The idea of flying a plane that uses solar power is smart and good for the environment in the long-run. Many people may be warming up to the concept of a solar airliner, but there are other issues to consider. Indeed, the idea is good, but the plane that belongs to this category cannot transform the aviation industry in future.
The primary issue that arises in the development of solar aircraft pertains to their sustainability. Many people may be interested in knowing if solar planes can sustain long distances and heavy loads on solar power only. In other words, the main issue is about the performance of solar planes.
Factors such as power, weight and its ability to glide determine the performance of each solar aircraft. There is a mismatch between power generation capabilities between solar and conventional planes that use jet fuel. Solar planes cannot sustain heavy loads and match the speed of the traditional aircraft.
What Is The Average Power Required To Fly A Plane?
The maximum power that a plane with about 12,000 solar cells can capture from the sun is about 50,000 watts. Not all the power is captured, and it is noticeable that some solar cells are not efficient hence some energy is lost during the process. This power may not be sufficient enough to fly a plane depending on two variables namely weight and the plane’s ability to glide. These variables determine the amount of power required for an aircraft to fly.
More large planes need to fly faster for them to stay afloat. More weight means that a heavy aircraft needs more power to operate since it needs to throw sufficient air downwards to stay afloat. On the other hand, a light plane requires less energy to be able to fly compared to heavier aircraft. A solar plane is light hence can operate with little power, and it can also travel at less speed.
The Plane’s Ability to Glide
A plane that is capable of gliding for a long distance has a high glide ratio. This kind of aircraft has a massive wingspan that helps it to stay afloat, and the other issue is that this kind of plane is light. For instance, a solar plane has a large glide ratio since it is made of light material. However, the glide ratio of a more large plane is lower than light aircraft. A light plane is energy efficient, and this also has a bearing on its speed.
Limitations of a Solar Plane
A solar plane cannot be used for commercial purposes since it needs more power to fly. Initially, a solar aircraft is light, but its weight increases the moment you try to expand it to accommodate more people. The bigger the plane becomes, the more significant the amount of power required to fly it.
Against this background, it may be challenging to use a solar plane for commercial purposes. The power it captures from the sun may not be sufficient to cope with the increased weight. Each size of an astral aircraft has a limit regarding the number of solar panels that can be put on its wings. The number of solar panels affects its suitability for use as a commercial plane that can carry a heavy load.
The other factor why solar planes are not ideal for commercial purposes is that they fly at a low speed of about 25 to 30 miles per hour. The reason is that they have large wingspans that help them to remain light and stay afloat. Thus, a solar aircraft can therefore not go beyond its optimum speed.
The speed of 30 miles per hour is not viable for commercial business at all since air transport is viewed as the fastest mode of transportation. In contrast, commercial planes can cruise at an average of about 500 miles per hour or more than 800 km per hour.
The other limitation of a solar plane is that it solely relies on solar power for it to fly. This means that it can fly longer distances during the day when it can directly capture more energy from the sun. At night, solar planes use energy stored in batteries, and they cannot generate more power once the batteries run low.
The primary challenge of converting a solar aircraft into a commercial plane is that it is difficult to operate at night. The furthest distance it can fly at night with power stored in batteries is about 1,000 km. This means that the solar plane is not reliable for commercial purposes since it cannot sustain long-haul flights in particular.
There is still a long way to go concerning building a viable commercial solar plane that can carry more than 200 people. More energy dense batteries need to be developed, but this seems to a challenge that is difficult to achieve in the short run.
Different Solar Planes That Have Flown
Different solar planes have been designed since the introduction of the idea of solar aircraft. Some of the aircraft have been able to fly and are still being used while others have been retired. The following ten solar planes are good examples of aircraft that have flown for some time.
Solar Impulse, Solar Impulse 2
The Solar Impulse is a Swiss aircraft that uses solar energy only to fly. Designed by the Swiss Federal Institute of Technology under Bertrand Piccard, the primary goal of the Impulse was to fly around the globe using solar power only.
Source: Solar Impulse
The Solar Impulse is a single-pilot aircraft, and it has a wingspan of 70-meters. Its wings are covered by monocrystalline solar cells, and it has battery packs to store energy that can be used to power the plane during the night. The aircraft has already flown, and there are plans to engage on a continental journey from Spain to Morocco.
NASA designed the Helios plane, and it had a wingspan of 247 feet or 75 meters. The large wingspan enabled the aircraft to fly using little solar energy since it could glide. The flight was also made of a lighter material that helped it to fly long distances. However, the Helios solar due to unfavorable weather conditions the plane broke up and fell into the Pacific ocean in June 2003. Not to be confused with Helios Airways Boeing crash.
AeroVironment, NASA designed the Centurion around 1999, and it entirely used solar power as the source of energy. This solar aircraft can reach an altitude of about 100, 000 feet. The higher elevation helps the plane to consume less energy when flying.
Source: NASA Photo / Tom Tschida
The Centurion also flies at a speed of 12.5 miles per hour, and this speed is not ideal for travel. The plane is still in its development stage, and different things ought to be taken into account to improve its efficiency.
The Zephyr is another example of a solar plane that still flies, and QinetiQ designed it. One major outstanding feature about this particular aircraft is that it could travel at a speed of 155 mph. This level of speed is comparatively higher than other types of solar planes.
The Zephyr solar plane is also capable of flying at a higher altitude of 132, 000 feet. It can fly for several months at this altitude, and more research needs to be conducted to ascertain its efficiency.
The Pathfinder Plus was developed between 1997 and 1998 by AeroVironment, NASA. It consisted of extended wings, upgraded motors and it used solar arrays that were more efficient. Other key features of the solar plane include telecommunications platforms. This model is an extension of the original Pathfinder, and it has improved characteristics.
It can fly at a higher altitude of 24470.868 meters, and it represents a newer version of the Pathfinder. It is part of NASA’s Environmental Research Aircraft. The solar plane is still undergoing development, and it is used as the basis for research.
The Solar Challenger is another solar aircraft that was designed by AeroVironment, Dupont Corporation. Its weight is 90 kilograms, and it has a wingspan of 14.3 meters. It can reach an altitude of 12,000 feet. Generally, this is a small aircraft, and it was specifically designed to fly from Paris to England. The plane is on display at the National Air And Space Museum in Washington, D.C.
The Sky Sailor is another exciting model of solar-powered plane that was designed by the Swiss Federal Institute of Technology in Zurich. The aircraft was specifically designed for future use in space searches especially the mars.
The Sky-Sailor plane is generally smaller, and it weighs 2.6 kg. The plane also has a wingspan of 3.2 meters, and it is light enough to fly long distances without anyone operating it. The aircraft is also ideal for research purposes.
The SOLITAIR uses solar power only when flying and DLR Institute of Flight Systems designed it. It has a wingspan of 5.2 meters, and it can fly unmanned. It is comparatively smaller than other solar-powered aircraft.
The Solitair was explicitly designed for conducting research, especially in the north European latitude. It can fly long distances without anyone controlling it, and it seems to be a good aircraft that can be used for further research to develop solar-powered planes.
Solar-Powered Robot Bird
The Solar-Powered Robot Bird is capable of flying at an altitude of between 30, 000 feet and 40, 000 feet. The University of Missouri – Rolla developed the plane. One notable aspect about the aircraft is that it can fly unmanned and it also features flapping wings like a bird.
The solar-powered robot bird uses thin-film solar arrays, and it has a unique shape to make it more energy efficient. It is also perfect to inspect the outer space. This particular aircraft can go a long way in the sky, and it is also ideal for research purposes about solar-powered planes.
The SoLong aircraft was designed by AC Propulsion, and it uses solar power only to fly. The plane can fly for more than 24 hours continuously using solar energy stored in its batteries. The aircraft can also quickly recharge its power during the day when there is sunlight. It is very efficient regarding energy consumption.
The Future Of Solar Planes
The idea of a solar aircraft is a noble one since it helps in promoting efforts to develop clean energy technologies. According to different studies, conventional planes that use combustible fuel are responsible for large volumes of CO2 emissions. These greenhouse gasses cause damage to the atmosphere, and this is an issue of concern to people concerned about their welfare.
Greenhouse gasses contribute to the phenomenon that is commonly known as global warming. This scenario results in the earth overheating and leading to various consequences. These adverse changes in the climate can impact the welfare of the people. The life of animals can also be affected as a result of global warming.
The idea of smart energy in the form of solar energy is commendable since it helps in reducing the number of emissions into the atmosphere. The use of sustainable energy in the aviation industry is a noble idea. Smart power can help address the challenge posed by conventional planes to the environment. However, specific problems can also be encountered since solar planes may not be able to match the performance of heavy planes.
The primary challenge associated with developing solar planes into commercial aircraft is related to the aspect of power limitations. The maximum capacity of energy that a solar plane can generate is not able to power a heavy commercial aircraft. More energy will be required, and this challenge cannot be met since solar power can only work on small planes.
It may also be challenging to operate solar planes during the night for commercial purposes since they may run out of power. The other issue is that solar planes are designed in such a way that their speed cannot by any chance match that of heavy planes. A solar plane is very slow, and it is not ideal for commercial business.