Very Small Engines: Why shrinking internal-combustion doesn't scale the way we want

The post and the punchline

It has been reported that blogger Scott Locklin published a provocative takedown of the idea that internal-combustion engines can be miniaturized indefinitely and remain useful. The piece, which surfaced on Hacker News and his own site, argues that once you push displacement down to the “very small” range, physics and practicality conspire against efficiency and reliability. In plain terms: tiny engines lose heat faster, suffer relatively higher friction and lubrication headaches, and demand manufacturing tolerances that make them an expensive headache rather than a clever solution.

The technical gripe (and the obvious bit nobody wants to hear)

Locklin allegedly points to familiar scaling problems — surface-to-volume ratios, parasitic losses, and thermal leakage — and reminds readers that these aren’t mere engineering nuisances but hard limits. Want a coin-sized engine to power a drone for hours? Good luck. Electric motors and batteries, he argues, beat small IC engines on weight, simplicity, and cost at that scale. That’s not new science, but his blunt framing cuts through a lot of techno-optimism: 3D printing and clever geometry can help, sure, but they can’t erase thermodynamics.

The human angle: nostalgia versus cold efficiency

There’s a little grief in the piece for the tinkerer who loves the smell of fuel and the mechanical kid-in-the-garage joy of an engine running. Locklin’s tone mixes practical critique with a nod to hobbyists — it’s OK to love tiny engine projects, he seems to say, just don’t confuse that love with industrial promise. Isn’t that always the dance in tech? We cling to mechanical romance while the market quietly moves toward cleaner, simpler solutions. A cultural moment, not just an engineering one.

Why this matters

If Locklin’s thesis holds, the headline takeaway is clear: don’t bank the next generation of micro-vehicles or consumer gadgets on reinvented mini internal-combustion engines. Expect continued momentum for electric drive at small scales, and a persistent but niche role for tiny combustion devices in hobbyist and specialty pockets. Call it pragmatism, or call it the day technology shrugged and told romance to take a back seat. Either way, the debate is a useful reminder: not every problem needs a clever mechanical workaround — sometimes the simpler path is the smarter one.

Sources: scottlocklin.wordpress.com, Hacker News