, including an autonomous landing. A series of wind-tunnel tests on scaled models was conducted in four facilities at the NASA Langley Research Center to determine the aerodynamic characteristics of the X-34. Analysis of these test results revealed that longitudinal trim could be achieved throughout the design trajectory. Longitudinal control effectiveness (elevon, body flap) decreased for Mach numbers greater than one and was nonlinear in the transonic regime. In addition, there was a loss in eleven effectiveness for the largest negative deflection. The rudder effectiveness (of the all-moving vertical tail) decreased for supersonic Mach numbers and with increasing angle of attack, so that at combined high supersonic Mach numbers and high angles of attack the use of reaction control jets may be required. Deployment of the landing gear reduced the eleven effectiveness by 5% and destabilized the vehicle directionally.