Wing design is one of the most important tasks for a designer to overcome during an aircraft design process. Therefore, a designer need to optimize so many wing geometrical parameters with the aim of obtaining an efficient wing geometry complying with requirements of the design. Taper ratio is one of these parameters, which is the ratio of root and tip chord lengths of a wing. In this study, firstly, a high aspect ratio rectangular aircraft wing was numerically investigated in terms of some aerodynamic parameters including induced drag coefficient, Oswald efficiency factor and lift coefficient together with its span-wise distribution by means of XFLR5 computational fluid dynamics program. The assessment of mesh accuracy of the program was done at the beginning of the analyses. Later on, with the aim of observing the effects of taper ratio on aircraft wing aerodynamic parameters, the revised versions of the wing, which have the taper ratios from 0.2 to 1.2 (with the increment of 0.2) were analyzed. In conclusion, depending on the analyses results, the wings having different taper ratios were compared in terms of obtained aerodynamic parameters and span-wise lift distributions. Moreover, tip vortices of each wing, together with their sizes, were obtained and also compared.

In this article, a numerical investigation was performed on a quadrotor unmanned aeroial vehicles (UAV) propeller to examine the effects of airspeed and rotational speed on thrust coefficient, which is one of the most important parameters on propeller aerodynamic performance. For that purpose, Computational Fluid Dynamics (CFD) analyses of an 11-inch propeller were carried out at different airspeeds and rotational speeds in vertical climbing flight conditions. In order to have the optimum number of mesh elements in the computational domain, mesh independence analyses were also conducted. In conclusion, the results of the analyses with the k-ω SST turbulence model were shown that increase in rotational speed was led to higher turbulent kinetic energy. Furthermore, higher rotational speeds also resulted in higher differences between numerical estimations and experimental data but were found to become more independent from airspeed.

Kanat tasarımı, tüm hava araçları için olduğu gibi, planörler için de aerodinamik performans açısından kritik öneme sahiptir. Aerodinamik olarak verimli bir planör kanadı tasarımının en önemli aşamalarından biri de uygun kanat kesit geometrisi (kanat profili) seçimidir. Bir kanat tasarımının kanat kesit geometrisi seçimi, öncelikle belirlenen gerekliliklere dayanarak karşılaştırmak üzere, farklı kanat kesit geometrilerinin aerodinamik performans analizlerini gerektirir. Bu çalışmada, dokuz farklı kanat kesit geometrisi planör aerodinamik performansı açısından karşılaştırmak üzere genel kamu lisanslı XFLR5 programı kullanılarak nümerik olarak incelenmiştir. Öncelikle karşılaştırılacak geometriler Eppler, Goettingen, NACA ve Wortmann kanat kesit geometrisi ailelerinden seçilmiştir. Karşılaştırma için programın deneysel verilerle iki boyutlu doğrulaması yapılmış ve seçilen kanat kesit geometrileri aynı koşullar altında analiz edilmiştir. Analizler 2x10 5 Reynolds sayısında ve-5 ile 20 derece arasındaki hücum açılarında gerçekleştirilmiştir. Analizlerden elde edilen sonuçlara göre kanat kesit geometrileri belirlenen gereklilikler olan kalınlık, maksimum kaldırma katsayısı ve hücum açısı, maksimum kaldırma durumundaki sürüklenme katsayısı, maksimum süzülme oranı, sıfır kaldırma durumundaki yunuslama momenti ve güç faktörüne göre karşılaştırılmıştır.

Autopilots are frequently used on UAVs with the purpose of guiding the vehicle without necessity for pilot assistance. This autonomous control performance is a considerable issue for UAVs and dramatically relates with shape of the main