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Solar powered composites plane

Atkins | 02 May 2014 | Comments

I recently read an interesting article “Sun + composites = long-duration solar-powered flight” in Composites World (http://www.compositesworld.com/blog).

The article looks at two aircraft that aim to be entirely powered by solar energy. Because weight is super critical on these aircraft, significant use is made of composite materials for both designs. Indeed the article makes the point rather strongly in saying “Both planes likely could not function as planned without the use of carbon fiber composites.”

I rather like the closing paragraph indicating closeness in broad concept to the Wright brothers’ Kitty Hawk aircraft. Way back at beginning of the last century, the first aircraft needed to be made from strong lightweight materials and construction methods that were well understood. They chose wood and fabric glued together, which was a logical choice. In effect this was a “composite” design.

The development of aircraft changed in the 1915 with the Junkers J1 which changed the fundamental design approach to more monocoque stressed skin thinking, as opposed to a wooden frame alone being the primary load carrying structure. But it was not really until the mid 1930’s that advances in metal technology together with improved understanding methods drove aircraft design into all metallic construction for the majority of aircraft. This approach remained mainstream for many decades to come.

Of course, composite materials have advanced significantly over the past decade, especially with respect to resin formulations and manufacturing processes. These have enabled a shift away from all metallic construction for aircraft to Boeing’s 787 and Airbus’ A350 as well as these ultra-lightweight solar powered craft. It is interesting that unlike these two airliners, the Solar Impulse 2 takes a broadly similar construction approach to the Kitty Hawk, using carbon fibre rather than wood for the frame work, as the article notes “what comes around, goes around”.

For me this just goes to show how composite materials are not simply seen as an alternative solution for one material, nor indeed, one type of construction concept; they really do offer a wide range of benefits for designers.