Browse Topic: Aircraft structures
In a groundbreaking achievement, the 101st Combat Aviation Brigade, 101st Airborne Division (Air Assault) earlier this year became the first unit to successfully use the Mobile User Objective System (MUOS) function of the Army/Navy Portable Radio Communications (AN/PRC) 158 and 162 radios for conventional rotary wing operations. The trailblazing accomplishment occurred as the brigade continued its mission of providing support to ground forces, April 9, 2025.
Advanced motion control technologies are essential to modern aerospace design, supporting a wide range of safety-critical and comfort-driven applications. In aerospace, motion control components such as gas springs, actuators, and dampers are integral to nearly every commercial aircraft, rocket, satellite, and space vehicle. These critical elements support flight safety and transport functions, from the dependable deployment of landing gear and cargo doors to the smooth, ergonomic operation of seating for pilots and passengers.
Electric Vertical Take-Off and Landing (eVTOL) aircraft, conceptualized to be used as air taxis for transporting cargo or passengers, are generally lighter in weight than jet-fueled aircraft, and fly at lower altitudes than commercial aircraft. These differences render them more susceptible to turbulence, leading to the possibility of instabilities such as Dutch-roll oscillations. In traditional fixed-wing aircraft, active mechanisms used to suppress oscillations include control surfaces such as flaps, ailerons, tabs, and rudders, but eVTOL aircraft do not have the control surfaces necessary for suppressing Dutch-roll oscillations.
In a groundbreaking achievement, the 101st Combat Aviation Brigade, 101st Airborne Division (Air Assault) earlier this year became the first unit to successfully use the Mobile User Objective System (MUOS) function of the Army/Navy Portable Radio Communications (AN/PRC) 158 and 162 radios for conventional rotary wing operations. The trailblazing accomplishment occurred as the brigade continued its mission of providing support to ground forces, April 9, 2025. The MUOS function, of the AN/PRC-158 and 162 radios, operates by transmitting ultra-high frequency radio waves through a constellation of satellites to create a steady communications network. MUOS is a component of a bigger Integrated Tactical Network (ITN).
This SAE Aerospace Information Report (AIR) discusses the nature of landing gear stability, describes many common landing gear stability problems, and suggests approaches and methods for solving or avoiding them.
This SAE Aerospace Standard (AS) provides design criteria for onboard stairways intended for use by passengers aboard multi-deck transport category airplanes. It is not intended for stairways designed for use only by crewmembers, supernumeries, or maintenance personnel. Additionally, this AS does not apply to fuselage mounted or external stairways used for boarding passengers, which are covered by ARP836.
Swimming robots play a crucial role in mapping pollution, studying aquatic ecosystems, and monitoring water quality in sensitive areas such as coral reefs or lake shores. However, many devices rely on noisy propellers, which can disturb or harm wildlife. The natural clutter in these environments — including plants, animals, and debris — also poses a challenge to robotic swimmers.
High-frequency whine noise in electric vehicles (EVs) is a significant issue that impacts customer perception and alters their overall view of the vehicle. This undesirable acoustic environment arises from the interaction between motor polar resonance and the resonance of the engine mount rubber. To address this challenge, the proposal introduces an innovative approach to predicting and tuning the frequency response by precisely adjusting the shape of rubber flaps, specifically their length and width. The approach includes the cumulation of two solutions: a precise adjustment of rubber flap dimensions and the integration of ML. The ML model is trained on historical data, derived from a mixture of physical testing conducted over the years and CAE simulations, to predict the effects of different flap dimensions on frequency response, providing a data-driven basis for optimization. This predictive capability is further enhanced by a Python program that automates the optimization of flap
Performing highly representative tests of aircraft equipment is a critical feature for gaining utmost confidence on their ability to perform flawlessly in flight under the entire spectrum of operating conditions. This can also contribute to accelerate the certification process of a new equipment. A research project (E-LISA) was performed in recent years, as part of the European funded Clean Sky 2 framework, with the objective of building an innovative facility for testing an electrically actuated landing gear and brake for a small air transport. The project eventually led to the development and construction of an Iron Bird able to reproduce in a realistic and comprehensive way a full variety of landing test cases consistent with certification specifications and landing histories available in the repository of the airframer. The Iron Bird that was eventually developed is a multi-functional intelligent and easy reconfigurable facility integrating hardware and software allowing to perform
This study presents empirical modifications of Blade Element Momentum Theory (BEMT) to improve rotor performance prediction for open rotors in hovering conditions. The empirical adjustments were made to the inflow ratio, factoring in the real rotor wake area and estimated induced power losses. A comparison between experimental data and two analytical models, one using an empirical inflow formula and the other a theoretical formula (classical BEMT), was conducted for two rotors. The empirical inflow model demonstrated superior accuracy in predicting thrust and torque. These modifications are applied to the inflow ratio by accounting for the actual rotor wake area and estimated induced power losses. The findings highlight the potential for more accurate performance prediction through the integration of empirical data into theoretical frameworks.
This Aerospace Information Report (AIR) will examine considerations relative to the use of mechanical switches on aircraft landing gear, and present "lessons learned" during the period that these devices have been used.
This SAE Aerospace Recommended Practice (ARP) provides the recommended procedure for obtaining desired preloads in aircraft wheel tie bolts when mounting tires and assembling the wheel. It is generally referred to as the snug-angle bolted joint assembly procedure. It is also known as the “torque-turn” procedure in the heavy equipment ground vehicle industry.
The scope of the test method is to provide stakeholders including fluid manufacturers, airport operators, brake manufacturers, aircraft constructors, aircraft operators and airworthiness authorities with a relative assessment of the effect of deicing chemicals on carbon oxidation. This simple test is only designed to assess the relative effects of runway deicing chemicals by measuring mass change of contaminated and bare carbon samples tested under the same conditions. It is not possible to set a general acceptance threshold oxidation limit based on this test method because carbon brake stack oxidation is a function of heat sink design and the operating environment.
This SAE Aerospace Recommended Practice (ARP) establishes a procedure for disposition of aircraft wheels that have been involved in accidents/incidents or have been exposed to overheat conditions or overload conditions from loss of adjacent tire pressure (paired wheels) or wheel tie bolts.
The present document addresses gas and hydraulic fluid servicing required on commercial and military aircraft landing gears, for both single and dual chamber (also known as dual stage and two stage) shock struts. This document should be considered as landing gear industry recommended practice but in no way is meant to supersede the shock strut OEM’s published procedures.
This SAE Aerospace Recommended Practice (ARP) provides recommendations on cavity design, the installation of elastomer type spare seals in these cavities, and information surrounding elastomer material properties after contact with typical shock absorber hydraulic fluid(s) or grease. This ARP is primarily concerned with the use of spare seals on shock absorbers where only a single dynamic seal is fitted and in contact with the slider/shock absorber piston at any one time. These shock absorbers typically have a spare (dynamic) seal gland located on the outer diameter of the lower seal carrier. This spare seal gland is intended to house a spare elastomer contact seal. Split Polytetrafluoroethylene (PTFE) backup rings can also be installed in the spare seal cavity. During operation, if the fitted dynamic shock absorber standard seal begins to fail/leak, then the aircraft can be jacked up, allowing the lower gland nut of the shock absorber to be dropped down. The current used dynamic seal
From humble Chevrolet Bolts to six-figure Lucid Airs, every EV can reverse its electric motors to slow the vehicle while harvesting energy for the battery, the efficient tag-team process known as regenerative braking. Today's EVs do this so well that traditional friction brakes, which clamp onto a spinning wheel rotor or drum, can seem an afterthought. Witness Volkswagen's decision to equip its ID.4 with old-fashioned rear drum brakes, with VW claiming drums reduce EV rolling resistance and offer superior performance after long periods of disuse.
Monitoring the rotor temperature of drive machines is crucial for the safety and performance of electric vehicles. However, due to the complex operating conditions of electric vehicles, the thermal parameters of vehicular induction machines (IMs) vary significantly and are difficult to identify accurately. This article first establishes a concise but effective thermal network for IMs and analyzes the influencing factors of thermal parameters. Then, a parameter identification network (PIN) with multiple parallel branches is constructed to learn the mapping relationship between electromechanical variables and thermal parameters. Afterward, temperature datasets for network training are built through bench testing. Finally, the effectiveness of identified parameters for rotor temperature estimation application is verified, demonstrating improved interpretability, generalization ability, and accuracy compared to an end-to-end neural network.
The inductance parameter is important for the flux regulation performance of the hybrid excitation motor, and the axial structure leads to the change in the inductance parameter of the axial-radial hybrid excitation motor (ARHEM). To clarify the inductance characteristic of the ARHEM with different winding construction and the mutual coupling effect between the axial excitation and permanent magnet excitation on the inductance. Firstly, the structure of the ARHEM is presented. Secondly, the self and mutual inductance characteristics of ARHEM are analyzed using the winding function method. Then, the influence of the axial excitation structure on the armature reaction field and saliency ratio of ARHEM. On this basis, the mechanism of the mutual coupling, between the axial excitation and permanent magnet field under different excitation currents on the main air gap magnetic field, and the inductance of ARHEM with fractional slot are revealed.
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