From this graph, Fujita then released the following descriptions for the F-Scale http://www.spc.noaa.gov/faq/tornado/f-scale.html. Over the years, the F-Scale has revealed the following weaknesses: 1  It is subjective based solely on the. 2  caused by a tornado.
9 Answers. The empty weight is the weight of the airplane including anything that is permanently attached to it and includes any un-drainable fluids. There is a maximum gross weight for takeoff and on larger aircraft there may be a maximum landing weight. The useful load is the difference between the maximum gross weight and the empty weight. To the empty weight, you have to add the fuel, oil, any other fluids, pilot and passengers, and baggage.
Modern airliners use winglets on the tips of the wings to reduce drag. The turbine engines, which are located beneath the wings, provide the thrust to overcome drag and push the airplane forward through the air. Smaller, low-speed airplanes use propellers for the propulsion system instead of turbine engines.