Let's say somebody knows all about aircraft and how they fly and all the physics involved and stuff. Basically, he knows how to make something fly.

Now this plane guy somehow ended up in medieval times, and despite wanting to get back home, decides to go ahead and show the people there how to fly. My question is, how far can aircraft advance with medieval tech?

  • $\begingroup$ What exactly did Otto Lilienthal do which could not be done in 1400, provided somebody thought to do it? (You did research Otto Lilienthal, of course, seeing as how you are interested in early flying machines.) For that matter, what exactly is there in the aerostat of the Montgolfier brothers which could not be made in 1400? $\endgroup$
    – AlexP
    Oct 25, 2020 at 17:47
  • $\begingroup$ How concerned are you about the non-engineering/construction elements? Namely, for someone to build (and probably fail) a couple experimental aircraft in medieval times they'd need to either be nobility or directly sponsored by nobility. $\endgroup$
    – Dragongeek
    Oct 25, 2020 at 17:55
  • $\begingroup$ @Dragongeek, not much, mainly I'm focusing on the materials needed and limits from the technology level. $\endgroup$ Oct 25, 2020 at 17:56
  • $\begingroup$ With all time traveling scenarios I think a smart strategy is this: The most important thing is to demonstrate the concept and prove it works, then after securing funding they go around building the ultimate medieval thing. Think of it this way. Say your character has a merchants income and resources to build an aircraft. That is fine but they are still greatly limited. Now say they have that then go about showing it to the king and convincing him. After that you have all the resources of the crown working to support you and make your aircraft. Money, labor, resources...etc just got better. $\endgroup$
    – Seallussus
    Oct 25, 2020 at 18:02

1 Answer 1


First, heavier-than-air flight is right out although you can probably construct a primitive glider. The materials science of the time could simply not produce materials which are strong and light enough or produce an engine which is capable of enough power density to overcome a heavy air-frame:

  • Airframe construction materials:

    • Aluminum was among the rarest metals available to humans, rarer than gold in medieval times because it was mainly found in meteoric or minuscule deposits. The ability to process bauxite into aluminum requires much more complex smelting processes than were available at the time. "Inventing" the Bayer process would be a massive undertaking in itself

    • Balsa wood, commonly used in model- and retro- aircraft construction due to its extremely low density is found only in central and southern America, which are inaccessible to medieval powers. With the wood types available to a European Medieval setting, I find it unlikely that one is going to be able to find a wood which is light enough to build a powered aircraft.

  • Power sources:

    • Steam power: While others in the past have successfully flown steam powered model aircraft and even a couple full-scale heavier-than-air aircraft capable of level flight, the concept never really took off. Steam power simply has too low an energy density, although it is probably the simplest form of engine to build.
    • Internal combustion: Building an internal combustion engine from scratch in a medieval setting would be a herculean undertaking. Likely technically possible, and you'd probably use alcohol as fuel, but incredibly difficult. Highest energy density though, and having an overpowered engine can make up for a too-heavy airframe. If you need to handwave one component, this would be it.
    • Jet engine: Forget it.
    • Electric motor: Surprisingly, probably the easiest engine to build as you'd only need copper wire and some magnets. Unfortunately, would be entirely useless as even today (2020) we still struggle building electric aircraft because we simply can't make light enough batteries for it to be worth it.
    • Man-power: Technically possible, but requires top fit athleticism and space-age materials and manufacturing techniques to build an aircraft that's light enough. Would not be possible.

Now, with that out of the way, you can definitely build a lighter-than-air aircraft like a hot-air balloon, airship, or zeppelin. It would be difficult and expensive, but doable and a great demonstration of scientific knowledge and principles.


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