Browse Topic: Test equipment and instrumentation
While known and largely studied, the Vortex-Ring-State (VRS) phenomenon remains the cause of numerous accidents every year and many questions are still open. In order to better understand the VRS phenomenon on different kinds of helicopters and to evaluate the effectiveness of recovery manoeuvres such as the one proposed by Capt. Vuichard, the European Union Aviation Safety Agency (EASA) launched the Helicopter Vortex-Ring-State Experimental Research project (EASA.2022.C11). Both objectives required to set-up flight test campaigns on two helicopter types, with a total of eight flights performed during the project. In addition to the description of the procedures that such flights required, the paper presents the Flight Test Instrumentation used and the analyses of the flight test data, including vibration measurements. Thus, flight conditions at which the VRS starts to develop, main parameters that influence and contribute to VRS symptoms and effects, or the effectiveness of the
Helicopter pilots are exposed to a wide range of vibration frequencies, primarily generated by engine and rotor dynamics. These vibrations, particularly within the 0.5–80 Hz range, pose significant risks to pilot health, including musculoskeletal injuries and fatigue. To mitigate these effects, vibration isolators are employed, with passive and active isolation systems offering different advantages. This study investigates the initial design and performance of a novel metal additive manufactured vibration isolator, optimized for placement under the pilot's seat in a rotorcraft simulator. The isolator was designed with key structural parameters including stiffness, coil dimensions, and material properties while maintaining a lightweight and durable form, with a primary goal of validating the additive manufacturing of a metallic isolator. Experimental corroboration was conducted by incorporating modifications to the Gannon Biomechanics Flight Simulator test stand (GBFS), comparing the
This paper will present the use of a licensed open-source software application based on commercially available off-the-shelf hardware for the control and data acquisition of aerospace system integration test rigs. System integration test rigs are complex systems requiring real-time deterministic control and high-speed data acquisition. Various aircraft flight systems and subsystems can be tested to see if they interact as they would on the aircraft without an airframe. These systems are critical to ensure interoperability during the development phase and facilitate the interchangeability of actual flight hardware, prototypes, and simulation models throughout the development cycle. Deploying open, flexible, and highly configurable real-time control and data acquisition systems ensures that development milestones will be achieved cost-effectively, whether using actual flight hardware or working with a simulation. This is because, as the prototype hardware is developed, the remaining
A cooperative flight test campaign between the US Army and NASA was performed. This test sought to characterize the acoustic emissions of a fully instrumented MD530F helicopter using a snapshot array and a phased array of microphones. The snapshot array of microphones aimed to provide even coverage across the surface of a hemisphere, providing an acoustic emission hemisphere in a single 'snapshot' of time. The phased array of microphones was designed to provide enough resolution to determine noise sources from each individual blade as well as perform source separation from main rotor and tail rotor emissions. Test conditions for the characterization effort were chosen using a traditional one-factor-at-a-time approach as well as three design of experiment approaches. Characterization conditions included constant speed level flight, descent, and ascent conditions. Transient maneuver conditions were also captured over the snapshot array. The vehicle instrumentation included measurements
AAM concepts use multiple distributed electric motors driving propellers and rotors to augment or directly generate lift and propulsive forces. Several current concepts incorporate separate drive systems for providing vertical lift, for takeoff and landing, and propulsive thrust for wing-borne cruising flight. Measurement of loads and performance on these rotating systems is very important in both the design and development stage, as well as for certification use and ultimately supporting HUMS monitoring. However, providing instrumentation in the rotating frame and extracting their associated measurements is often problematical, as it requires some means for both power and signals to bridge the rotating interface between the blade of the rotor/propeller and the fixed frame (fuselage) system. This paper describes work conducted to leverage prior CDI development of a novel optical telemetry/instrumentation system to create a prototype unit that can support ground and flight tests
For spacecraft with high power consumption, it is reasonable to build the thermal control system based on a two-phase mechanically pumped loop. The heat-controlled accumulator is a key element of the two-phase mechanically pumped loop, which allows for the control of pressure in the loop and maintains the required level of coolant boiling temperature or cavitation margin at the pump inlet. There can be two critical modes of loop operation where the ability to control pressure will be lost. The first critical mode occurs when the accumulator fills with liquid at high heat loads. The second critical mode occurs when the accumulator is at low heat loads and partial loss of coolant, for example, due to the leak caused by micrometeorite breakdown. Both modes are caused by insufficient accumulator volume or working fluid charge. To analyze the loop characteristics in critical modes, experiments were conducted on a test bench with ammonia coolant, and a mathematical simulation of a two-phase
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