Trying To Run Engines On Gunpowder Sounds Like A Good Way To Get Rid Of Excess Fingers
Piston engine designs have existed since the 1400s. Even Leonardo da Vinci experimented with various designs. And throughout the centuries, engineers have used just about every sort of fuel imaginable to run their piston engines, from steam to gasoline. In 1807, two French brothers even made an engine that ran on moss.
One of the earlier engine fuels experimented with was gunpowder, the same stuff used in ship cannons and modern firearms. However, gunpowder proved inefficient and too volatile for engine use. Which is why the only real gunpowder engines used today are homemade experiments, and even those are probably best to stay away from if you like your current number of fingers.
Okay, so technically a machine gun is a gunpowder engine, as it uses the exhaust gases from ignition to reset the firing cylinder. However, we're talking about working engines that generate rotational power. And while gunpowder can work, it doesn't work well enough to make its danger worthwhile.
Gunpowder has been tried for centuries and still hasn't gained traction
The first functioning internal combustion engine of any kind was invented by revolutionary Dutch scientist Christiaan Huygens in 1673, and it ran on gunpowder. It was effectively a big vertical cylinder, with gunpowder in its base that would fire a piston upward. As the exhaust gases cooled, the piston, attached to a pulley via rope, could mechanically lift heavy objects on its way back down. It wasn't very efficient, though, since the explosives blog Standing Well Back quotes an unnamed source as saying the 7-foot-tall cylinder could only lift "seven or eight small boys." (Was that the standard system of weight measurement before the metric system?) However, Huygens' engine laid the groundwork for the internal combustion we use today.
In 1807, British engineer George Cayley designed another gunpowder engine, but this time with two cylinders: one larger lower cylinder and one smaller cylinder stacked on top. Gunpowder would be placed in the lower cylinder, which would then ignite from a candle-heated metal rod, and the expanding gasses would push a piston inside the upper cylinder. Cayley, being the father of modern aviation, was interested in an engine to power an aircraft, but eventually moved on to different designs.
People are still messing with gunpowder engines even today. "MythBusters" tried to create a gunpowder engine in 2006 but failed. In 2007, though, mechanical engineer Charlie Macklin succeeded in making a small steam engine run on gunpowder.
Macklin said his success came from making homemade gunpowder in large chunks, which he claimed helped sustain burns, like a road flare. The exhaust gases from such sustained burns powered his steam engine.
A gunpowder engine can work but it just isn't worth it anymore
It's easy to see why a gunpowder engine has always been attractive. It's cheap, explosive, and seems like a fun, interesting way to push a piston. In 1981, inventor Samuel D. Williams even was granted a patent for a gunpowder-fueled internal combustion engine.
However, gunpowder just isn't worth the effort, as it isn't anywhere near as energy-dense as gasoline or diesel fuel. Gunpowder has a specific energy output of 3 megajoules per kilogram while gasoline and diesel fuel output 46 and 45 respectively. So burning it slowly, like Macklin does, doesn't generate enough power to run any sort of useful engine. But if you pack a bunch of fine black powder into a typical combustion chamber, as "Mythbusters" found out, it becomes very explosive and hard to control, which can wreck the engine. So while gunpowder is great for firing something like a bullet, or a fast-chomping cutting tool, it isn't great for sustained power generation.
It's also just a pain in the neck to use. Since gunpowder is so volatile, it's difficult to make and store safely. It's also hygroscopic, so it easily pulls moisture from the air, which can drastically reduce its burn rate, making long-term storage even more annoying because it has to be airtight.
All of this is to say that a gunpowder engine might be a fun idea, and it has a long, fascinating history. But it just isn't worth the hassle. It's dangerous, ineffective, and much harder to use than traditional liquid fuels. So if you'd like to tinker with homemade engines, save yourself the headache, and the fingers, and stick to gasoline or diesel.
