When means thefluid is allowed to flow side-wards.To

When the plane is required to slow down in the short time, the spoiler allows to reduce the flow offluid as the theory described previously. It blocks some wind to pass above and it reduces thecoefficient then it slow down.In the most of the larger aircraft there is the wingtip device (or winglets in the other world)attached to the each ends of wings. It is used for reducing the induced drag. Induced drag is thedragging force due to the lift created by wing, the tip vortices will be generated near by the bothedges of the wing which we called wingtips (11. Winglets, 02 June 2017). The fluid where passedthrough below the wing with higher pressure will tend to move to the area where the lower pressureis. Because at the edge there is no separation between upper and lower fluid and that means thefluid is allowed to flow side-wards.To conclude that, the wing is not just a wing, it contains the tone of devices to make the flightsefficiently.14. Conclusion:After the experiment, it clarifies that the Single Down-Wing aircraft has the best performance bycomparing the Lifting force and the Lift Coefficient with the others. As the section 12 hasillustrated that the reason why the most commercial airliners are Single Down-Wing aircraftbecause they prevent the left-turn tendency better than the other kinds. Even the small light modelplane with a single Down-Wing can prevent the turning tendency of the fan.The author will want to encourage the others who want to do the flight training in the future to dothis experiment again because by doing this simple experiment helps them understand more theoriesabout aviation. The author though the importance of the temperature and air pressure. Because if thetemperature and the pressure is different, the Lift Coefficient will going to change, which meansapart of changing the another aircraft with larger wingspan or stronger engines, the pilots have to