Simanaitis Says

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MY 21ST-CENTURY Flame Eater atmospheric engine is a technical delight that traces its origin back 300 years to the dawn of mechanical power.

The very earliest of engines were of this atmospheric variety. That is, by one means or another they achieved a less-than-atmospheric pressure in a working chamber containing a piston; then they depended upon atmospheric pressure to drive the piston inward. This is opposite to ordinary internal combustion, wherein increased pressure of combustion drives a piston outward.

Either way, if the piston is connected to a crankshaft, its linear motion gets translated into crankshaft rotation—and useful torque.


An 18th-century Newcomen engine, used to pump water from British mines. The walking beam takes the place of a crankshaft in transferring the reciprocation.

Thomas Newcomen devised the first practical atmospheric engine in 1712. There’s a schematic of its operation at

The principals of Flame Eater operation are similar. I saw my first example at the Coolspring Power Museum (see The Flame Eater’s general demeanor charmed me—and I had to have one.


My Flame Eater atmospheric engine and some of its necessities. Source: P.M. Research Inc.

There are plans and kits available. But fortunately, for those not handy with home lathes and the like, there’s also P.M. Research Inc. ( that sells a very nicely executed Flame Eater and its associated hardware for $355.

Here’s how the Flame Eater functions: Its piston reciprocates in its heavily finned cylinder. The cylinder has a slide-valve port in its head; it’s open to atmosphere at the other end.


A close-up of the cylinder port and slide valve. The wick is at below right.

The engine’s “flame eating” comes from an alcohol-fueled wick burning next to this port. As the piston moves away from Top Dead Center, an auxiliary push/pull rod opens the port’s slide valve. These actions cause a partial vacuum within the cylinder that sucks flame and hot air into the head.

As the piston reaches Bottom Dead Center, the slide valve closes and the air trapped within the finned cylinder cools.

At this point, the pressure within the cylinder is now less than atmospheric pressure, and the latter drives the piston back toward Top Dead Center, thus storing energy in the flywheel.

When the piston reaches Top Dead Center again, the cycle is completed. With the flywheel’s help, the piston returns toward Bottom Dead Center, the slide valve sucks in more flame and hot air, and the engine’s operation continues.

All this occurs with gentle mechanical clacks of the slide valve and little pops of air exiting the port.

A Flame Eater doesn’t produce much power. Indeed, it operates so marginally that its Owner’s Manual says the Flame Eater “generously rewards those who have patience.”

I add a bit of ritual too. First, to get myself in the mood, I pin on my Coolspring Power Museum badge.


Coolspring Power Museum badge; optional but helpful in Flame Eater operation.

Next, per instructions, I dust the piston and cylinder with Extra Fine Powdered Graphite and apply dollops of Marvel Mystery Oil to the points requiring liquid lubrication.

Then I moisten the cotton batten within the Fuel Cell with denatured alcohol. Note, there’s drama in obtaining lab-quality denatured ethyl alcohol, which contains only trace water; mine is only 0.03 percent H2O. Alas, the stuff also apparently has use in the home druggie trade.

Adjust the moistened wick, light it and move the flame adjacent to the slide-valve port.

Spin the top of the flywheel aft smartly. And if the engine isn’t feeling cantankerous, it reciprocates into operation.

My Flame Eater works best when accompanied by classical music.

All in good fun. ds

© Dennis Simanaitis, Simanaitis, 2014


  1. Bill Urban
    January 14, 2014

    Calling all gokarters . . .the superiority of the two-stroke is confirmed!

  2. Alessio
    February 9, 2019

    good evening. I have a motor like his (flame eater) is bigger but I can not start it. could you give me some advice. thanks a lot Alessio

    • simanaitissays
      February 9, 2019

      The best advice is to contact the company I cite, and ask whether they might send you an Owner’s Manual. It suggests adjusting the tension of that sliding valve. This is the most delicate aspect. I found the manual very helpful.
      Good luck.

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This entry was posted on January 13, 2014 by in Sci-Tech and tagged .
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