[Beowulf] Re: "hobbyists"

Jim Lux James.P.Lux at jpl.nasa.gov
Tue Jun 24 09:25:19 PDT 2008

At 02:31 PM 6/20/2008, Peter St. John wrote:
>The destructive radius of Little Boy was about total, up to about 
>one mile radius, and tapered down to light at about two miles. So 
>being in a lead-lined steel container at 2000 meters might be OK for Indiana.
>In all action movies, blasts throw people unhurt for long distances; 
>when that much force (to impart that much momentum) would kill you. 
>That part is just conventional Hollywood. I could teach RGB to kick 
>me so that I fly through the air as in a Bruce Lee movie; it's a 
>stunt, and real kicks reallly hitting drop you like a sack of 
>potatoes, I've seen it. But not in movies. Similarly bullets, they 
>drill holes in you, if they pushed you through the air the recoil 
>would do the same to the shooter.
>As for the scene's good taste I can't say, I haven't seen the movie yet :-)

As someone who used to work in the business of doing this sort of 
thing (e.g. physical effects) for movies, TV shows, and commercials, 
you can assume that whatever you see on screen is specifically 
designed to "look like" what the director thinks will create the 
correct impression in the viewer. (e.g. real rain is invisible on 
film, for all intents and purposes..)

For blasts (or kicks, etc.) flinging folks about, they use what is 
known as a "jerk vest" (for the high third derivative of position, 
not to describe the wearer) and bungee cords, springs, hydraulic 
winches, etc.  Note well that the effects tech just runs the gear.  A 
stunt person (aka human sandbag) survives the loads (and gives thanks 
to Stapp).

To fling things about, we used a variety of things.. air power is 
popular, so is gunpowder. (look under a car that flips over for the 
piece of telephone pole used as the piston in a one-shot internal 
combustion engine.)  Speaking of refrigerators, air pressure is just 
fine for a hundred meter or so launch.

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