Speed Record

[cannon freak]

Could someone tell me what the highest speed any one has been able to shoot something.. By using some form of potato cannon wheather it be combustion, pnuematic, or a hybrid, Im guessing its a hybrid has the highest speed.

Any way I want to kow this beceause its going to be my summer project to build a sort of mini but not a huge hybird and I want to be able to break the record, it may or may not happen.

I also know that most people do not own a chronograph. But most people don't build guns that go mach 1

[CpTn_lAw]

Joel from spudtech beat the sound barrier...with a pneumatic. i broke the sound barrier too, with my mini penumatic from galvanized steel, and i shot a 6mm BB at 391 m/s. (barrel was perfect fit and a lentgh of 1m)

[benstern]

My pneumatic DOBA launcher when finished and equipted with a GB barrel can shoot golf balls at 2059 feet per second while the spped of sound would be 1162.875 feet per second

however if the barrel is increased to 370 inches the speed would be over mach 2! 2344 ft/s!!!

[noname]

That's just crazy. That's means you would get a mile in 2 seconds. Jesus I'm glad I don't live near you.

[cannon freak]

Benstern are you planning on using helium or another gas in your gun? Beceause if you just used normal air it could not go mach 1. I learned of this little fact in one of my first post when I was wondering how to go supersonic. Its just not possible for air to move a projectile that fast.

Now if you are using another gas than it is could be possible

So are you using helium?

[Velocity]

That's just crazy. That's means you would get a mile in 2 seconds. Jesus I'm glad I don't live near you.

not necessarily. That is just muzzle velocity. It will definitly slow down a very significant amount as soon as it leaves the barrel. But yeah, it would go far.

Benstern, how exactly are you planning on making a golf ball go that fast?

[benstern]

No actually I will use Hydrogen. It is the ultimate gas for pneumatics.
How to make it go fast: build a big launcher!!!
http://rapidshare.de/files/24109775/sup ... l.gdt.html

[cannon freak]

Holy crap man thats going to take forever to fill up, unless you are buying the gas. Again, holy crap you better be carfull with that fuel even if the hydrogen can not react with oxygen in the tank, if there is a leak and an ignition sourcs then bye bye launcher.

[crcowboyfan]

How do i open the .gdt file?

[benstern]

save to disk, then open it with GGDT.

[frogy]

Could someone tell me what the highest speed any one has been able to shoot something.. By using some form of potato cannon wheather it be combustion, pnuematic, or a hybrid, Im guessing its a hybrid has the highest speed.

Any way I want to kow this beceause its going to be my summer project to build a sort of mini but not a huge hybird and I want to be able to break the record, it may or may not happen.

I also know that most people do not own a chronograph. But most people don't build guns that go mach 1

Joel of http://www.SpudTech.com shot a potato over Mach 1 with one of his guns, he had to be over 1000 fps if he shot from his house according to a Speed\Mach calculator....

[boilingleadbath]

Many acctualy doubt he got supersonic velocities. It's a fairly short launcher that supposedly fired a reasonably massed projectile using pressurized air.

Any 2 of those in conjunction make it almost impossible to get such velocities, and the GGDT doesn't coincide with his claim at all.

[benstern]

had to be over 1000 fps if he shot from his house according to a Speed\Mach calculator....

You do know that the speed of sound in air is dependent on temperature not altitude?

In theory if I fired a 0.5 gram projectile 2.25" in diameter from my DOBA launcher equipped with a 80" barrel it could attain a speed of 8974 feet per second.

"WTF would weigh 0.5 grams and be 2.25" in diameter" you ask?
Why an aerogel does!

Aerogels are composed of 90-99.8% air with typical densities of 3-150 mg/cm3.

from http://en.wikipedia.org/wiki/Aerogel

EDIT: that would be mach 7.717 at 100 degrees fahrenheit

[frogy]

Well in Appleton, Wisconsin with about a 150 gram potato 2", with a Supah Valve and a big ass air chamber to 100+ psi hydrogen, he could break it easily...

Even with helium or compressed air... What are you talking about relatively small? The chambers like 8 ft of 5" from the looks of it, and the barrel looks like 15' of 2"

[benstern]

Actually three 3" five foot long SCH-80 pipes for chambers. Only 100 pounds