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
