Initial development of the hybrid semielliptical-dolphin airfoil

Abstract

Iosif Taposu has formulated a mathematical model and generated a family of airfoils whose geometry resembles the dolphin shape. These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. On the other hand, they have not been applied to any commercial general aviation aircraft. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu?s dolphin that would have the same principal geometric characteristics. A CFD calculation model has been established and applied on NACA 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. The same CFD model has been applied on the counterpart Dolphin 2415. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1 ? 0.35 than NACA. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin?s sharp nose. A series of the Dolphin?s leading edge modifications has been investigated, gradually improving its aerodynamics. Finally, version M4, consisting of about 70% of Dolphin?s original rear domain and 30% of the new nose shape, managed to exceed the NACA?s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.

Evaluación del rendimiento energético de los cerramientos a base de bambú bajo el clima tropical de la Ciudad de Panamá

“…Otro ejemplo proviene de Fillipo Brunelleschi, quien estudió la resistencia de las cáscaras de huevo y diseñó una cúpula más delgada y liviana para la catedral de Florencia en 1436 [5]. En 1809, el arquitecto naval Sir George Cayley diseñó cascos de barcos más aerodinámicos mediante el estudio de delfines [6]. Un ejemplo más famoso ocurrió en 1948 cuando George De Mestral, un ingeniero suizo, sacó a su perro a cazar y salió de los arbustos cubierto de semillas.…”