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I am working on a 2D platformer game, and I'm trying to introduce a jetpack which would give a shinespark-like ability from Metroid series, i.e. it needs a run-up to a certain speed, at which the engines become operational and can be fired. The catch: I'd like to stay as hard-sciencey as possible, so the alien supertech from Metroid is unavailable.

Considering modern day tech, the operation sequence reminds me of a pure ramjet which needs a good airflow before it can be fired. The problem is, a ramjet needs a run-up to something around 1 mach (or even more), which is too much for a running character (she's not Flash, although augmented to above-human abilities). Its final operational speed is also far too high.

Another possible engine is a pulsejet, especially a pulse detonation engine. It seems really promising: highly advanced, low operational speeds are possible (although less efficient), it seems like compact designs are possible. But it doesn't seem to specifically need a run-up to ignite (maybe the deflagration-to-detonation transition could possibly need it?).

So, what kind of engine could be used in a jetpack, that becomes operational at speeds of, let's say, 10-30 m/s, and allows to achieve operational speed of, say, 0,5 mach, without too much handwaving? Consider the atmosphere composition and pressure close to Earth-like (slight variations are possible as long as it stays breathable for non-augmented humans). It is implied that the device is either a production model or a working prototype, i.e. the need for a run-up should be justified by the engine technology itself, not an artificial restriction (like a broken/non-functioning pre-compressor, for example).

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  • $\begingroup$ Hrm...maybe weight restrictions prevented someone from putting a starter on the jetpack's engines, so you have to run up to get enough speed to windmill start them? $\endgroup$
    – Shalvenay
    Apr 26, 2015 at 3:04
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    $\begingroup$ @Shalvenay Seems a good idea. Could a starter for these compact engines be of a noticeably serious weight increase? $\endgroup$
    – Kelly Roadkill
    Apr 26, 2015 at 6:24
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    $\begingroup$ You also need a power source for that starter, whether it be a gas generator, pressure tank, or batteries... $\endgroup$
    – Shalvenay
    Apr 26, 2015 at 6:27
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    $\begingroup$ @Shalvenay totally reasonable. I think I'll stick with this "no-starter" version, coupled with some winglets from the answer by Samuel, to provide lift. Thank you. $\endgroup$
    – Kelly Roadkill
    Apr 30, 2015 at 13:32

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There is no such thing in the realm of hard-science. Speculation could be made on what might be possible in the future, but that would be , not . It's difficult to invent a fantasy technology using real technology.

The closest real life thing that comes to mind is the rigid-wing jetpack used by Yvess Rossy to power flight after jumping from a plane. His pack can't be used to take off from a stop, but has only gone as fast as 85 m/s, far short of your requested 170 m/s.

enter image description here

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  • $\begingroup$ I don't really think that a working jetpack with above specs is completely impossible with modern technology. The winged one looks inspirational, thank you. Another nice jetpack is by Troy Hartman. For now, it works when coupled with a paraglider, but it seems plausible that some near-future version will work standalone. Overall, the idea of coupling jetpack technology with some wing(let)s seems to be the closest to what I'm trying to implement. Thanks again. BTW, 0,5 mach is about half of your 340 m/s, but I'm ok with even lower speeds actually. $\endgroup$
    – Kelly Roadkill
    Apr 25, 2015 at 21:26
  • $\begingroup$ Oops, forgot to divide by two, thanks. $\endgroup$
    – Samuel
    Apr 25, 2015 at 22:38

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