LRC-150 Mobile Spud Assault Unit

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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mark.f
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Wed Jun 20, 2007 9:36 pm

VH_man wrote: MarkHFq: remember that GGDT does not take into account the fluid dynamics involved in the flying projectile. the golf ball has little divits that technically should give it a backspin, causing longer range. thats why golfers can hit the ball so far. its not because they hit it really hard, its because of the backspin.......... i can hit 250 yards without putting ANY power into the club (well some, but alot less than i can do)....
The golfball gets longer range because this action creates a lower drag, meaning a lower drag coefficient. A Cd of .5 is a perfect sphere or smooth cylinder, so I chose something a little lower to simulate a golfball.
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Billy Bob
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Sat Jun 23, 2007 4:05 am

I like that spudgun very nice !!! :D
e1337
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Mon Jun 25, 2007 3:15 pm

That thing is a beast! Wow...
Scotty
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Wed Jun 27, 2007 10:06 pm

I am going to start making a list of people who make ridiculous range claims.[/quote]

That's the best idea i've heard all day, it seems some people like to live in fantasy land!!

Peace
Scotty
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sk8er548
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Tue Jul 10, 2007 10:48 am

Man you got a quad and i've only got a skateboard
Pedal to the Metal,
Jesus didn't Were Shoes,
Don't do Acid
sk8er ;)
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Binder17
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Mon Jul 08, 2013 9:09 pm

So this is really old but Mark.F. and I finally got a more accurate measurement of the muzzle velocity (originally estimated at 580 fps). Mark.F. built a basic chronograph and we did several shots at different pressures and got a consistent reading of 830 fps. In a vacuum, it will go about four miles, provided it travels in a straight arc at 45 degrees. Factor in air resistance and junk, I think it is safe to say it will achieve a half mile.
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Binder17
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Mon Jul 08, 2013 9:15 pm

Here is the updated design. Same design but different aesthetically.[/img]
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mark.f
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Mon Jul 08, 2013 10:36 pm

Using both GGDT's built-in range calculator and a quadratic air drag model with a generous drag coefficient (in excel using a 10ms time step) I get a range of about 1000 to 1300 feet (under 400 meters or 1/4 mile). Still pretty respectable.
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