The Wright brothers had begun research into manned aircraft. Several previous attempts have failed due to the inappropriate shape of their airfoils. Furthermore, the science of aerodynamics was not developed at that time and the theoretical understanding of the mechanisms of lift and drag was weak. Researchers and flight enthusiasts who relied on theories known at the time failed because reliable models of the effects of viscosity on fluid flow were not available, the problem being quite complex and challenging any solution. But these effects are very important in determining lift, drag and stall which are important parameters for flight. Thus, the Wright brothers had no real theoretical work to guide them, and they had to rely solely on experimental work, based only on empirical guidelines. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get an original essay They knew that the lift-to-drag (L/D) ratio was the major factor in aerodynamic efficiency. So the important aspect of good aerodynamics is to produce more lift with as little drag as possible, i.e. an aircraft should be designed to have as large a lift-to-drag ratio as possible . During early experiments, the Wrights used an aspect ratio of 3 for their aerofoil. By conducting experiments in a wind tunnel, they discovered that a higher aspect ratio produces a higher lift-to-drag ratio. Immediately, they adopted another aspect ratio of 6 for their wing. In their observations, they found that the L/D ratio of the wing with an aspect ratio of 6 produced many desirable results compared to the wing with an aspect ratio of 3. This became the key to success for the Wright brothers . As a result, they also started developing airships, gliders and drones, etc., without engines. George Cayley's experiment in 1809-1810 showed that airplanes operate according to four forces, namely lift, drag, weight and thrust. Lift is the upward force that acts perpendicular to the aircraft and lift is generated due to the pressure distribution on the wing. Drag is the opposing force that resists the speed of oncoming flow. Weight is the downward force opposed to the lifting force. Thrust is the parallel force produced by an airplane. Airplanes operate according to Newton's third law: for every action, there is a reaction. When the aircraft is at a constant speed and altitude, its resultant forces are zero, which is called equilibrium in the state. Keep in mind: this is just a sample. Get a personalized article from our expert writers now. Get a Personalized Trial The key to the Wright brothers' success was the shape of the airfoil they used. They carried out numerous wind tunnel experiments on wing and airfoil shapes..