Speed vs flight time

As discussed, parasitic drag and other factors have an exponential effect on the speed of a sUAS versus flight time. In testing of multi-rotors and helicopters, the amount of energy required to hover, and the amount of energy required for a decent rate of forward flight are roughly the same. Rotary wing use a lot of energy to hover, and tilting forward to increase speed does not use much more energy until the aircraft reaches a critical point. In the multi-rotors this is about 80% of their maximum speed. The last 20% of the speed envelope requires that the aircraft tilt quite far forward which causes a loss in lift which is made up through an increase in power level. Each aircraft is different based upon a lot of factors. It is unlikely that a “cruise” speed has been determined for the sUAS. You can determine this fairly quickly with a few tests of your own. Fly a pattern which is larger than the copter can complete on one battery. Fly the pattern at various speeds. When the copter gets to its minimum battery level it will return to home automatically. Note that spot. Within a few flights you will determine the best speed for routine operations. With fixed wing airplanes there is not a critical speed where the energy spikes up. It increases exponentially starting at its stall speed. The best endurance for a fixed wing sUAS will always be found to be slightly above the stall speed. It is imperative to fly above the stall speed to take into account wind gusts. The higher the gusts the higher the flight speed. Fixed wing planes always have a recommended cruise speed. This accounts for the gusts. A difference of 3 knots will have a noticeable effect on the aircraft’s endurance.