We at BUNGCO are pissed off at paintball guns. You drop $500 on a gun, then need to buy expensive cartridges and for what? Puny bang bang? How many times can you peg a guy before he yells "hit"? Three? We set out to build a better way.
A $150 Stihl gas powered leaf blower has a muzzle velocity of 200 mph - comparable to the 300 feet/second of the average paintball. Note however that the leaf blower muzzle diameter is nearly ten times that of the paintball gun. The Stihl motor had trouble with a muzzle one tenth the size, but a third the size worked well, with corresponding threefold increase in wind velocty. All that remained was the hopper - essentially pouring the balls down into the windstream. The hopper must be huge, to accomodate the firehose-like stream of balls produced.
All the money saved on cheesy paintball guns and CO2 cartridges can now be spent on balls balls balls. Then more balls! Sure its loud and makes a lot of smoke, but that is true for many scary things.-- bungston, Jun 20 2006 "Halt! who blows there?" "Just like a BUNGCO rep. to bring a leaf blower to a cannon fight."
<ktssssssssssssssssssss!>-- 2 fries shy of a happy meal, Jun 20 2006 Coming soon, the CO2 cartridge leaf-blower.-- AbsintheWithoutLeave, Jun 20 2006 /mini-gun version/ - that actually might work well. The spinning chamber part could move up, receive the ball then rotate down into the wind to release it.-- bungston, Jun 20 2006 When and where is the BUNGCO IPO?
Hold that thought... 300 ft/sec is roughly 205.7 mph. Ah, diameter reduction in the pipe. Never mind, as you where.-- methinksnot, Jun 20 2006 I dont know it this counts as slightly baked or not, but i have seen leaf blowers converted to aid in rolling or "t.p."-ing a house with a wire attachment placed over the muzzle, holding a roll of toilet paper in a manner so as to allow it to shoot a stream of tissue 15-20 feet in the air. very effective for mild mannered vandalism by teens and church youth groups across the world, but you must use an electric leaf blower so as not to wake everyone within a 3 mile radius.-- Hunter79764, Jun 21 2006 Lucky you would have the money for more balls, since stealth would no longer be an option. (Unless everyone is wearing ear-protectors).-- trekbody, Jun 26 2006 Have you actually built one? even at 1/3 diameter, the barrel must be many times the diameter of a paintball. Therefore you are injecting paintballs into a high-velocity airstream. How long is your barrel? And more importantly, have the paintballs accelerated to match the airspeed by the time they leave the muzzle? Even close?
a few simple calcs, even if you're only kicking out paintballs at 300fps: V(projectile) = 100m/s (ish) ~ 300fps
with a 1m barrel, this is 5000m/(s)^2 acceleration, assuming it's constant (the numbers get worse if it isn't)
guestimating a 10 gram projectile, we get a force of 50N
With a 0.5" diameter ball, this means a cross sectional area of about 5X10^(-4) metres squared.
giving a required pressure drop of about one atmosphere. (F=PXA)
You have a supersonic airstream? Can I have one of those leafblowers?
This doesn't even take into account compressible airstreams, so is very conservative.
I say again, have you actually made one?
Oh yeah, you say a threefold increase in air velocity : up to 900FPS?
Um, that's getting pretty close to transonic speeds. Good luck. I say again, can I have one of these leafblowers?
(-)-- Custardguts, Jun 27 2006 Does a pressure difference of 1 atmosphere make a supersonic airstream? You lost me at that step, [guts]. But I am happy to learn.
As regards actually building something, that would require getting up from my armchair. I am a pure theoretician. Pure as the driven snow.-- bungston, Jun 27 2006 Well, that was my words, from what I remember of aerodynamics. It's not ever written like that, but in order to get that pressure drop in an open stream, you need supersonic-like airflow. We're making big assumptions here, but I assume that the gauge pressure isn't much above atmospheric in the barrel.. Hey, I'm just a mech eng, but the aeronautical eng sitting over to my right had a read through, and said that I oversimplified it, but was basically right.
If however you aim for lower velocities and/or a longer barrel, you might get it to work. Kinda.
Sorry, I completely ignored the fact that it was you, [bung] and read the idea as if you were saying you'd made one. as for ideas, it's top-notch, just needed a little reality, that's all.
I'd remove the bone if I knew how, given that this was an idea, not a claim to have made one. I think I'm taking myself a little too seriously today :(-- Custardguts, Jun 27 2006 random, halfbakery