Browse Topic: Rotary-wing aircraft

Items (672)
A tested method of data presentation and use is described herein. The method shown is a useful guide, to be used with care and to be improved with use.
S-12 Powered Lift Propulsion Committee
Engines subject to dust, industrial pollution, saltwater contamination or other chemically laden atmosphere (including pesticides and herbicides) lose performance due to deposits of contaminants on surfaces in the aidgas flow path. Engine wash and engine rinse procedures are utilized to restore turbine engine performance. These procedures are generated by the engine manufacturer and are included in the Engine Maintenance/Service Manuals. For most turbine engines these procedures are similar in concept and practice; however, application details, choice of solvents and many other service features can vary from engine manufacturer to engine manufacturer and may even vary within the range of engine models produced by any manufacturer. The intent of this SAE Aerospace Information Report (AIR) is to outline the general nature, considerations, and background of engine wash and engine rinse and is directed towards the needs of the entry level engineer, service engineer, and those involved in
S-12 Powered Lift Propulsion Committee
Airbus Marignane, France laurence.petiard@airbus.com
The purpose of this SAE Aerospace Information Report (AIR) is to provide rotorcraft and engine designers with a better understanding of turboshaft engine idle power characteristics and objectives to be considered in the design and integration process. For the purpose of this document, idle is the lowest suitable steady-state power setting, most commonly corresponding to a gas generator speed setting or range. In general, a lower engine idle setting is desired by the airframer to reduce noise, fuel consumption, and main rotor downwash when on the ground and to reduce the size requirement of a rotor brake system. In contrast, the engine manufacturer generally prefers a higher engine idle setting, as operation further away from the engine design speed involves more challenges in operability and mechanical design. A variety of rotorcraft and engine factors are described for consideration. Some typical engine power and torque trends are presented for illustrative purposes. The information
S-12 Powered Lift Propulsion Committee
There are examples in aerodynamics that take advantage of electric-to-aerodynamic analogies, like the law of Biot–Savart, which is used in aerodynamic theory to calculate the velocity induced by a vortex line. This article introduces an electric-to-aerodynamic analogy that models the lift, drag, and thrust of an airplane, a helicopter, a propeller, and a flapping bird. This model is intended to complement the recently published aerodynamic equation of state for lift, drag, and thrust of an engineered or a biological flyer by means of an analogy between this equation and Ohm’s law. This model, as well as the aerodynamic equation of state, are both intended to include the familiar and time-proven parameters of pressure, work, and energy, analytical tools that are ubiquitous in all fields of science but absent in an aerodynamicists’ day-to-day tasks. Illustrated by various examples, this modeling approach, as treated in this article, is limited to subsonic flight.
Burgers, Phillip
This article introduces an advanced state-of-charge (SOC) estimation method customized for 28 V LiFePO4 (LFP) helicopter batteries. The battery usage profile is characterized by four consecutive current pulses, each corresponding to distinct operational phases on the helicopter: instrument check, key-on, recharge, and emergency power output stages. To establish a precise battery model for LFP cells, the parameters of a second-order equivalent-circuit model are identified as a function of C-rate, SOC, and temperature. Furthermore, the observability of the battery model is assessed using extended Lie derivatives. The signal-to-noise ratio (SNR) of the open-circuit voltage (OCV)–SOC relation is analyzed and employed to evaluate the estimator’s resilience against OCV flatness. The extended Kalman filter (EKF) and the unscented Kalman filter (UKF) are utilized for SOC estimation. The results emphasize the significance of meticulously choosing process and sensor noise covariance matrices to
Gao, YizhaoNguyen, TrungOnori, Simona
This SAE Aerospace Recommended Practice (ARP) is an industrial collaboration with regulatory bodies like the European Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA) to determine the worst-case credible thermal runaway (TR) condition (energy released and maximum temperature) for the design of an aviation large propulsion battery system to quantitatively verify TR in lieu of battery level RTCA DO-311A testing with protections disabled. The ARP considers the three stages of TR within a cell and defines the two critical temperatures for a specific cell design. These temperatures are key to understanding the layers of monitoring necessary to determine the severity of a TR event. Different trigger methods can be used to quantify the heating characteristics and resultant energy profile releases as a function of time. Results show three general phases of the event critical temperature (see 1.5) corresponding with the reaction between the cell’s solid electrolyte
AE-7D Aircraft Energy Storage and Charging Committee
This SAE Aerospace Recommended Practice (ARP) identifies and defines methods of compliance with power available and inlet distortion requirements for rotorcraft with inlet barrier filter (IBF) installations. The material developed herein is intended to provide industry-recommended methods of compliance with civil airworthiness regulations. It is intended to serve as a basis for new or revised FAA advisory material describing acceptable methods for determining power assurance, establishing power available, and for substantiating acceptable engine inlet distortion for IBF installations. The ARP does not address other types of inlet protection systems such as inertial separator, electrostatic precipitators, or foreign object debris (FOD) screens. It is agreed to treat dust, ice, salt, water, and snow as contaminants to the IBF for the purpose of establishing power available and assessing inlet distortion, but any other effects of ice and snow on inlet airworthiness are outside the scope
S-12 Powered Lift Propulsion Committee
The purpose of this SAE Aerospace Information Report (AIR) is to disseminate qualitative information regarding foreign object debris (FOD) damage to the gas path of rotorcraft gas turbine engines and to discuss methods of FOD prevention. Although turbine-powered fixed-wing aircraft are also subject to FOD, the unique ability of the rotorcraft to hover above, takeoff from, and land on unprepared surfaces creates a special need for a separate treatment of this subject.
S-12 Powered Lift Propulsion Committee
This paper focuses on the design of the thermoelectric ice protection system (IPS) for the engine air intake of the Next Generation Civil Tiltrotor (NGCTR), a demonstrator under development in Leonardo Helicopters. A specific IPS design strategy for the novel intake configuration is proposed. The main constraint which driven the design strategy is a maximum power of 10.6 kW available for the full intake IPS system. The IPS was designed for safe aircraft operations within the Appendix-C icing envelope. The numerical approach adopted to perform the design and the resulting IPS concept are presented. Calculations of the required IPS heat fluxes revealed that maintaining running wet conditions on the entire intake surface is not feasible due to the limitation to the maximum IPS power demand. Therefore, a de-icing IPS design strategy is proposed. The anti-icing mode is adopted only on the lip region to avoid formation of ice caps whereas de-icing zones are defined within the intake duct
Tormen, DamianoZanon, AlessandroDe Gennaro, Michele
Ice accretion on helicopter rotor blades when flying through supercooled droplet clouds can severely affect aerodynamic properties and pose a significant threat to flight safety. In the design phase, manufacturers commonly use 2D or quasi-3D simulations to predict potential ice accretion, which are more economical than fully 3D approaches. However, these methods frequently encounter accuracy issues when predicting the precise amount of ice accretion because the 3D flow field significantly influences droplet trajectories and, as a result, impingement and accreted mass. For this study the Eulerian particle solver of the icing software DICEPS was upgraded from 2D to 3D using second-order schemes, ensuring numerical stability on unstructured mesh configurations. Validation of the 3D modifications was performed by comparing numerical results of the collection efficiency on a sphere with experimental data. Droplet trajectory calculations were then conducted on a NACA0012 rotor in hover
Buchen, PhilippSotomayor-Zakharov, DenisKnop, Inken
This paper is focused on the numerical analysis of the impingement and water catch rate of snow particles on the engine air intake of the Next Generation Civil Tilt Rotor (NGCTR). This NGCTR is developed by Leonardo Helicopters. The collection efficiency and water catch rate for the intake geometry are obtained for the test cases that have been defined for the relevant snow conditions. These conditions are related to the flight envelope of the NGCTR, existing EASA/FAA certification specifications, and the snow characterization. The analyses have been performed for the baseline air intake geometry. A range of particle diameters has been simulated with a particle density equal to the density of ice and with a particle drag relation that disregards the particle shape. Based on the results for the water catch rate on the basic nacelle configuration in snow conditions it is concluded that the ‘cheeks’ of the duct are more susceptible to impingement of larger snow crystals (>75 μm), whereas
Kool, NinaVan der Weide, EdwinSpek, Ferdinandvan der Ven, Harmenvan 't Hoff, Stefan
The simulation of natural-like snow conditions in a controlled environment such as an Icing Wind Tunnel (IWT) is a key component for safe, efficient and cost-effective design and certification of future aircraft and rotorcraft. Current capabilities do not sufficiently match the properties of natural snow, especially in terms of size and morphology. Within the Horizon 2020 project ICE GENESIS, a new technology has been developed aiming to better recreate natural snowflakes. The focus of the newly developed system was the generation of falling snow in a temperature range of +1°C to -4°C. Ground measurements and flight test campaigns have been performed to better characterize these conditions and provide requirements for wind tunnel facilities. The calibration results of the new snow generation system as well as snow accretion data on a NACA0012 test article with a chord length of 0.377 m are presented. The influence of different snow conditions on the accretion rate and the overall shape
Breitfuß, WolfgangFerschitz, HermannSchwarzenboeck, AlfonsHeller, RomyPervier, HugoDupuy, RegisJaffeux, LouisBerne, Alexis
Small uncrewed aircraft systems (sUAS) growth continues for recreational and commercial applications. By 2025, the Federal Aviation Administration (FAA) predicts the sUAS fleet to number nearly 2.4 million units. As sUAS operations expand within the National Airspace System (NAS), so too does the probability of near midair collisions (NMACs) between sUAS and aircraft. Currently, the primary means of recognizing sUAS NMACs rely on pilots to visually spot and evade conflicting sUAS. Pilots may report such encounters to the FAA as UAS Sighting Reports. Sighting reports are of limited value as they are highly subjective and dependent on the pilot to accurately estimate range and altitude information. Moreover, they do not account for NMACs that an aircrew member does not spot. The purpose of this study was to examine objective sUAS and aircraft telemetry data collected using a DJI Aeroscope sensor and Automatic Dependent Surveillance-Broadcast (ADS-B)/Mode S messages throughout 36 months
Wallace, Ryan J.Winter, Scott R.Rice, StephenKovar, David C.Lee, Sang-A
This SAE Aerospace Information Report (AIR) defines the helicopter bleed air requirements which may be obtained through compressor extraction and is intended as a guide to engine designers.
S-12 Powered Lift Propulsion Committee
In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics
Burgers, Phillip
This SAE Aerospace Recommended Practice (ARP) contains the general requirements and test procedures for Dual Mode (NVIS Friendly visible and Covert) exterior lighting for most rotorcraft and fixed wing aircraft and could be applicable to ground vehicles that desire a Dual Mode lighting system.
A-20B Exterior Lighting Committee
This SAE Aerospace Information Report (AIR) describes the different aspects of corrosion on helicopter powerplants, on the components that are affected, and the subsequent consequences on the helicopter, engine durability, performance, and dependability. Guidelines that minimize corrosion during the design stage and during service operation are also discussed.
S-12 Powered Lift Propulsion Committee
Bell Amarillo, TX 817-280-1949
The primary focus of this document is to provide information on the impacts hard landings and abnormal load conditions on landing gear and related systems. However, because hard landings potentially affect the entire aircraft, this document also includes information for non-landing gear areas. The document may be considered to be applicable to all types of aircraft. This document does NOT provide recommended practices for hard landing inspections, nor does it provide recommendations on the disposition of damaged equipment. Refer to ARP4915 and ARP5600 for information on dispositions relating to landing gear components or wheels involved in accidents/incidents.
A-5B Gears, Struts and Couplings Committee
This document describes a method to calculate noise level adjustments at locations behind an airplane (described by an angular offset or directivity) at the start of takeoff roll (SOTR). This method is derived from empirical data from jet aircraft (circa 2004), most of which are configured with wing-mounted engines with high by-pass ratios (Lau, et al., 2012). Methods are also described which apply to modern turboprop aricraft. Calculations of other propagation-related adjustments required for aircraft noise prediction models are described in AIR1845A, ARP5534, ARP866A, and AIR5662.
A-21 Aircraft Noise Measurement Aviation Emission Modeling
There’s no question that significant amounts of power are needed for electric-powered vertical takeoff and landing (eVTOL) aircraft to become airborne and maintain flight. But designers of rotorcraft and personal air vehicles (PAVs) have many questions about what kinds of electrical interconnects can handle the required voltages and kW peak output for electric propulsion motors, inverters, controllers, batteries, infotainment, and sensors. To make eVTOL a reality, designers must identify the proper connectivity solution and implement a “follow-the-wire” design approach to overcome the following challenges:
There's no question that significant amounts of power are needed for electric-powered vertical takeoff and landing (eVTOL) aircraft to become airborne and maintain flight. But designers of rotorcraft and personal air vehicles (PAVs) have many questions about what kinds of electrical interconnects can handle the required voltages and kW peak output for electric propulsion motors, inverters, controllers, batteries, infotainment, and sensors. To make eVTOL a reality, designers must identify the proper connectivity solution and implement a “follow-the-wire” design approach to overcome the following challenges:
This document includes recommendations of installations of adequate landing and taxiing lighting systems in aircraft of the following categories: a Single engine personal and/or liaison type b Light twin engine c Large multiengine propeller d Large multiengine turbojet e Military high performance fighter and attack f Helicopter which are subject to the following CFR Parts certification: Part 23 – Airworthiness Standards: Normal, Utility, Acrobatic and Commuter Aircrafts Part 25 – Airworthiness Standards: Transport Category Aircrafts Part 27 – Airworthiness Standards: Normal Category Rotorcraft Part 29 – Airworthiness Standards: Transport Category Rotorcraft
A-20B Exterior Lighting Committee
Create and publish a list of terms relevant to electrified propulsion aircraft with summary text descriptions. The terms and descriptions will not provide full explanations, diagrams, and other detailed technical descriptions. These deeper descriptions will be addressed in other documents. This document defines the relevant terms and abbreviations related to the design, development, and use of electrified propulsion in aircraft. This definition is provided to enable a consistent use of technical language throughout the standards developed by the E-40 committee.
E-40 Electrified Propulsion Committee
Current trends in the rotorcraft market favor aircraft with higher power electronic equipment, smaller, more efficient propulsion systems, and higher flight speeds. The power consumers are putting a greater tax on electrical systems, but also pushing already stressed thermal management systems. The first goal of this brief study aims to calculate and identify major trending of drag and power consumption imposed by equipment cooling on high-speed rotorcraft. Major contributors to these quantities include total heat load, equipment qualification temperature, flow passage sizing and inlet/exhaust orientation to free stream. During preliminary aircraft design, these factors are sometimes disregarded or deprioritized, as they may lead to weight increases, design challenges, and schedule changes. However, ignoring them tends to yield a cascade of other issues later in the design process, often in the way to airframe and electrical system, along with a decrement in overall aircraft
Valentine, Taylor
Slowed rotors – traditionally associated with autogyros and gyroplanes – have long been recognized as one potential solution for high-speed helicopters (200-300 knots). During the 1950s–70s, there were several significant programs that led to the development of high-speed helicopters with thrust and lift compounding. The key technology barriers common to all were extremely high fuel consumption due to high advancing side drag and large reverse flow, complexities associated with RPM reduction, large blade motions during RPM reduction, and unexplained but catastrophic aeroelastic instabilities of rigid rotors (Cheyenne). None of these helicopters entered regular production.
The intent of this SAE Aerospace Information Report (AIR) is to document the design requirements and approaches for the crashworthy design of aircraft landing gear. This document covers the field of commercial and military airplanes and helicopters. This summary of crashworthy landing gear design requirements and approaches may be used as a reference for future aircraft.
A-5B Gears, Struts and Couplings Committee
In August 2011, a US CH-47 Chinook helicopter began its descent in a remote corner of Afghanistan to insert elite Special Forces soldiers at an important objective. Unseen by the aircrew or US reconnaissance drones, a Taliban operative fired a Rocket Propelled Grenade (RPG) at the landing Chinook aircraft, causing it to lose control and crash, killing all 38 service members on board.
This document covers recommendations for the application of existing qualified and approved in-service fixed wing aircraft tires, wheels and brakes to military and commercial rotorcraft. NOTE: This document does not address the use of radial tires due to insufficient data to support their approved use on rotorcraft, see paragraph 4.3.14 for specific impact on ground resonance.
A-5 Aerospace Landing Gear Systems Committee
This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics. This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service. The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.
S-12 Powered Lift Propulsion Committee
The Safety Assessment Process, defined by SAE ARP4761 and associated regulatory guidance, is described in the context of conventional, crewed civil aircraft. While this material has been used for decades to evaluate airplanes and rotorcraft, the evolution of technology challenges it. As new entrants venture into aviation, they bring perspectives, which may not clearly align to those conventional concepts. For those skilled in the art of aviation safety assessment, the approach to new technologies might appear straight forward. Such an individual might easily perceive the accommodations for unconventional applications. Once accommodations are made, and failure conditions are established and classified to those new architectures, the rest of the process is somewhat mechanical -they flow out of these conditions. However, the context of their experience betrays the reality of the process description in the ARP and guidance. Such accommodations are not discussed in them, and the process
Voros, Robert
This Glossary is designed to serve persons who need to know the accepted meanings, within specific contexts, of the terminology used in reports, articles, regulations, and other materials dealing with aviation safety -- with particular reference to terms specific to human factors in aviation safety. It is assumed that some users of the Glossary will be familiar with the nomenclature of aviation, but will need information on the language of human factors in engineering as they apply to aviation safety. Others (for example, engineers and psychologists) will have fairly extensive knowledge of the terminology of their own and related disciplines, but will need authoritative definitions of technical terms specific to aviation. Within the foregoing general framework, the following guidelines for the inclusion of terms to be defined have been observed:
G-10EAB Executive Advisory Group
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