SpudFiles

Ragnarok wrote:

jeepkahn wrote:I'll be running nO2

the muzzle velocity with a saboted golf ball will be just over mach 1, and 1200psi at about 1700fps....

Sorry, you'll not be going supersonic with Nitrous oxide (and why you even want to use Nitrous Oxide is a mystery) - it's too dense a gas to do that.

Assuming a mistake, and you mean Nitrogen - you might edge supersonic, but you're not going to 1700 fps. (If you're using GGDT, bear in mind, GGDT can give some pretty odd supersonic results, even to the extent that some velocities reported are actually physically impossible.)

My bad, nitrogen IS what I meant, and yes, I'm going on ggdt numbers(i guess i should've specified) Hopefully by the time I get it finished I'll have a chrony... What about helium, could I expect better with that??? a 40lb tank costs me $5 for nitrogen, and $15 for helium, these are refill prices, and an fyi, for those that have hipressure tanks, nitrogen is cheaper to refill than hpa, at least here where I am.......

Helium will be MUCH better. The less dense gas the better.

jeepkahn wrote:and yes, I'm going on ggdt numbers(i guess i should've specified)

In that case, you need to be wary about supersonic results. I've had results back that exceed the ultimate limits of a gas.

What about helium, could I expect better with that???

Definitely - where Nitrogen's speed of sound is about 1150 fps (and exceeding the speed of sound in your propellant gas is nigh on impossible), Helium's is around 3250 fps.
With helium, you probably will get close to the velocities predicted - and higher predictions as well. You might even manage to touch Mach 2 (in air) or more with enough pressure.

Do you already have a tank? they can get quite expensive.
@rag: nice sig =)

rp181 wrote:@rag: nice sig =)

Yes, it's a plan I have. Develop enough anti-Rickrolls and then bring them together with normal Rickrolls, causing both to disappear and release a huge amount of energy.

It'll be a source of clean and free energy for years to come.

Ragnarok wrote:

jeepkahn wrote:and yes, I'm going on ggdt numbers(i guess i should've specified)

In that case, you need to be wary about supersonic results. I've had results back that exceed the ultimate limits of a gas.

What about helium, could I expect better with that???

Definitely - where Nitrogen's speed of sound is about 1150 fps (and exceeding the speed of sound in your propellant gas is nigh on impossible), Helium's is around 3250 fps.
With helium, you probably will get close to the velocities predicted - and higher predictions as well. You might even manage to touch Mach 2 (in air) or more with enough pressure.

Cool, helium it is, and Airgas will lease me the tanks and regs for CHEAP!!!

Which brings me back to a hybrid. If it's supersonic you want or anything over that, you'll need to be considering a hybrid design or else use light gases. Also, the mass of your projectile will calculate heavily into whether supersonic is possible or not.

What is your planned source for 1200 psi N2O, air, nitrogen, whatever you decide on? By the time you procure all that you need, high pressure tanks, valves, gauges, hoses in the scale that you need it, you could have built an adequate and relatively low pressure hybrid a couple of times.

As helium is very expensive (compared to air) you could also consider to run a mix of helium/air.

@Ragnarok
How much mass does a rick roll have?
E = mc^2

I´m on my way constructing the most powerfull handheld , 2" bore piston pneumatics, running it at 300-500 psi.

To my knowledge at least.
2" porting piston valve, about 6' barrel

Not sure if I'll be brave enough to actually fire it at 500 psi , while holding it though.

Not with a redbull can full of concrete I ain't.... .sorry...me isn't

Me...not...(?)
Muhahaha

starman wrote:Which brings me back to a hybrid. If it's supersonic you want or anything over that, you'll need to be considering a hybrid design or else use light gases. Also, the mass of your projectile will calculate heavily into whether supersonic is possible or not.

What is your planned source for 1200 psi N2O, air, nitrogen, whatever you decide on? By the time you procure all that you need, high pressure tanks, valves, gauges, hoses in the scale that you need it, you could have built an adequate and relatively low pressure hybrid a couple of times.

If you'll go back a fw posts, you'll see that I will prolly be running He, and the Airgas shop down the road is run by a good customer of mine, he'll be less the equipment to me, and refills on a 40lb/18,000cu.ft. iirc, will be about 15 bux... this gun will be relatively simple, I'm building for these pressures so that i can keep the barrel length down to a minimum and still reach long range with heavier projectiles, and high fps with light ones...

I have lotsa friends that subsidize my habits, and that's the only thing making these projects feasible for me...

The lighter the gas is, the easier it is to go supersonic. Therefore hydrogen travels the quickest and is the best, and so on..

So heliums a good choice. When you upset little children you can blow them up floaty balloons that get stuck on the ceiling!

Good luck