# Thread: The Physics Behind the Insanely Dangerous Japanese Water Jetpack

1. PopSci's Adam "Easy Joke" Weiner has worked out the physics of a super crazy Japanese water jetpack. Science is cool and all, but I just like watching this guy get tossed across a lake.

Essentially, this poor bastard left the launching pad at over 200 miles an hour due to the pressure of the water built up in the pack. It looks like he's using 25 two-liter bottles that tossed him about 80 to 100 feet. Unfortunately, he didn't calculate the rate of crap entering his pants during his flight, but maybe that's a job for a physicist with less scruples.

Japanese Water Jetpack
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japanese alligator prank
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2. Doc is not impressed with this jet pack concept. :mad:

3. Originally Posted by megimoo
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PopSci's Adam "Easy Joke" Weiner has worked out the physics of a super crazy Japanese water jetpack. Science is cool and all, but I just like watching this guy get tossed across a lake.

Essentially, this poor bastard left the launching pad at over 200 miles an hour due to the pressure of the water built up in the pack. It looks like he's using 25 two-liter bottles that tossed him about 80 to 100 feet. Unfortunately, he didn't calculate the rate of crap entering his pants during his flight, but maybe that's a job for a physicist with less scruples.

Japanese Water Jetpack
Mythbusters took this one on with the following results:

Bottle Rocket Blast-Off
The Build team attempt to recreate this Water Bottle Jetpack from a Japanese Game Show.

Myth statement Status Notes
According to a Japanese trivia game show, it is possible to use fifteen 3-liter sized water bottle rockets to launch a human 40 meters.

Results: Busted

While bottle rockets, on their own, could launch 1/15 of Kari's weight a fair distance, their combination into one super-rocket system did not have enough thrust to give the crash test dummy the trajectory or distance stated by the television show, and was considered too dangerous by paramedics to feasibly launch a human being. More bottle rockets proved only to add to the difficulty and complications. The Build Team also found that water cooler jugs, while able to launch higher at the standard air/water ratio for water bottle rockets, were weaker than standard soda bottles (which are designed to hold carbonated liquids), failing at around 60 psi (413 kPa) less than the soda bottles (90psi (600kPa) as opposed to 150psi (1000kPa)).

4. Originally Posted by Gingersnap
Doc is not impressed with this jet pack concept. :mad:
One step at a time you impatient wart!

5. Originally Posted by Goldwater
One step at a time you impatient wart!
This is simply unsuitable for Collies.

6. Or little Jap guys...:D

7. Originally Posted by Gingersnap
This is simply unsuitable for Collies.
Maybe Diet Coke + Mentos will provide enough boost .If your dogs were in the middle of that eruption they sure would be happy and in need of a bath !
Just like a 'sticky' fourth of July !
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This girl sure knows her way around condoms !
Condom Rocket Gone Wrong

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