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.
Takeoff in an airplane requires airspeed. The airspeed is a measure of how fast the air is flowing over the airplane, not a measure of how fast the airplane is traveling. If the airplane is flying into a headwind, its airspeed is increased, which is why airplanes generally take off into the wind. Airspeed creates lift across the wings.