

Jet Pack Dreams Take Flight - edw519
http://www.news.com/Photos-Jet-pack-dreams-take-flight/2300-11397_3-6228153.html?tag=nefd.lede

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marvin
These dreams are about to make a hard landing.

Allow me to rephrase that - there is no _chance_ that jetpacks will be a
conceivable way of personal flight in the forseeable future. Imagine how
inefficient space rockets are: gravity drag constantly works against you and
at all times you have to create about 10N/kg of thrust just to keep from
falling down. And this is thrust you have to provide by expelling mass from
your engines. It will be a cold day in hell before it will be viable to use
this technique to stay in the air for prolonged periods of time. The problems
that make it difficult to climb into orbit are doubled for atmospheric flight
through mass ejection. (This is also why purely chemical rockets will _never_
turn into a cheap way of getting into orbit, another pet pieve of mine).

Until we should happen to master large-scale production and lightweight,
mobile storage of anti-matter (right, that's only going to be in like 50 years
or so anyway), wings and atmospheric displacement are the only viable ways to
achieve atmospheric flight of any significant duration. And among those, only
wings allow you to gain any significant speed. If anyone can point out a flaw
in my physics I would be delighted, but as far as I can tell this is the
reality we have to face. No amount of daydreaming is going to change Newton's
laws.

On the other hand, strapping your body to a set of wings while wearing an
aerodynamic suit and a lightweight chemical engine (like <http://www.jet-
man.com/prod/index.html>) could probably be a viable and exciting way to get
closer to the air. Unless my intuition is off you will not get very good fuel
efficiency, but some people think that modern sailplanes or experimentals are
not a sufficiently fun and cheap way to stay in the air and travel long
distances fast.

And even that being said, politics is a much greater impediment to the
development of aviation than physics has been for the last 100 years. Google
"aviation lawsuit" for a small taste of what anyone not playing _squarely by
the book_ have in store for them.

~~~
mikelikespie
If you go to the website of the company it says for promotional and
entertainment use. Nobody was really saying it's viable. It's quite awesome
though.

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jgrahamc
Wow. It's 1965 all over again.

<http://en.wikipedia.org/wiki/Bell_Rocket_Belt>

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zach
Surprised that there was no remark on how loud it is to have a hydrogen
peroxide burning rocket that close by. I was under the flight path of the
Rocketman at last year's Tournament of Roses Parade. It was very cool but also
the loudest noise I've ever been exposed to.

<http://www.rocketman.org/events/RoseParade/>

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dskhatri
There are already untethered jetpacks out there!
<http://www.jetpackinternational.com/video.html> There are more videos on
YouTube somewhere. Try searching "jet pack rose parade" or "jet pack wired
nextfest"

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andyn
Looks like a lot of fun - a pity it only has a flight time of ~75 seconds at
the moment (it does say they'll get it up to 35 minutes ... we'll see how that
pans out).

