Flying Only with the Heat of the Sun

If you picture a flying machine, you probably imagine a craft which is heavier than air, somehow kept aloft with wings or propellers. Heavier-than-air flight dominates discourses about aviation. “Sustainable” crafts are designed to be as light as possible (whilst remaining heavier than air), so that they require less energy from whatever renewable source they use for lift. These machines include human-powered planes such as those using pedals to rotate a propeller. Lighter still are kites and gliders, which remain heavier than air, but rely on air resistance and lighter air around them to fly.

Less discussed are flying machines which are lighter than the air they fly through because the weight of their materials and passengers is counterbalanced by the hot air or light gases they contain. [1] Perhaps this is because most of us experience flight in passenger airliners, not Zeppelins. In theory, making lighter-than-air flight sustainable is simple: heat a container full of air with sunlight so that it rises. In January 2020, Leticia Noemi Marqués flew freely in the Aerocene Pacha solar balloon, the first Fédération Aéronautique Internationale certified fully-solar, untethered, manned flight. Previous flights of this kind went uncertified or relied on propane burners or inflation generators [2]. Aerocene Pacha flies on solar energy not from solar panels or batteries but absorbed directly in the envelope (the fabric of the balloon). [Read more…]

Helium Powered Drones

Airpup is an exceptionally small kite balloon (aka an aerostat), which is a quiet, easy to use alternative for drones. Kite balloons can fly for days. They have no active controls, no software, no moving parts — they just point into the wind and follow where towed.

Kite balloons can be used for aerial photography, as a replacement for a radio tower, or for capturing weather data. Airpup is based on early 20th century kite balloons. It is the first new kite balloon design in 25 years. See also: Kite aerial photography.

Obsolete Technology Prints and Photograph Collections

Tissandier collection

Three wonderful collections from the Library of Congress, showing obsolete technologies.

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Floating Citadels, Powered by Wind and Water Mills

floating citadels

This engraving, published in 1798, shows the gigantic St. Malo raft, designed in 1791 during the French Revolution. The engraving informs us that this extraordinary structure was 600 feet long by 300 broad, mounts 500 pieces of cannon, 36 and 48-pounders, and is to convey 15,000 troops for the invasion of England. In the midst is a bomb-proof, metal-sheathed citadel.

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Airships Past and Present, by A.Hildebrandt (1908)

airships past and present

Airships past and present – together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon” by A. Hildebrandt, captain and instructor in the Prussian Balloon Corps (1908). Pictures, table of contents and list of illustrations below. Related: Camping in the clouds – the zeppelin that never lands / Green slow air cargo / Kite aerial photography.

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