Hero’s Aelipile


Hero (also known as Heron) was born around 10AD (dying in 70AD) in Alexandria, then part of Roman Egypt.

Despite the Roman and Egyptian mention, Hero was a Greek… and is considered one of the early world’s greatest mathematicians and engineers.

He designed, and I assume built, an aelipile or aelopile, that was the first jet motor invented about 2,000 years ago – obviously long before the jet plane was invented. Whatever you want to call it, it was essentially an engine.

Now… because this wasn’t invented for an aeroplane et al, I admit that simply because this is a ‘jet’ engine, I am using that premise to present this cool story to you.

Much of Hero’s original writings and designs have been lost, but some of his works were preserved in Arabic manuscripts.

We do know that he wrote at least six texts:

  • Pneumatica, described machines that could work via air, steam or water pressure;
  • Automata, a description of machines which enable wonders in temples by mechanical or pneumatical means (such as the automatic opening or closing of temple doors, or statues that pour wine, etc.);
  • Mechanica, preserved only in Arabic, written for architects, containing means to lift heavy objects – perhaps like the stones used to build the pyramids earlier;
  • Metrica, where he explains how to calculate surfaces and volumes of different types of objects;
  • On the Dioptra, ways to measure lengths. It features an odometer (to measure distance traveled)and the dioptra (an astronomical and surveying instrument); 
  • Belopoeica, a description of war machines
  • Catoptrica, discussed how light travels, reflections and the use of mirrors in ways more than sitting around looking at one’s self.

Hero’s inventions include:

  • a primitive, programmable robot… but really, an automaton;
  • a water organ;
  • a coin operated Holy Water dispenser;
  • a fire engine;
  • a fountain that worked via steam pressure;
  • and, of course, the jet engine he called the aelipile.

In the image at the top, Hero’s aelipile is described as a simple, bladeless radial steam turbine engine that spins when the central water container is heated. Obviously when the water is heated, it turns to steam.

Torque is produced when the steam is forced out of the turbine.

Want to see it in action?

Basically… this is a steam turbine… invented nearly 1700 years earlier than it was ‘invented’.

What the hell is an aelipile, anyway?

The word is a mix of Greek and Latin. Aeolus is the Greek god of the win and air. Pila is a Latin term meaning “the ball of”… ergo, and I use that word correctly, “the ball of Aeolus”.

About mreman47

Andrew was born in London, UK, raised in Toronto, Canada, and cavorted in Ohtawara, Japan for three years. He is married, has a son and a cat. He has over 35,000 comic books and a plethora of pioneer aviation-related tobacco and sports cards and likes to build LEGO dioramas. He has written and been an editor for various industrial magazines, has scripted comic books, ghost-written blogs for business sectors galore, and hates writing in the 3rd person. He also hates having to write this crap that no one will ever read. He works on his Pioneers Of Aviation - a cool blog on early fliers - even though it takes him so much time to do. He also wants to do more writing - for money, though. Help him out so he can stop talking in the 3rd person.
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