Aerodynamics, Stability and Performance Characteristics of X-Tandem Aircrafts

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Ishaan Prakash ◽  
Prithwish Mukherjee
Keyword(s):  
Performance Characteristics ◽  
The Other ◽  
Preliminary Design ◽  
Military Aircraft ◽  
Swept Wing ◽  
Combat Aircraft ◽  
Final Design ◽  
Reliable Performance ◽  
Wing Sweep ◽  
And Performance

This paper details design, analysis and validation of tandem aircraft with one wing swept forward and the other wing swept backwards. The design objective is to investigate the aerodynamic and stability characteristics of this configuration created with the motive of exploiting the manoeuvring and post stall characteristics of a forward swept wing along with the structural robustness and reliable performance of the conventional aft-swept wing. Parameters such as wing sweep, wing position, anhedral and dihedral were varied to develop a range of designs. This gave considerable information regarding the aerodynamic and stability characteristics which enabled a preliminary design of a military combat aircraft exploiting this configuration. All performance characteristics and parameters of the final design compared with current operational military aircraft give a favourable picture regarding the effectiveness of this design.

scholarly journals Effect of the wing airfoil shape on the aerodynamics and performance of a jet-trainer aircraft – An optimization approach

2021 ◽  
Vol 2120 (1) ◽  
pp. 012011
Author(s):  
K A Othman ◽  
A S Mahdi Al-Obaidi
Keyword(s):  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
The Other ◽  
Optimization Approach ◽  
Military Aircraft ◽  
Key Factors ◽  
Aircraft Performance ◽  
And Performance ◽  
Wing Airfoil ◽  
Different Altitudes

Abstract Among the key factors in developing the performance of military aircraft are its aerodynamic characteristics and performance. This research presents the effect of shape of the wing airfoil on the aerodynamic characteristics and performance of the popular jet trainer aircraft L-39C. The aerodynamic data of different airfoil shapes were used to determine the aerodynamic characteristics and performance of the L-39C for different airfoil shapes in an effort to optimize the aircrafts aerodynamic and performance. NACA 64A012 airfoil is currently used on the L-39C, however, there may exist many airfoils that may have potential to improve the aerodynamic characteristics and hence the aircraft performance. For this purpose, a group of NACA airfoils are selected, namely, NACA 4412, NACA 2415, NACA 64212 and NACA 64215. Each of these airfoil influences the aerodynamic characteristics of the aircraft and hence its performance. For each airfoil, the aircraft performance in terms of thrust required, power required, and rate of climb at different altitudes and airspeeds are calculated and analysed. The airfoil data were calculated at cruising flight at zero angle of attack to reduce the variables that can affect the calculations. The results of the calculation and analysis showed that NACA 4412 has significant results in terms of aerodynamic characteristics although in terms of aerodynamic performance, the NACA 64A012 and NACA 4412 showed lower thrust required and power required. NACA 4412 has a (C L )max of 1.67, whereas NACA 64A012 has a (C L )max of 1.336, indicating that the airfoil stalled early at higher altitudes. NACA 4412 also showed better results in terms of aerodynamic characteristics compared to the other selected airfoils although NACA 64A012 shows some variance in the results. NACA 4412 and NACA 64A212 have shown to be promising in aerodynamic characteristics and performance where one has its own benefits over the other. Although in the end, NACA 4412 may be recommended for its aerodynamic characteristics and performance.

Demands of the Tour de France: A Case Study of a World-Class Sprinter (Part I)

2020 ◽  
pp. 1-8
Author(s):  
Teun van Erp ◽  
Marcel Kittel ◽  
Robert P. Lamberts
Keyword(s):  
Intensity Distribution ◽  
Performance Characteristics ◽  
The Other ◽  
Pacing Strategy ◽  
Tour De France ◽  
Lower Load ◽  
World Class ◽  
Load Intensity ◽  
And Performance

Purpose: To describe the intensity, load, and performance characteristics of a world-class sprinter competing in the Tour de France (TdF). Method: Power output (PO) data were collected from 4 editions of the TdF (2013, 2014, 2016, and 2017) and analyzed. Load, intensity distribution in 5 PO zones, and the maximal mean PO for multiple durations were quantified. Stages were divided in accordance with the 4 different editions of the TdF, as well as the 4 different stage types, that is, flat (FLAT), semimountainous (SMT), mountain (MT), and (team) time trials. In addition, based on their location within the stage, mountain passes were further classified as BEGINNING, MIDDLE, or END of the stage. Results: No differences in load, intensity, and performance characteristics were found when the 4 editions of the TdF were compared. Time trials were associated with higher intensities but a lower load compared to the other stage types. MT showed higher load and intensity values compared to FLAT and SMT stages. FLAT stages were higher in short maximal mean PO (≤1 min), whereas MT stages showed higher longer endurance maximal mean PO values (≥20 min). In addition, mountain passes situated at the BEGINNING of the stage were completed with a higher PO, cadence, and speed compared with mountain passes situated at the END. Conclusions: A world-class sprinter sustains a higher load and spends more time in the high-intensity zones when competing in the TdF than previously reported values suggested. To finish the MT stages as efficiently as possible, sprinters adopt a reverse pacing strategy.

New Guidelines for the Preliminary Design and Performance Prediction of Axial-Flow Turbines

1987 ◽  
Vol 201 (4) ◽  
pp. 279-290 ◽  
Author(s):  
D G Wilson
Keyword(s):  
Pressure Ratio ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Preliminary Design ◽  
Outlet Angle ◽  
Blade Row ◽  
Final Design ◽  
And Performance ◽  
New Guidelines ◽  
Design Freedom

Performance charts are included that enable appropriate initial choices (that is, before final design by methods of computational fluid dynamics) to be made of reaction and flow coefficient (or blade row outlet angle) for specified stage loadings in axial-flow turbines. The radial variation in vector diagrams that leads to acceptable radial distributions of reaction at various hub-shroud diameter ratios and loadings are discussed and plotted. From these, the ranges of design freedom to choose the annulus cross-section (for example constant o.d. or i.d.) are plotted as a function of turbine pressure ratio. Also developed is a method of correlating and adding losses that should be more consistent and thermodynamically more rigorous than some previously used methods.

Acoustic and Performance Characteristics of an Ideally Twisted Rotor in Hover

2021 ◽  
Author(s):  
Nicole A. Pettingill ◽  
Nikolas S. Zawodny ◽  
Christopher Thurman ◽  
Leonard V. Lopes
Keyword(s):  
Performance Characteristics ◽  
And Performance

Performance of two combine harvester header in soybean crops

2020 ◽  
Vol 13 (2) ◽  
pp. 1
Author(s):  
E. M. Samogim ◽  
T. C. Oliveira ◽  
Z. N. Figueiredo ◽  
J. M. B. Vanini
Keyword(s):  
Experimental Design ◽  
Crop Yield ◽  
Field Performance ◽  
Travel Speed ◽  
The Other ◽  
Combine Data ◽  
Mato Grosso ◽  
Tukey Test ◽  
Combine Harvester ◽  
And Performance

The combine harvest for soybean crops market are currently available two types of combine with header or platform, one of conventional with revolving reel with metal or plastic teeth to cause the cut crop to fall into the auger header and the other called "draper" headers that use a fabric or rubber apron instead of a cross auger, there are few test about performance of this combine header for soybean in Mato Grosso State. The aim of this work was to evaluate the soybean harvesting quantitative losses and performance using two types combine header in four travel speed. The experiment was conducted during soybean crops season 2014/15, the farm Tamboril in the municipality of Pontes e Lacerda, State of Mato Grosso. The was used the experimental design of randomized blocks, evaluating four forward harvesting speeds (4 km h-1, 5 km h-1, 6 km h-1 and 7 km h-1), the natural crops losses were analyzed, loss caused by the combine harvester (combine header, internal mechanisms and total losses) and was also estimated the  field performance of each combine. Data were submitted to analysis of variance by F test and compared of the average by Tukey test at 5% probability. The results show the draper header presents a smaller amount of total loss and in most crop yield when compared with the conventional cross auger.

Growth and Performance of Agriculture Sector in India

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Naresh Singla ◽  
Mamandeep Kaur
Keyword(s):  
Growth Rate ◽  
Capital Formation ◽  
The Other ◽  
Agricultural Credit ◽  
Agricultural Growth ◽  
Indian Economy ◽  
Agriculture Sector ◽  
Food Grain ◽  
And Performance ◽  
Agricultural Labourers

The growth of agriculture and allied sectors is critical for the Indian economy as about 49 percent of the population is directly or indirectly dependent on agriculture. During the last decade and so, the agriculture sector has undergone profound changes resulting in sharp deceleration in its growth. The study has attempted to analyze growth and performance of the agriculture sector in India since 1980-81 and tries to comprehend some of the factors responsible for the deceleration in growth. The study has shown that agriculture sector has been able to show tremendous improvement in expansion of area and production of food grain and non-food grain crops. However, there are so many underlying factors responsible for slowdown of the agricultural growth. Some of the factors identified include: Increase in area under non-agriculture uses, excessive dependence on rain fed farming, increase in number of agricultural labourers, reducing size of the operation holdings, over use of agri-inputs, inequity in the distribution of agriculture credit along with sharp deceleration in public gross capital formation in agriculture etc. The study pointed in order to achieve higher growth rate, there is a need to enhance the gross capital formation in agriculture sector particularly on irrigation so that more area can be brought under assured irrigation. Bringing equity in distribution of agricultural credit coupled with judicious and need-based agricultural inputs are some of the other recommendations drawn based upon the study.

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