Flygteknik
Konceptstudie av ett obemannat flygplan
Unmanned aerial vehicles (UAV?s) are nowadays greatly appreciated. The advantage over manned airplanes are great since UAV?s can be much smaller and therefore lighter. The goal of this project is to evaluate the performance of an environmentally friendly UAV using only lithium-ion batteries. This in doing monitoring of agriculture or road traffic situations for example.In order to determine every parameter of the airplane the electric motor from Sineton and inspiration from other small airplanes composed the starting point. Some important specifications were a maximum weight of 25 kg, a cruise time of at least three hours and a cruise speed of at least 100 km/h.In order to reach these goals and determine the parameters of the airplane, the literature General Aviation Aircraft Design: Applied Methods and Procedures by Gudmundsson and the software Matlab were used. This literature contain detailed sections that process every aspect of an airplane. By using this literature, the choice for instance fell upon using a four-bladed propeller in order to minimize the diameter and a semi-tapered wing with an airfoil from NACA. The wing and the tail were also analyzed in the software XFLR5. When all the parameters of the airplane started to take shape, evaluations were made in order to secure adequate performance regarding take-off, climb, stability and landing. The choice of material and power plant are the ones that affect the amount of CO2 emission the most. Since carbon fiber has a higher yield strength and a much lower density, the construction doesn?t need as much material. This some what negates the fact that carbon fiber is much more expensive than aluminium. Besides a lighter airplane requires less energy in use. Concerning the source of energy, lithium-ion batteries does add to CO2 emission in its manufacturing state. In this case it will take around 200 hours of use before the emission from e.g. gasoline would be have to become larger than the initial emission of the manufacturing of the batteries. With this said we consider the use of both carbon fiber and lithium-ion batteries the right choice concerning the environmental aspect for an airplane like this.