Evaluation of Unsteady Loading on Store Trajectories

ABSTRACT: Clear Science Corp. proposes to develop and demonstrate accurate and computationally efficient analysis software for computing aircraft store trajectories and quantifying the risk of trajectory deviations resulting from unsteady flow in the weapons bay. The software will include physics-based, reduced-order models that predict six-degrees-of-freedom aerodynamic forces and moments acting on the store with hook ups to the Flowfield Influence Prediction Trajectory Generation Program (FLIP 4) and statistical analysis algorithms. The goal is more accurate evaluations of new aircraft/store configurations with quick turnaround times that account for all of the relevant aerodynamics including sensitivities to initial conditions (store release times) resulting from unsteadiness in the surrounding flow. These unsteady effects become more likely with gravity-dropped, lighter stores, and the likelihood of negative consequences increases in weapons that are designed for agility (neutrally stable or even unstable missile airframes). Negative consequences include collisions between the store and aircrafteither inside the bay or outside as a result of store orientation prior to firing. Targeted applications extend from initial screenings early in the weapon design and aircraft integration planning processes to final stores certification. In Phase I, the technology will be developed and validated using high-fidelity data for relevant aircraft-store configurations. BENEFIT: The commercial product to be developed is engineering software for analyzing store separation. The technology bridges the gap between comprehensive but lower-fidelity design tools that rely on simplified and/or empirical aerodynamic models and high-fidelity CFD models that are restrictive because of high computational overhead. Benefits include more reliable weapon systems with increased range, standoff distance and kill probability. The technology will reduce the risk of accidents in military aircraft, protecting crews and assets. Commercial opportunities for the store-separation analysis tool exist with military aircraft and missile manufacturers including Raytheon, Boeing, Lockheed-Martin, and Northrop Grumman. Customers also include U.S. Air Force, Navy, and Army engineers responsible for aircraft stores certification. Non-military applications range from airborne weather sensor deployment to cargo extraction on aircraft involved in search and rescue operations. Applications of the modeling technology extend from aerodynamics and store separation to structural mechanics, aero-acoustics, and guidance, navigation, and control in fixed-wing aircraft, rotorcraft, and launch vehicles.