Browse Topic: Flaps
Even going as far back as bird-like dinosaurs, ornithological animals have always benefited from folding their wings during upstroke. This makes birds an interesting inspiration for the development of drones. However, determining which flapping strategy is best requires aerodynamic studies. So, a Swedish-Swiss research team has constructed a robotic wing that can flap like a bird.
The landing gear system is a major and safety critical airframe system that needs to be integrated efficiently to meet the overall aircraft program goals of minimizing the penalties of weight, cost, dispatch reliability and maintenance. As the landing gear system business develops and large-scale teaming arrangements and acquisitions become increasingly common, it may be desirable in some instances to procure an Integrated Landing Gear System. This document provides guidelines and useful references for developing an integrated landing gear system for an aircraft. The document structure is divided into four sections: Landing Gear System Configuration Requirements (Section 3) Landing Gear System Functional Requirements (Section 4) Landing Gear System Integrity Requirements (Section 5) Landing Gear System Program Requirements (Section 6) The landing gear system encompasses all landing gear structural and subsystem elements. Structural elements include shock struts, truck beams, torsion
This SAE Aerospace Information Report (AIR) relates considerations for design test procedures and test data evaluation for qualification of tire spray deflection devices.
This aerospace information report (AIR) provides historical design information for various aircraft landing gear and actuation/control systems that may be useful in the design of future systems for similar applications. It presents the basic characteristics, hardware descriptions, functional schematics, and discussions of the actuation mechanisms, controls, and alternate release systems. The report is divided into two basic sections: 1 Landing gear actuation system history from 1876 to the present. This section provides an overview and the defining examples that demonstrate the evolution of landing gear actuation systems to the present day. 2 This section of the report provides an in depth review of various aircraft. A summary table of aircraft detail contained within this section is provided in paragraph 4.1. The intent is to add new and old aircraft retraction/extension systems to this AIR as the data becomes available. NOTES 1 For some aircraft, the description is incomplete, due to
Conventional high-lift systems allow transport aircraft to safely operate at low speeds for landing and takeoff. These high-lift devices, such as Fowler flaps, are complex, heavy, and have high part counts. Fowler flap mechanisms also protrude externally under the wings, requiring external fairings, which increase cruise drag. Simple-hinged flaps are less complex, and an ideal choice for low-drag cruise efficiency. However, simple-hinged flaps require high flap deflections to achieve lift comparable to Fowler flaps. These flap deflections cause severe adverse pressure gradients, which generate flow separation that is difficult to control. In response to these challenges, NASA developed the High Efficiency Low Power (HELP) active flow control (AFC) system.
It has been established that automobile in-cabin air quality can be improved by controlling the air recirculation. It has been done since 1989 by closing and opening the flap at the right times to keep high pollution out of the cabin. This study evaluates in-cabin pollution reduction using flap open/close strategies based on real-time air quality map information received by the vehicle. Traffic pollution data was collected from vehicles with on-board air quality sensors driven for months within a city. This data was used to create high-resolution pollution maps. Using these maps, a flap open/close algorithm was designed and applied to a set of recorded trips. The amount of pollution entering the vehicle cabin was then calculated and compared, with and without flap control. Results show that the in-cabin pollution reduction achieved with flap control is significant, even with a limited amount of data collected to create the maps. It is expected that the maps will gain in predictive
This specification covers procedures and requirements for peening of metal parts with portable, bonded-shot, rotary flap assemblies in accordance with AS2592. The principles of rotary flap peening are similar to conventional shot peening, except conversion of arc height values using the magnetic test strip holder is required for intensity determination.
This document establishes the minimum requirements for ground-based aircraft deicing/anti-icing methods and procedures to ensure the safe operation of aircraft during icing conditions on the ground. This document does not specify the requirements for particular aircraft models. The application of the procedures specified in this document are intended to effectively remove and/or prevent the accumulation of frost, snow, slush, or ice contamination which can seriously affect the aerodynamic performance and/or the controllability of an aircraft. The principal method of treatment employed is the use of fluids qualified to AMS1424 (Type I fluid) and AMS1428 (Type II, III, and IV fluids). All guidelines referred to herein are applicable only in conjunction with the applicable documents. Due to aerodynamic and other concerns, the application of deicing/anti-icing fluids shall be carried out in compliance with engine and aircraft manufacturer’s recommendations.
The design of high lift device has great importance in development of transport aircraft, for both manufacturers and operators. With this motivation, a preliminary structural design of a 4-bar mechanism as an actuator of a single-slotted Fowler flap was developed. Fundamental concepts about the subject, such as overlap, gap and Fowler motion, was presented. Aiming the aerodynamic requirements, the mechanism was synthesized in order to reach three critical points: cruise, landing and take-off. For landing and take-off conditions, the loads were estimated and applied on the flaps to evaluate and to size the linkage system. The kinematics and kinetics of the movement was studied by two methods: analytical and numerical by multibody simulation. In order to refine the sizing, a finite element analysis was employed to determine the margins of safety and to drive optimization studies. Thus, with static and fatigue analysis performed and safety margins calculated, the topological optimization
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:
Formula SAE vehicles, like many other vehicles within motorsport, often employ rear mounted aerodynamic devices to improve cornering performance, these devices can however have a significant amount of aerodynamic drag. Additional speed can be gained by reducing the impact of the rear wing on the straightaways of the track through the use the aptly named Drag Reduction System (DRS), which works by reducing the angle of attack of the rear wing flap(s). A DRS can however introduce other performance losses, including the losses from having a gap between the rear wing flaps and endplate to prevent friction, the potential to stall the rear wing from improper opening angles of the flaps, and from the wake of the DRS actuator if positioned in front of the airfoils. An additional concern is the time it takes for the rear wing performance to return upon DRS deactivation, which will affect how long before corner entry the driver must disable the system. Insight into each of these problems as well
Typical automotive research in wind tunnels is conducted under idealized, stationary, low turbulence flow conditions. This does not necessarily reflect the actual situation in traffic. Thus, there is a considerable interest to simulate the actual flow conditions. Because of this, a system for the simulation of the turbulence intensity I, the integral linear scale L and the transient angle of incidence β measured in full-scale tests in the inflow of a test vehicle was developed and installed in a closed-loop, closed test section wind tunnel. The system consists of four airfoils with movable flaps and is installed in the beginning of the test section. Time-series of the flow velocity vector are measured in the empty test section to analyze the system’s envelope in terms of the turbulence intensity and the integral length scales. It is shown that the length scales in spanwise and in driving (streamwise) direction can be varied from 0.15 m to 7.9 m and from 0.15 m to 2.5 m, respectively
A previous SAE paper (2018-01-1396), (see ref 5) introduced the concept of using the frequency domain for exhaust system analysis under road excitation as a fast and efficient approach. During the intervening period further benchmarks have confirmed the validity of the approach for several exhaust systems comparing the results of simulations performed in the time domain and frequency domain for different applications. This paper will present that data and also introduce a new technique which has been developed to create, from the originating road load data (RLD), the cutting plane loads at any desired section of the exhaust system. Those loads can be used directly to determine safety factors against load capacities based, for example, on part SN curves from current or former hardware testing or even derived from statistics. The advantage lies in the early availability of virtual models in the development process, providing information about the loads acting on the system before any
Design and production of an assembly system for a major aircraft component is a complex undertaking, which demands a large-scale system view. Electroimpact has completed a turnkey assembly line for producing the wing, flap, and aileron structures for the COMAC C919 aircraft in Xi’an, China. The project scope includes assembly process design, material handling design, equipment design, manufacture, installation, and first article production support. Inputs to the assembly line are individual component parts and small subassemblies. The assembly line output is a structurally completed set of wing box, flaps, and ailerons, for delivery to the Final Assembly Line in Shanghai. There is a trend toward defining an assembly line procurement contract by production capacity, versus a list of components, which implies that an equipment supplier must become an owner of production processes. The most significant challenge faced was the amount of front end engineering work required to develop
Drag and lift are the primary aerodynamic forces experienced by automobiles. In competitive automotive racing, the design of inverted wings has been the subject of much research aimed at improving the performance of vehicles. In this direction, the aerodynamic impact of change in maximum camber of the flap element and ground effect in a double-element inverted airfoil was studied. The National Advisory Committee for Aeronautics (NACA) 4412 airfoil was taken as the constant main element. The camber of the flap element was varied from 0% to 9%, while ground clearance was varied from 0.1c to 1.0c. A two-dimensional (2D) Computational Fluid Dynamics (CFD) study was performed using the realizable k-ε turbulence model in ANSYS Fluent 18.2 to analyze the aerodynamic characteristics of the airfoil. Parameters such as drag coefficient, lift coefficient, pressure distribution, and wake flow field were investigated to present the optimum airfoil configuration for high downforce and low drag. It
This Aerospace Standard covers components of rotary flap assemblies to be used with portable equipment for peening of metal parts. The flap assemblies consist of a flap attached to a mandrel and shall be of the following sizes.
NASA’s Langley Research Center has developed aircraft flap tip modifications that reduce noise produced during approach and landing. The modifications are rigid open lattice (honeycomblike) and fin structures (closely packed columns) that delay the formation of a noise-generating vortex at the flap side edge. The designs are low-profile, with control action limited to the steady and fluctuating fields in a very small region at the flap edge. By limiting the control action to a very small region, aerodynamic characteristics of the structure remain nearly unchanged. The noise-reducing structures may be used in a variety of applications where tip vortices produce undesirable noise. These applications may include helicopter or wind turbine rotors. The technology has been validated using computational fluid dynamics analysis and wind tunnel testing. NASA is seeking partners who are interested in co-development or licensure of the technology for a variety of applications.
The automotive underbody diffuser is an expansion device which works by speeding up the air flowing underneath a vehicle. This reduces the pressure below the vehicle thereby increasing downforce. When designed properly, it can lead to a massive gain in downforce and even a reduction in drag. However, a majority of the research and development is restricted to motorsport teams and supercar manufacturers and is highly secretive. Most of the publicly available research has been done for very simple shapes (bluff bodies) to study the effects of ground clearance and rake angle. Very little research has been done for complex geometries with vanes, flaps and vortex generators. This paper aims to investigate the effects of the addition of vanes/strakes and flaps, their location as well as angle, on diffuser performance. Computational Fluid Dynamics simulations have been carried out using three dimensional, steady state RANS equations with the k-ε turbulence model on STAR CCM+ V9.06. The
This technology is a new type of design for the wing flap, aileron, or flaperon located directly behind the engine nozzle on jet aircraft. Using a concave-down curved shape for the trailing edge instead of a conventional right angle, the cross section of the flap, aileron, or flaperon directly in the jet exhaust stream is reduced, thus reducing noise.
NASA's Langley Research Center has created a novel process that significantly improves the effectiveness of high-lift devices on aircraft wings by utilizing a hybrid concept of both sweeping jet (SWJ) actuators for active flow control (AFC) and adaptive vortex generators (AVGs) for passive flow control. High-lift technology reshapes aircraft wings for more lift during takeoff and landing. Conventional high-lift devices are complex and employ a significant number of parts. In addition, these complex mechanical high-lift systems (e.g., Fowler flap mechanisms) often protrude externally under the wings, resulting in increased cruise drag. Simple hinged flaps are preferable high-lift devices for low-drag cruise performance, but they are vulnerable to flow separation at high flap deflections for both trailing edge and leading edge applications. This innovation achieves higher flap deflections without flow separation while minimizing the pneumatic power requirement of AFC.
The noise radiated inside the car cabin depends on many sources such as the embedded equipments like the Heating, Ventilation and Air Conditioning (HVAC) module. An HVAC is a compact and complex system composed of several elements: blower, flaps, thermal exchangers, ducts… Air provided by an HVAC is blown by a blower passing through different components and then distributed to car cabin areas. Interactions between airflow and the HVAC fixed components generate noises that emerge in the car cabin. CEVAS project, managed by the automotive equipment manufacturer Valeo, is aiming to develop a prediction tool which will provide HVAC noise spectrum and sound quality data. The tool is based, in particular, on aeroacoustic characterization of individual elements and associations of elements. An experimental test bench was therefore developed by the acoustic laboratory of the University of Technology of Compiègne (UTC) based on the assumption that an HVAC component is described as a 2N-port
Conventional transport aircraft wing design is driven mainly by cruise efficiency, i.e., adequate lift is generated at high speed for level flight with minimal drag. Conventional high-lift systems (leading edge slats and trailing edge flaps) were designed to augment lift and stall characteristics at the low speeds encountered during landing.
Heavy-duty gas springs are often used to replace or supplement human power when lifting or lowering heavy loads such as lids, hoods, and flaps in construction and industrial applications. In medical settings, gas springs can be found on a variety of equipment, from operating tables and hospital beds to mobility systems for people with disabilities. In all these cases, precisely controlled motion is vital for the safety and comfort of both patients and caregivers.
An aircraft trailing edge device, coupled with an aircraft wing, provides a reduction in jet-flap interaction noise while preserving the aerodynamic load capacity of the trailing edge. Embodiments of the present invention provide a trailing edge flap device that includes a center flap portion and outer edge portions, where the center flap is shorter in length in comparison to the outer edges. Additionally, the center flap is curved in the planform of the trailing edge device.
The potential of drag reduction on a generic model of a heavy vehicle using base flaps operated in combination with flow control devices is investigated experimentally. Base flaps are well known as drag reduction devices for bluff bodies and heavy road vehicles. However, for optimal performance their deflection angle should typically not exceed 12°. In this paper the primary goal is to increase the usable range of the deflection angles by applying flow control. The secondary goal is to find the most suitable method for flow control. A comparison is made between triangular vortex generators and fluidic oscillators as passive and active flow control methods, respectively. Vortex generators have the advantage of being very simple devices but produce drag. Fluidic oscillators are also quite simple devices but require additional air supply. Their advantages are that they can be activated when needed and that they do not generate additional drag. The wind tunnel model used corresponds to the
Flow control over aerodynamic shapes in order to achieve performance enhancements has been a lively research area for last two decades. Synthetic Jet Actuators (SJAs) are devices able to interact actively with the flow around their hosting structure by providing ejection and suction of fluid from the enclosed cavity containing a piezo-electric oscillating membrane through dedicated orifices. The research presented in this paper concerns the implementation of zero-net-mass-flux SJAs airflow control system on a NACA0015, low aspect ratio wing section prototype. Two arrays with each 10 custom-made SJAs, installed at 10% and 65% of the chord length, make up the actuation system. The sensing system consists of eleven acoustic pressure transducers distributed in the wing upper surface and on the flap, an accelerometer placed in proximity of the wing c.g. and a six-axis force balance for integral load measurement. A dSPACE™ hardware connected to the software environment Matlab/Simulink® and
The continuous need for improved high lift performance motivates the evaluation of innovative high lift systems. Single flap drive systems are possible solutions to implement novel functionalities for aerodynamic performance optimization. The previously mechanical coupling needs to be replaced by approved equivalent means. This directly results in high demands on control and monitoring of the multiple single drive systems in order to preserve a safe operation. In the context of the national German research project SysTAvio, strategies for a new concept of a multifunctional high lift system are investigated and presented in this paper. The conceptual system comprises four single flap surfaces, each driven by a local transmission system and powered by a local power control unit. This architecture requires an innovative control strategy for a safe operation of a single drive system as well as synchronous movement of multiple systems. Therefore different variations of peer to peer control
Two different modifications have been developed for the edges of aircraft wing flaps to reduce noise. Reactive Orthotropic Lattice Diffuser (ROLD) is a modification that consists of a honeycomb-like, interconnected structure added to the region of the flap that experiences the highest degree of sound-generating airflow instability. Flap Edge Noise Reduction Fins (FENoRFins) are modifications consisting of rigid fins on the edges of the aircraft flaps.
Following the development of new technologies in Vehicle Thermal Management aiming to both enhancing the MAC System efficiency and reducing the thermal load to be managed, a prediction tool based on the AMEsim platform was developed at Advanced PD EMEA. This tool is dedicated to predict the effect of the implementation of sensors monitoring both the relative humidity and the carbon dioxide (CO2) concentration (taking into account passengers' generated moisture and CO2). This model implemented with the usual comfort inputs (CO2 and RH acceptable ranges) considers the system variables influencing the comfort and predicts the increase of both RH and CO2 concentration in the cabin compartment in any driving cycle depending on the number of occupants. The effect of different flap control strategies based on the relative humidity and carbon dioxide sensors' inputs is compared with the extreme conditions (full Fresh Air, full Recirculation) in terms of their effect on the vehicle fuel
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