A full envelope database of a thrust-vectoring axisymmetric nozzle performance for the Pratt & Whitney Pitch/Yaw Balance Beam Nozzle (P/YBBN) is being developed using the F-15 Advanced Control Technology for Integrated Vehicles (ACTIVE) aircraft. At this time, flight research has been completed for steady-state pitch vector angles up to 20° at an altitude of 30,000 ft from low power settings to...

The majority of fatal aircraft accidents are associated with ‘loss-of-control’. Yet the notion of loss-of-control is not well-defined in terms suitable for rigorous control systems analysis. Loss-of-control is generally associated with flight outside of the normal flight envelope, with nonlinear influences, and with an inability of the pilot to control the aircraft. The two primary sources of n...

Modeling, simulation, and integrated guidance-control of a kinetic warhead utilizing moving-mass actuators are discussed. Moving masses can be used in any speed range both in the atmosphere as well as outside it, as long as there is a force, either aerodynamic or propulsive, acting on the vehicle. The moving-mass actuation technique offers significant advantages over conventional aerodynamic co...

This paper presents a computationally-fast inverse dynamics model based on unit quaternion orientation representation for use in the generation of unmanned aircraft trajectories when the flight envelope may include all flight path orientations, a necessary attribute for aerobatics or unmanned air-to-air combat vehicles. The model removes the inherent singularities in Euler-angle attitude repres...

Singapore grouper iridovirus (SGIV) is a major pathogen that causes heavy economic losses to the grouper aquaculture industry in China and Southeast Asian countries. In the present study, a viral envelope protein, VP39, encoded by SGIV ORF39L, was identified and characterized. SGIV ORF39L was found in all sequenced iridoviruses and is now considered to be a core gene of the family Iridoviridae....

White spot syndrome virus (WSSV) virions were purified from the tissues of infected Procambarus clarkii (crayfish) isolates. Pure WSSV preparations were subjected to Triton X-100 treatment to separate into the envelope and nucleocapsid fractions, which were subsequently separated by 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The major envelope and nucleocapsid proteins were ...

Over the past decade, NASA, under a succession of rotary-wing programs has been moving towards coupling multiple discipline analyses in a rigorous consistent manner to evaluate rotorcraft conceptual designs. Handling qualities is one of the component analyses to be included in a future NASA Multidisciplinary Analysis and Optimization framework for conceptual design of VTOL aircraft. Similarly, ...

The hovering flight of hummingbirds is one of the most energetically demanding forms of animal locomotion and is influenced by both atmospheric oxygen availability and air density. Montane Neotropical hummingbirds are expected to shift altitudinally upwards in response to climate change to track their ancestral climatic regime, which is predicted to influence their flight performance. In this s...

1 MATLAB-Based Flight-Dynamics and Flutter Modeling of a Flexible Flying-Wing Research Drone Dr. David K. Schmidt University of Colorado [email protected] Abstract A relatively low-order, linear dynamic model is developed for the longitudinal flightdynamics analysis of a flexible, flying-wing research drone, and results are compared to previously published results. The model includes the dynami...