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In order to meet the F-35 Joint Strike Fighter's strict radar cross-section and weight requirements, stealth coatings must be applied to extremely precise thickness tolerances. To meet these unprecedented tolerances, Lockheed Martin Aeronautics Company has implemented a unique Robotic Aircraft Finishing System (RAFS). This paper details the capabilities of RAFS hardware for precision coating application as compared to legacy systems. The iterative process of optimizing spray parameters and robot programs for coating thickness control on challenging F-35 geometry is also presented. Finally, results from the first coating of a production aircraft at RAFS are compared with previous hand-spray results. In keeping with Security and International Traffic in Arms Regulations, restricted information on coating materials and tolerances is not presented.

In July of 2003, the Office of the Secretary of Defense (OSD) issued a memo that made Unique Identification (UID) a mandatory Department of Defense (DoD) requirement on all solicitations issued on or after January 1, 2004. There are two aspects of the UID requirement that require attention as a company works to implement it into their processes - physical marking requirements and data management requirements. The difficulty in implementing the UID requirement grows at a seemingly exponential rate with respect to the complexity of the existing manufacturing and/or data management systems. This paper examines some of the challenges that Lockheed Martin Aeronautics has encountered as it has begun to implement the UID requirement into its production line and its data systems.

Nonlinear dynamic inversion (DI) has emerged as an area of increased application for flight control law design during recent years. It is well known that the DI control law will cause the open-loop zeros to become the poles of the closed-loop system. Hence, for a vehicle with non-minimum phase (NMP) transmission zeros, closing the loop using dynamic inversion will result in instability. In this paper, physical conditions where NMP response can occur in various air vehicle designs are first reviewed. Examples are presented for aircraft with highly flexible structure, reentry vehicle with lateral departure tendency, and hypersonic vehicle with extreme forward instantaneous center of rotation. Common design practices, including sensor blending, control mixing and vehicle configuration design changes, to eliminate the NMP response are first described.

The purpose of this technical paper and associated SAE panel discussion is to present an overview of software safety and technical integrity needs for “new” aircraft and software intensive systems development. Most of the software safety and integrity concepts presented are already proven and accepted in the commercial aircraft domain and are becoming more widely accepted for military tactical and strategic airlift aircraft. Even newer fighter/attack systems now accept the need for safety-critical functions list and more software safety focus. The focus is on effective, efficient, and essential software safety processes and modern methodologies to ensure safety-critical functions, either commanded, controlled or monitored by software, are prevented from contributing to Catastrophic and Hazardous failure conditions and resultant hazards.

This paper summarizes work done by the SAE AS-3A-2 RF/Analog Technology Task Group, which was formed to provide an applications guide for the incorporation of photonic components into aerospace RF systems. (The work is fully presented in SAE Aerospace Information Report AIR5601.) The paper presents some of the design considerations in the use of photonic technology in analog RF systems as well as some of the underlying component technology and major design choices involved.

Integration of Directed Energy Weapons (DEW) into future aircraft presents significant challenges. Principally, the need for generating and managing copious amounts of power into the Megawatt class is foreseen. Probably, the most critical and challenging area for supporting a DEW system on an aircraft is the Megawatt Class Electric Power System (MCEPS) and its associated Thermal Management Systems (TMS). MCEPS converts the aircraft fuel’s chemical energy into useable power for the load or system and the TMS disposes of the waste energy, all within the extremely challenging constraints (volume, weight, EMI, etc.) For the purposes of our studies, the MCEPS consists of the following subsystems: Engine, Power Generation, Power Conditioning, Distribution, Control, and Protection. The TMS manages Component Heat Extraction, Thermal Energy Storage, and Waste Heat disposal.

A six degree of freedom program has been developed to simulate the takeoff and landing characteristics of water based aircraft. The code integrates time dependent calculations of hydrodynamic and aerodynamic forces and moments. The aerodynamic platform for the development of the code was a C-130J fully non-linear aerodynamic model along with a fully functioning engine model. The float hydrodynamic forces and moments were calculated through the integration of the time-domain sea keeping code, AEGIR1, that uses an advanced, high-order boundary element method (BEM) to solve the three-dimensional, potential flow with free-surface waves. A feedback control system is utilized to provide control input to the aircraft (pilot model). The code simulates takeoffs and landings in varying sea states or specifically prescribed wave conditions. Any water based aircraft can be modeled using the simulation.