Solar aircraft is the evolutionary concept. Many attempts were made to bring this concept to reality. NASA is working on the concept from about 1980’s. During this time NASA is successful in developing the various working prototypes of the machine which includes Pathfinder, Pathfinder Plus, Centurion, Helios Prototype etc. For detail see also Concept of The Solar Aircraft.

This solar aircraft, from NASA, also have basic principle same as the other normal aircraft. But there is change in the prime energy source i.e. from fossil fuels to solar energy. This has lead to change in its construction and parts.

Construction and Working of various parts of Solar Aircraft

(Mainly focus here the parts of Helios Prototype which is latest version):

Bifacial Silicon Solar Cells

their constructional details, efficiency up to 22.5 %, efficiency and temperature inverse relation [More information can be found in any Solar Power Books], cooling of these panels by air passage and its effects [Refer NASA paper Anthony J. Colozza, Convective Array Cooling for Solar Power Aircraft –NASA –2003/212084.].

Regenerative Fuel Cells

i.e. H2-O2 fuels cell, working of fuels cell, High Energy capacity up to 400-600 W-Hr/Kg. and its use for night hours. During day charging of Fuels cells by means of solar energy.

Frame

Main components carbon fiber, glass wool, epoxy. Use for support to panels.

Wing

Wing span 247 feet, used for aerodynamic lift, minimize drag, streamlined cross section.

Motor

2hp motor, permanent magnet type specially designed with minimum number of parts ( only 3 moving parts viz. two bearings and spider armature ) to avoid maintenance, works for all time while aircraft is in the air, drives the propeller.[Refer NASA site].

Propeller

Provide necessary thrust force, two blades, aerodynamic shape, driven by motor, speed controlled by computer in pod.

Pods

Supports body on ground, contains on board computer, fuels cells equipments, wheels to run on ground, aerodynamic streamlined shape to reduce the drag.

References:

[1]  Anthony J. Colozza, Convective Array Cooling for Solar Power Aircraft –NASA –2003/212084.
[2]     http://www.nasa.gov/centers/dryden/news/FactSheets/FS-034-DFRC.html

[3]    http://en.wikipedia.org/wiki/Helios_Prototype

Related posts:

1. Concept of The Solar Aircraft

Today, we are using the conventional fuels like coal, petroleum products, LPG etc. on very high scale for the purpose of industrialization, transportation, domestic purposes etc. The emissions due to use of conventional fuels has lead to many problems like air pollution, water pollution and most recent is the global warming. Another important problem is the high cost of these fuels. Again, all these conventional fuels, we have, are limited in nature.

All these problems regarding to the conventional fuels and there sources have lead the engineers to think about another sources of energy. That is why the non conventional fuel sources (Renewable Energy Sources) have got a lot of importance today. They include Wind Energy, Tidal Energy, Geothermal Energy, Solar Energy etc.

Solar Energy is one of the important source of energy from the non conventional energy sources. Maximum places in the world get the adequate amount of the solar energy, in short, it is easily available, it is free and will be long lasting. Today, we know many appliances working on Solar Energy such as Photovoltaic cell, Solar Water Heater, Solar Water Distillator, Solar Cooker etc.

NASA, ERAST program under which solar aircraft research was done. [More information can be found on NASA website ].

The Brief Developments in various Models of Solar Aircraft are as belows:-

1. Pathfinder:::100feet wingspan and 6 propellers operated.
2. Pathfinder Plus:::120 feet wingspan and 8 propellers operated.
3. Centurion:::206 feet wingspan and 14 propellers operated.
4. Helios Prototype for high altitude configuration:::247 feet wingspan and 14 propellers
5. Helios Prototype for Long endurance configuration:::247 feet wingspan and 10 propellers.

Advantages of Solar Aircraft:

1. Uses Solar energy which is long lasting, non polluting and easily available source of energy.
2. This can work like Relocattable satellite in the sky (it can do work like satellite as hovers at very high height.)
3. Operated remotely so no danger of human life.
4. Can be sent to missions lasting many days, months as no need to re-fuel it.
5. Hovers much higher altitudes than normal air traffic. So no air traffic problems.

For constructional details of solar aircraft see Construction of The Solar Aircraft

Limitations:

1. Can not carry heavy loads.
2. Very high cost of construction (Mere silicon solar cells of Helios Prototype costs upto $9 million!).

Practical Applications:

1. Instrument for crop management, fisheries, coral reefs, forests etc.
2. For monitoring the changes in weather as fly much above the normal weather conditions.
3. Can monitor strength and change in directions of hurricanes as fly above them easily.
4. In future, can act as space tower and provide service like high speed broadband etc.
5. Aircraft made with same technology can be sent to other planets to make space research.

References for Study of The Solar Aircraft:

[1] Anthony J. Colozza, Convective Array Cooling for Solar Power Aircraft –NASA –2003/212084.
[2] http://www.nasa.gov/centers/dryden/news/FactSheets/FS-034-DFRC.html

[3] http://en.wikipedia.org/wiki/Helios_Prototype

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