China
Africa
Explore chapters and articles related to this topic
Aircraft
Published in Milica Kalić, Slavica Dožić, Danica Babić, Introduction to the Air Transport System, 2022
Milica Kalić, Slavica Dožić, Danica Babić
The landing gear has a complex structure because it must enable safe taxiing on the ground at high speeds (Figure 2.8). It has an extremely strong mechanism with systems that can withstand the ground impact of an aircraft weighing over 100 tons (the maximum landing mass of the aircraft A380 is close to 400 t) at a speed of over 200 km/h. The landing gear consists of several components such as hydraulics systems (extraction and retraction mechanism), air/oil shock struts as an energy absorption component, brakes, wheels, and tyres. The landing gear must absorb the landing shock, which means absorption of the kinetic energy due to the aircraft mass and velocity of descent at impact. In order to keep the pistons and wheels aligned, most shock struts have torque links or torque arms hinged to the fixed upper and the lower cylinder (piston). This does not allow rotation of the shock absorber piston.
An automatic engine-out recovery system
Published in Hans M. Soekkha, Aviation Safety, 2020
In any engine-out take-off it is essential that the aircraft take off cleanly without allowing the wheels of the undercarriage to touch the ground again. Such contact would occur with a crabbing motion (relative to the runway surface) as a consequence of the sideslip which has developed. Crabbing motion would impose on the landing gear an increased load which could result in the gear’s collapsing, leading to damage to the aircraft. It is advisable to retract the landing gear as soon as possible after continuing a take-off with engine failure, if possible at a height of 10-15ft (3-5m) above the ground, when the possibility of further contact between the aircraft wheels and the ground can be excluded. Retracting the landing gear usually reduces the aerodynamic drag1 effectively increasing thereby the thrust margin of the aircraft.
Drag force and drag coefficient
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
Landing gear (or undercarriage) is the structure (usually struts and wheels) that supports the aircraft weight and facilitates its motion along the surface of the runway when the aircraft is not airborne. Landing gear usually includes wheels and is equipped with shock absorbers for solid ground, but some aircraft are equipped with skis for snow or floats for water, and/or skids. To decrease drag in flight, some landing gears are retracted into the wings and/or fuselage with wheels or concealed behind doors; this is called retractable gear. In the case of retracted landing gear, the aircraft clean CDo is not affected by the landing gear.
Design optimisation and experimental verification of a UAV’s landing gear buffer
Published in International Journal of Crashworthiness, 2023
Unmanned aerial vehicle (UAV) technology has advanced significantly since its creation, with both military and commercial applications. UAVs can offer customisation in terms of design, size, range, weight, engine type, and the carrying of communication equipment and sensors, and they have outstanding application prospects due to the wide variety of UAVs, simple deployment, flexible applications, and scalability [1]. The optimised design of UAV landing gear faces significant challenges as a result of these requirements. The landing gear is an essential component to ensure adequate bearing capacity and stability in the absorption of takeoff and, landing impact energy. The landing gear needs to be made as small and light as feasible, with enough endurance and payload capacity. The design of the landing gear particularly focuses a great deal on the cushioning system. A better cushioning system can lessen landing loads, absorb enough impact energy, and lighten the weight of the aircraft construction [2]. Improving and optimising the buffer system performance is always the core technology and research focus [3,4]. The buffer system performance depends mainly on the design of the buffer, and the proper configuration of the buffer parameters has a decisive influence on the performance [5].
Shock and harmonic response analysis of UAV nose landing gear system with air damper
Published in Cogent Engineering, 2021
Lovely Son, Muhammad Surya, Mulyadi Bur, Ubaidillah Ubaidillah, Radon Dhelika
The maximum landing gear displacement during landing is another factor that should be considered for designing the landing gear system. The maximum displacement response is limited by the available space in the UAV fuselage. Generally, the large landing gear stiffness can reduce the maximum landing gear displacement; however, it has a negative effect in increasing the maximum acceleration response of the UAV body during landing.