Solar-powered aircraft have become a reality relatively recently, although solar cells have been known for over 100 years and electric motors for over 150 years. This has become possible due to the development of high-efficiency solar cells, as well as lightweight electric motors and batteries.
Instructions
Step 1
The solar-powered aircraft obtains the energy required for flight from an array of photodiodes. Unlike their counterparts, designed only to detect the presence of light, power photodiodes are flat and have a large area. They work not in a photodiode, but in a photovoltaic mode, that is, they generate electricity themselves.
Step 2
One photodiode, regardless of the area, generates a voltage of about 0.5 V. But the maximum load current of the device depends on the area in direct proportion. If you multiply the current in amperes by the voltage in volts, you get the power in watts. Cells can be connected to form batteries like conventional galvanic ones. The parallel connection is used to increase the current, and the series connection is used to increase the voltage. On a bright sunny day, there are several hundred watts of light energy per square meter. How much will come out of the battery depends on its efficiency.
Step 3
The efficiency of a cheap solar battery is small - from 5 to 10 percent. With the power required for flight, it will turn out to be heavy - an airplane with it is unlikely to lift itself. Only recently have relatively inexpensive photo batteries with an efficiency of about 30 percent been obtained. It is they who are put on experimental aircraft models. They are located on the wings, which have a large area.
Step 4
Brush motors provide the best power-to-weight ratio. In the past, they were only used in cordless models powered by wire. And in this case, they had to be forced, which led to overheating of the windings and rapid wear of the brushes. Now many parts of such engines are made of lightweight but durable composite materials. The supporting structures of the aircraft themselves are also made from them.
Step 5
Even large solar-powered aircraft are not yet made manned. But cords have not been used to control them for a long time. Commands are given over the radio channel, and in response, the operator receives an image from the camera in real time. All this became possible thanks to the miniaturization of electronic devices. Even TV cameras and satellite navigators are made so light that they can be lifted by an electric plane, where every gram counts.
Step 6
But suddenly the weather changed - the sun disappeared behind the clouds. Despite this, the plane continues to fly. He receives energy from accumulators - but not heavy lead ones (he could not lift them either), but light lithium-ion ones. Exactly the same, only small, is installed in your mobile phone. And if you ever find yourself at an air show or a model show, where a solar aircraft will be shown, be sure to take your mobile phone out of your pocket and film the flight.