DARPA patent application
 

Re: DARPA patent application
 

and for those that have seen the videos, yes there is a reason this thing is called "The Benge Bungee"!!! :)

-dave

Re: DARPA patent application
 

w0w.. Talk about Aiming High!!
I hope this wasn't a secret project by DARPA, cause we all know when Dean's involved, people won't let the news of it just dwindle away into the night.

I am intrigued though about what does happen once you leave the chair.

Is there a part 2 invention to come later that helps slow yourself down??

The arc angles on the patent drawings didn't look like it would be too bad of a drop to fall from once you reached max height, but still.. a 5 story leap??? :ahh:

Re: DARPA patent application
 

In case anyone missed the related story (which better explains why this thread is in the forum it's in):

linkage

Re: DARPA patent application
 

Dave described this last year, so he can fill in details I may have forgotten. The device measures the height of the building, the distance from the base, and the weight of the "payload". It takes all that data and calculates the launch angle and velocity for a parabolic trajectory where the top of the building is the apex. At that point the "payload" has zero vertical velocity and very small horizontal velocity. In effect, you'd just take a leisurely step forward at the top.

Re: DARPA patent application
 

yes, but when it comes to tall buildings its not what happens at the top that matters, its what happens at the bottom

when you fall you experience normal forces until you hit the ground

if you are 'launched' to the top of the building, then you must experience high acceleration at the start of the ride. If the acceleration is too high out of the launcher you will black out (or snap your neck, or suffer internal damage...)

Re: DARPA patent application
 

Yeah, no sweat.

Let me get this straight...

Take that "leisurely step" after being shot 60-70 feet into the air, at the initial speed of about 65 ft/sec (19 m/s, 43 mph), travelling up to the top of the building in about 2 seconds. The cannon's launch would be similar to sitting in the driver's seat of a top fuel dragster pointed upward at about 80 degrees.

After this trip, a person might want to change their underpants.

AB

Re: DARPA patent application
 

take a step off of what?

I would think more along the lines of "Hope to God you land on your feet!"

and that there is something solid and nice to land on

like, a skylight, heat vent, or the open door to the stairwell :ahh:

this has Bugs Bunny/Road Runner physics written all over it! Where is Yosemity Sam when you need him "Shena Fratting NoGooden FreetaRotten No Good Varmit! I'll get you for this!" :^)

Re: DARPA patent application
 

What a great idea for 2007 FRC ! Call the new game "Just Shoot Me!" (or something similar -- I guess that name is taken by the TV sitcom.)

This would take the "Aim High" concept to new heights! A new level of challenge for the human player!

Of course, it would need to be extensively tested by the GDC, and might require a few new items in the kit of parts ... :D

[edit]... and a few more batteries. A rough estimate goes like this: to accelerate a 120# 'foolhardy payload' to 40 MPH exit velocity at 13 ft launcher height would require about 500 lbf thrust for about half a second. Assuming 50% conversion efficiency from the battery, you'd need about 40 kW electrical power during that split-second. Since our 12V batteries can only deliver about 200 peak amperes, you'd need about 16 of them to do the job.

And like Andy, I'd recommend a reserve set of underpants for the person who has just been accelerated at about 4g and then hurled five stories into the air![/edit]

Re: DARPA patent application
 

I particularly like the title at the top of the "related stories" list on the Register page:

Haha ... :p

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ok, but can it launch you with your segway onto the roof?

Re: DARPA patent application
 

The platform does look large enough to fit a Segway on it.

Maybe that's the secret to a smooth landing at the end?

Re: DARPA patent application
 

True, but I don't think the Segway will self-balance while flying through the air with the greatest of ease.

(Can someone with access to one verify that? :D)

Re: DARPA patent application
 

I'm not an engineer, but it seems to me that any attempt to use this with a living/delicate/explosive/etc. thing would be foolhardy, if the distance is long enough, any wind, poof, you're off course, then the calculations are invalid followed closely by splat. Then again, they may be compensating for that somehow...

Re: DARPA patent application
 

Nah, it works on compressed air. They'd just have to tweak the pnumatics rules.