SUMMARY / RELATED TOPICS

Camber (aerodynamics)

In aeronautics and aeronautical engineering, camber is the asymmetry between the two acting surfaces of an airfoil, with the top surface of a wing being more convex. An airfoil, not cambered is called a symmetric airfoil; the benefits of cambering were discovered and first utilized by George Cayley in the early 19th century. Camber is designed into an airfoil to maximize its lift coefficient; this minimizes the stalling speed of aircraft using the airfoil. An aircraft with cambered wings will have a lower stalling speed than an aircraft with a similar wing loading and symmetric airfoil wings. An aircraft designer may reduce the camber of the outboard section of the wings to increase the critical angle of attack at the wingtips; when the wing approaches the stall this will ensure that the wing root stalls before the tip, giving the aircraft resistance to spinning and maintaining aileron effectiveness close to the stall. Some recent designs use negative camber. One such design is called the supercritical airfoil.

It is used for near-supersonic flight and produces a higher lift-to-drag ratio at near supersonic flight than traditional airfoils. Supercritical airfoils employ a flattened upper surface cambered aft section, greater leading-edge radius as compared to traditional airfoil shapes; these changes delay the onset of wave drag. Broadly, an airfoil is said to have a positive camber if, as is the case, its upper surface is the more convex, but camber is a complex property that can be more characterized by an airfoil's camber line, the curve Z, halfway between the upper and lower surfaces, thickness function T, which describes the thickness of the airfoils at any given point. The upper and lower surfaces can be defined as follows: Z upper = Z + 1 2 T Z lower = Z − 1 2 T An airfoil where the camber line curves back up near the trailing edge is called a reflexed camber airfoil; such an airfoil is useful in certain situations, such as with tailless aircraft, because the moment about the aerodynamic center of the airfoil can be 0.

A camber line for such an airfoil can be defined as follows: Z ¯ = a An airfoil with a reflexed camber line is shown at right. The thickness distribution for a NACA 4-series airfoil was used, with a 12% thickness ratio; the equation for this thickness distribution is: T ¯ = t 0.2 Where t is the thickness ratio. Chord NACA airfoil Aerodynamic drag. Retrieved 9/7/08. Theory of Wing Sections, Ira H. Abbott and Albert E. Von Doenhoff ISBN 0-486-60586-8

Wushu at the 2016 South Asian Games

Wushu at the 2016 South Asian Games were held in Guwahati, India from 10 February – 15 February 2016. In men's Sanshou, India grabbed three gold with Uchit Sharma, Ravi Panchal, Surya Bhanu Pratap Singh emerging winners in their respective weight categories. Pakistan's Ali Haider and Maaz Khan won a gold medal defeating Shekib Haidari of Afghanistan and Mukesh Choudhary of India in the 65 kg and 70 kg categories. In the women's Sanshou event, Y. Sanathoi Devi, Anupama Devi, Puja Kadian emerged victorious grabbing all gold medals Pakistan won two gold, two silver and six bronze medals while Nepal secured one gold, 10 silver and a bronze medal. Official website

Petrinci

Petrinci is a settlement in the hills west of Sodražica in southern Slovenia. The area is part of the traditional region of Lower Carniola and is now included in the Southeast Slovenia Statistical Region. Together with the villages of Betonovo, Kračali, Janeži, Kržeti it comprises the community and Parish of Gora nad Sodražico known as Gora; the local church is dedicated to the Our Lady of the Snows. It was a medieval chapel. Petrinci on Geopedia Media related to Petrinci at Wikimedia Commons