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UAS Airframe Design
Published in R. Kurt Barnhart, Douglas M. Marshall, Eric J. Shappee, Introduction to Unmanned Aircraft Systems, 2021
Michael T. Most, Michael Stroup
In a conventionally designed aircraft, the vertical stabilizer is the primary source of directional control and stability. (Although a wing, especially one that is swept, will contribute to static directional stability, any effect is relatively slight.) Should the aircraft yaw, or sideslip, the change in angle of attack of the vertical stabilizer causes a side force (change in pressure differential acting on the major surfaces of the vertical stabilizer) to yaw the aircraft about the CG in a restoring moment that will turn the nose of the aircraft into the relative wind. The size of the vertical stabilizer and the arm (distance between the stabilizer and the CG, or x-axis) will determine the effectiveness of the stabilizer in creating a restoring force following any displacement of the nose in yaw.
UAS Airframe and Powerplant Design
Published in Douglas M. Marshall, R. Kurt Barnhart, Eric Shappee, Michael Most, Introduction to Unmanned Aircraft Systems, 2016
In a conventionally designed aircraft, the vertical stabilizer is the primary source of directional control and stability. (Although a wing, especially one that is swept, will contribute to static directional stability, any effect is relatively slight.) Should the aircraft yaw, or sideslip, the change in angle of attack of the vertical stabilizer causes a side force (change in pressure differential acting on the major surfaces of the vertical stabilizer) to yaw the aircraft about the center of gravity in a restoring moment that will turn the nose of the aircraft into the relative wind. The size of the vertical stabilizer and the arm (distance between the stabilizer and the cg, or x-axis) will determine the effectiveness of the stabilizer in creating a restoring force following any displacement of the nose in yaw.
Influence of the interlayer film thickness on the mechanical performance of AA2024-T3/CF-PPS hybrid joints produced by friction spot joining
Published in Welding International, 2018
Natália M. André, Seyed M. Goushegir, Jorge F. dos Santos, Leonardo B. Canto, Sergio T. Amancio-Filho
Recently, the development of lightweight hybrid structures has become the focus of industries in the transport sector. In the aeronautical industry, for example, the structure of the Boeing 787 consists, to more than 50 wt%, of advanced polymer composites; a 20% decrease in the total weight of the aircraft compared to the structure fabricated conventionally in aluminium [3]. In the last 30 years, Airbus has also been investigating the use of carbon fibre-reinforced polymers in its aircraft. Applications have been developed for components such as variable geometry wings and the tail fin of the A310, the tailplane of the A320, the vertical stabilizer of the A340-600, the central box of the wing of the A380, as well as parts of the wings of the Falcon 10, ATR 72 and A400 M [4]. Moreover, the recent launch of the A350 XWB created a new standard in this class of aircraft from Airbus. This model gave a 25% reduction in fuel consumption owing to the use of 53% of polymer composites in its structure [4]. In the Brazilian scenario, Embraer has also invested in carbon fibre-reinforced polymers. The recent launch of the military cargo transport aircraft – the KC-390 – demonstrated for the first time on a national scale the use of polymer composites in lightweight solutions for ballistic protection [5]. In addition, in the automotive industry, a new generation of electric and hybrid cars has been developed by BMW (e.g. i3 and i8). By replacing the traditionally used steel with carbon fibre-reinforced polymers and aluminium, the engineers at BMW were able to make dramatic reductions in the weight of the vehicles. Besides reducing the weight of the vehicle itself, the replacement structure gives a 50% saving of energy and 70% saving of water in the manufacturing process [6].
Tailoring specific properties of polymer-based composites by using graphene and its associated compounds
Published in International Journal of Smart and Nano Materials, 2020
Pui-yan Hung, Kin Tak Lau, Qiaoshi Guo, Baohua Jia, Bronwyn Fox
Recently, more research interest has focused on developing graphene reinforced polymer-based composites for aircraft and automotive engineering applications. In the aircraft engineering industry, the use of advanced composites for primary and secondary structural components has increased substantially since the past two decades. Using composites could greatly reduce the gross weight of airplanes, and thus the fuel consumption. It also helps reduce the production of greenhouse gases, which are the major sources to cause the global climate change. Glass fiber reinforced polymer (GFRP) and CFRP are two common types of composites for aircraft structures. The strength of GFRP is relatively lower than CFRP. Therefore, they are normally used for the secondary structures, such as leading edges and vertical stabilizer. Recently, CFRP has been used to replace aluminum for fuselage and wing structures for Boeing 787, Airbus A350, and A380. Using advanced composites for aircraft structures needs to fulfill requirements that may not be strictly necessary for domestic products used at the ground attitude. According to the International Standard Atmosphere (ISA), the ambient temperature, pressure, and air density at the flying attitude (11,000 km) are −56.5°C, 22KPa, and 0.365 kg/m3 respectively. At ground level, they are 15°C, 1013 KPa, and 1.225 kg/m3 respectively. Therefore, the design of aircraft structures must be able to withstand the temperature and pressure variations during in flight condition. Material fatigue is another issue that impacts the structural integrity of the structures. It is relatively difficult for composite structures to have structural repair as compared with other metallic structures, like aluminum alloys. Bonding of composite patches on a damaged area requires special techniques and a perfect environmental control to ensure appropriate pressure and temperature applied during the curing process.