Topic
Landing gear
About: Landing gear is a research topic. Over the lifetime, 3403 publications have been published within this topic receiving 25370 citations. The topic is also known as: landing gear & gear.
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11 Jan 1999
TL;DR: It is shown that the aircraft impact and vibration isolation properties of the dynamic response of motions can be improved and the highly nonlinear aircraft dynamics coupled with varying landing and runway conditions are handled with the proposed fuzzy controller.
Abstract: With respect to fatige life of both the landing gear and airframe and passenger comfort the good landing impact and taxi performances are becoming more important due to the increasing in life time and in taxi distancea of aircraft. This paper presents a semi-active landing gear system controlled with fuzzy logic. It ie shown that the aircraft impact and vibration isolation properties aa well e.a the dynamic response of motions can be aigoiflcantly improved. The highly nonlinear aircraft dynamics coupled with varying landing and runway conditions are handled web with the proposed fuzzy controller.
24 citations
Patent•
04 Jun 1973
TL;DR: In this article, the main landing gear is designed to provide abnormally high ground clearance at touchdown, for minimum ground effect and maximum nose-down angle, and then to slowly sink to normal ground clearance during the landing roll.
Abstract: An airplane main landing gear is designed to provide abnormally high ground clearance at touchdown, for minimum ground effect and maximum nose-down angle, and then to slowly sink to normal ground clearance during the landing roll. This gear may be contracted to lower or ''''kneel'''' the airplane. In addition, differential lengthening of left and right gears is provided to permit the airplane to land in a banked attitude for crosswind landings, thereby obviating the necessity to fully straighten-out the airplane before touchdown during such operations. The latter feature also provides a crosswind gear which is operationally less complicated than conventional crosswind gears which necessitate turning/steering all gears or wheels.
24 citations
07 Jun 2010
TL;DR: Acoustic and resistance measurements were performed in NLR's Small Anechoic Wind Tunnel on a large number of meshes intended for landing gear noise reduction, finding that the meshes yield a drastic broadband noise reduction for a wide range of mesh materials and mesh shapes.
Abstract: Acoustic and resistance measurements were performed in NLR's Small Anechoic Wind Tunnel on a large number of meshes intended for landing gear noise reduction. The meshes were tested on generic bluff bodies which simulated single and combined landing gear struts. An out-of-flow microphone array was used to localize and quantify the noise sources on the model. It is found that the meshes yield a drastic broadband noise reduction for a wide range of mesh materials and mesh shapes. The noise reduction occurs for all tested angles of attack and for all tested models. For the combined bodies it is found to be sufficient to treat only the upstream component with a mesh.
24 citations
TL;DR: A new robust controller based on model reference sliding mode control and adaptive hybrid control is proposed to improve the efficiency of absorbing landing impact energy, not only considering the variables of aircraft weight and sink speed but also managing uncertainties, such as ambient temperature and passive damping coefficient.
Abstract: A landing gear of an aircraft is required to function at touchdown in different landing scenarios with parametric uncertainties. A typical passive damper in a landing gear has limited performance in differing landing scenarios, which can be overcome with magnetorheological (MR) dampers. An MR damper is a semi-active system that can adjust damping force by changing the amount of electric current applied to it. This paper proposes a new robust controller based on model reference sliding mode control and adaptive hybrid control to improve the efficiency of absorbing landing impact energy, not only considering the variables of aircraft weight and sink speed but also managing uncertainties, such as ambient temperature and passive damping coefficient. To verify the effectiveness of the proposed controller, comparative numerical simulations were performed with a passive damper, a skyhook controller, and the proposed controller under various landing scenarios. The simulation results show that the proposed controller improves the total energy absorber efficiency by up to 10% higher than that of the skyhook controller. In addition, the proposed controller is demonstrated to have better adaptability and robustness than the other control algorithms in the differing landing scenarios and parametric uncertainties.
24 citations
Patent•
16 Mar 1979
TL;DR: In this paper, a gas hydraulic shock absorbing landing gear strut with a pneumatic spring in combination with a hydraulic fluid controlling orifice for touchdown and automatic means for changing mode after touchdown to impart new hydraulic spring characteristics and to provide duo paths for controlling hydraulic fluid flow.
Abstract: A duo mode gas hydraulic shock absorbing landing gear strut with a pneumatic spring in combination with a hydraulic fluid controlling orifice for touchdown and automatic means for changing mode after touchdown to impart new pneumatic spring characteristics and to provide duo paths for controlling hydraulic fluid flow.
24 citations