Selecting Wing Loading and Thrust to Weight Ratio for Military Jet Trainers

Author(s):  
K. Ibrahim
Keyword(s):  
Author(s):  
S Chiesa ◽  
M Di Sciuva ◽  
P Maggiore

The double-fuselage layout, sometimes proposed in the past, is considered to be an alternative (by utilizing a great number of components of an existing aircraft) to a new aircraft (with the traditional layout) of about twice the size of the existing aircraft. The development cost reduction is attractive if the technical performance of the double-fuselage is comparable with that of the hypothetical new aircraft. The first aim of the present work is to sketch a double-fuselage layout with similar values of wing loading, thrust-weight ratio and aspect ratio to the reference new aircraft of increased size. On the basis of this sketch, some other topics are discussed, such as the landing gear and tail surface configurations, ground operations, etc. Particular attention has to be paid to structural problems related to the double-fuselage layout, especially the different modes of stress in structural elements of the original aircraft.


Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 220
Author(s):  
Kunpeng Lu ◽  
Shubo Liang ◽  
Minjin Han ◽  
Chunman Wu ◽  
Jiangbo Song ◽  
...  

Flight loss has occurred in many winged insect taxa. The flightless silkmoth Bombyx mori, is domesticated from the wild silkmoth, Bombyx mandarina, which can fly. In this paper, we studied morphological characteristics attributed to flightlessness in silkmoths. Three domestic flightless B. mori strains and one B. mandarina population were used to compare morphological components of the flight apparatus, including wing characteristics (shape, forewing area, loading, and stiffness), flight muscle (weight, ratio, and microscopic detail) and body mass. Compared with B. mandarina, B. mori strains have a larger body, greater wing loading, more flexible wings and a lower flight muscle ratio. The arrangement in microscopy of dorsal longitudinal flight muscles (DLFMs) of B. mori was irregular. Comparative analysis of the sexes suggests that degeneration of flight muscles and reduction of wing mechanical properties (stiffness) are associated with silkmoth flightlessness. The findings provide important clues for further research of the molecular mechanisms of B. mori flight loss.


Author(s):  
D.M. Vanderwalker

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.


Author(s):  
W. M. Sherman ◽  
K. M. Vedula

The strength to weight ratio and oxidation resistance of NiAl make this ordered intermetallic, with some modifications, an attractive candidate to compete with many superalloys for high temperature applications. Recent studies have shown that the inherent brittleness of many polycrystalline intermetallics can be overcome by micro and macroalloying. It has also been found that the high temperature mechanical properties of NiAl can be enhanced through the addition of Nb by powder metallurgical techniques forming a dispersed second phase through interdiffusion in a polycrystalline matrix. A drop in the flow stress is observed however in a NiAl-2 at.% Nb alloy after 0.2 % strain during constant strain rate hot compression testing at 1025°C. The object of this investigation was to identify the second phase and to determine the cause of the flow stress drop.


2019 ◽  
Author(s):  
Mireia Plaza ◽  
Alejandro Cantarero ◽  
Juan Moreno

Female mass in most altricial birds reaches its maximum during breeding at egg-laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female’s capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate-guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies.


TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.


Alloy Digest ◽  
2012 ◽  
Vol 61 (5) ◽  

Abstract Tungum alloy combines an unusually high strength-to-weight ratio, with ductility, excellent corrosion resistance, and good fatigue properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming. Filing Code: Cu-806. Producer or source: Tungum Ltd.


Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.


Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  

Abstract Haynes Ti-3Al-2.5V alloy is used where the strength/weight ratio is of prime importance; the alloy is 43% lighter than 21-6-9 stainless steel. It is most often used in the form of seamless tubing for aircraft hydraulic systems. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: TI-145. Producer or source: Haynes International Inc.


Alloy Digest ◽  
1959 ◽  
Vol 8 (1) ◽  

Abstract G-E ALLOY J-1300 is a precipitation hardening iron-base alloy with an excellent strength to weight ratio. It is recommended for applications in the 1350 F. range. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SS-83. Producer or source: General Electric Company.


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