That may sound like a silly question, but thin-film solar cells are pushing the boundaries of lightness and efficiency that will make them viable candidates for use on aircraft. Looking back at earlier achievements demonstrates the great things that can be done with limited resources. Eric Raymond, for instance, made a solar-powered flight across the United States in 1990 on amorphous solar cells that were only about two percent efficient. His Sunseeker Duo, which he flies around Italy and Switzerland with Irena, his wife and co-builder, has modern thin-film cells that are 23-percent efficient – a ten-fold gain. Before that, the earliest two solar-powered flights were charged by big, round solar cells, not terribly efficient and lacking full coverage of a wing because of the gaps between cells. Fred To in England and Larry Mauro in America did what they could with these disadvantages and managed successful, but short, flights after hours of charging small on-board batteries (also relatively inefficient). …
