

Jetpack helps soldiers run faster [video] - sizzle
http://researchmatters.asu.edu/videos/jetpack-helps-soldiers-run-faster

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lmg643
Really interesting idea. As an amateur runner myself, I'm always interested in
how I can run faster.

My experience with personal fitness is this - there's never just "one thing"
you can do to make yourself run faster. Your entire body needs to be trained
to the level to maintain performance.

In the case of a jetpack - that means hips and legs have to be able to turn
over rapidly, heart and lungs need to be match turnover rate, elasticity of
tendons, adapt to impact forces on ankles/knees/feet, and muscles need to
process energy efficiently. There's much more i'm sure.

Basically - the only way this would work is if it was paired with an
exoskeleton that would mitigate these issues to a large extent - for example,
almost no force required from legs, with minimal turnover - using a "leaping"
motion from the suit. So any fatso can move at a 4 min/mile.

Otherwise, all I could see this doing is possibly making an already highly
trained runner about 5-10% more efficient, but with zero military application
as a standalone. Soldiers typically carry about 50-60lbs of gear already, so
you'd be asking people to be highly trained runners with 50-60lbs of gear -
plus a jetpack - sounds like a recipe for face-planting and injury. You would
need an exoskeleton to manage the load. Then - this could get very
interesting.

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TrainedMonkey
I disagree with you about zero military applications. Imagine a backpack that
can engage thrusters to significantly reduce it's weight for a few minutes.
There is a significant difference to sprinting with 20 versus 120 pounds on
your back. Details are, as always, in execution. There are a host of
reliability, safety, and economic challenges to work out before this could get
anywhere.

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fasteo
I don´t think they have published any paper, but this kind of experiments are
tricky. In the setup showed in the video (n=1, not blinded[1], no control
group, no crossover), I would conclude that Jetpack does not work. The time
differences are small and the athlete is biased - unconsciously - to run
faster with Jetpack.

[1] Blinding in this case it not easy, but they can use a JetPack that sounds
like the real one, but does nothing.

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john_b
It seems like it's more of a feasibility demonstration at this point. Blinding
would be hard as you say, but if they could incorporate variable pitch blades
into the pack it should be doable.

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dangerlibrary
Alternatively, bikes. Folding bikes have been used for paratroopers and
military purposes for decades. And they can go much faster than a 4 minute
mile.

[http://en.wikipedia.org/wiki/Folding_bicycle](http://en.wikipedia.org/wiki/Folding_bicycle)

[http://en.wikipedia.org/wiki/Bicycle_infantry](http://en.wikipedia.org/wiki/Bicycle_infantry)

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spodek
It reminds me of an experiment some biologists did (sorry can't cite) to
demonstrate how wings could have evolved by showing how half a wing could
help. They cut short wings on flying bugs. The clipped bugs couldn't fly, but
they could move around a lot faster on water surfaces, which seemed a clear
advantage over walking speeds. You could imagine a leg evolving to act like a
half-wing to give that speed advantage, then you could imagine that leg
further evolving to a wing that could enable flight.

Designers and inventors can learn from this. When we want to make a huge jump,
like to a working jet pack for flying, it often helps to take small,
evolutionary steps.

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FrankenPC
It would be interesting to develop a vectored thrust inertia compensator.
Allow the troops to wear heavier armor but handle the load as if they aren't
wearing anything.

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guncheck
It would be really cool if they were able to eventually create exo suits
that'll let me do titalfall-like wall running :) Just cuz its really cool.

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iLoch
Exactly what I was thinking. Being able to apply force at different angles
would make for an interesting test for a project like this. Sure it can make
you run farther, but can it make you jump higher? What about prolonged ability
to run on a steep incline (either parallel or perpendicular to the slope)?
Once again it seems like the applications of this tech is dependent on energy
technology that may not exist yet. Where's my pocket fusion generator?

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agumonkey
It's like running with positive wind force.

ps: For flat surfaces I hope they made a test using some kind of rollerskates
/ shoe hybrid.

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Picard
That seems like it would work better actually, especially for long distances.

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JoeAltmaier
But fuel quickly becomes an obstacle - double the distance - double the weight
in fuel?

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GenerocUsername
Looked like battery packs to me. Basically just high powered fans pushing you
forward, not true jet-engines or rockets or anything.

That said, adding distance would require more batteries, and that would add
weight, but I would bet that the batteries are 1/10 the total weight with all
the metal-housing and motors involved

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JoeAltmaier
Batteries are about the least energy-per-kilo way of storing it - increasing
battery energy would cost the very most in weight you could imagine (except
perhaps a windup spring)

Liquid fuels (gas/alcohol) are very efficient. Metal-air batteries may beat
liquid fuels for ergs/kilo?

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Ryel
I think it would be interesting to see how this thing works for long distance
running if you could also extend the runners stride another 6 inches or more
through special shoes. Assuming that the key to efficiency by this machine is
to get the runner in the air for as long as possible and exert the least
amount of human energy.

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cliveowen
Well, it's not that impressive, it says the guy ran 3 seconds faster, how is
that useful in any context?

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k__
3 seconds saved on a 200 meters run. 18 seconds saved on a 1600 meters run.

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slipperyp
Right. It's a bit disappointing in the context of a page with the lead-in
"What if every soldier could run a four-minute mile?" but I trust this
research is still a work in progress and adding an 11lb weight + helmet and
taking those times off is a significant achievement.

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k__
It also sounded like the 11lb was the weight of the prototype. so when they
achieved the four-minute-mile they probably shrink it.

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discardorama
Imagine carrying that extra 11 pounds of weight around all the time, just for
occasional use in running. I don't think it's a good concept.

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Brashman
11 pounds is light by military standards.

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forgueam
Presumably this would be 11 pounds _on top_ of the existing load out, in which
case 11 extra pounds wouldn't be a trivial amount. Probably subjective though.

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bane
Not if the rest of the loadout is on a fully powered weight bearing
exoskeleton.

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seanflyon
In that case this system would have to be much more than 11 pounds to have
enough fuel and thrust for the added weight.

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qbrass
If it's self-supporting, it can weigh more because you're not limited by what
the soldier can carry.

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anigbrowl
'Enemy Jetpack hack causes spinal injuries'

