Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 67 users online :: 4 registered, 0 hidden and 63 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

reaching the speed of sound (summer Project)

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

Unread postAuthor: huse_spud » Mon Jul 17, 2006 8:05 pm

that giant spudtech cannon has a 1.6:1 C:B ratio correct?

considering this, would it be more or less powerful if it had a say... 4:1 ratio?
  • 0

User avatar
huse_spud
1st Lieutenant
1st Lieutenant
 
Posts: 269
Joined: Sat Apr 15, 2006 6:52 pm
Location: Center Junction, IA
Reputation: 0

Unread postAuthor: boilingleadbath » Mon Jul 17, 2006 8:27 pm

Pneumatics, excluding lighter-than-air gasses, won't give you what you want.

You might try a steel cannon using hot steam and a burstdisk.
The GGDT can model steam-propelled projectiles... preliminary estimates show you can acheive the speed of sound using 600 psi of steam in a 7' long cannon (2' chamber, 5' barrel, both 2" diameter) using a 70g projectile (wooden sabot)

I'd build an extra-large cannon just to be sure of it.
Such a cannon could be built for under 100$.
Teflon is rated for operating at temperatures of 500*F - which is about the temperature you have to get your cannon to to generate 600 psi of steam.
I'm thinking a sheet-metal shroud around the chamber of your cannon, with a strip burner along the bottom.

I'd have to look up the derating factor for steel at such pressures, but I don't think it's too bad - and 2" pipe can almost certainly be used, as it's rated for over 1000 psi at room temp.

Just be careful, though... you can probably imagain the burns supersonic steam at 500*F would give one!
  • 0

User avatar
boilingleadbath
Moderator
Moderator
 
Posts: 1642
Joined: Sat Mar 12, 2005 10:35 pm
Location: Pennsylvania, USA
Reputation: 0

Unread postAuthor: Darkerweb12 » Tue Jul 18, 2006 11:22 am

I just had an epiphany, if you got some sort of temperature resistant burst disk, and filled the chamber 1/3 full with water, then got a few torches under the barrel, those would boil the water and produce steam enough to burst the disk.. just an idea
  • 0


Darkerweb12
Staff Sergeant
Staff Sergeant
 
Posts: 106
Joined: Sat Aug 20, 2005 10:03 pm
Location: Madison, Wisconsin
Reputation: 0

Unread postAuthor: Mihlrad » Tue Jul 18, 2006 4:36 pm

did this "epiphany" involve you learning to read the post above? You didnt think of that.
  • 0

User avatar
Mihlrad
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 467
Joined: Tue May 23, 2006 6:45 pm
Reputation: 0

Unread postAuthor: jerb » Tue Jul 18, 2006 9:00 pm

lol I was thinking the same thing but i dint want to say it.

also on a side note, I have decided (under your advice) to put off this project due to the dangers involved. Im going to make a few more pnuematics and maybe a cool combustion instead

if a mod reads this: this thread can be closed/locked
  • 0


jerb
Private
Private
 
Posts: 15
Joined: Mon May 01, 2006 4:25 pm
Reputation: 0

Unread postAuthor: Mihlrad » Tue Jul 18, 2006 10:57 pm

good to hear, we dont think you cant do it we are just looking out for your safety and keeping the good name of spudding good. Eventually you will be ready for it, but build up to it slowly. You do have a great piece of property for spudding though it seems. Good luck be sure to post what you make ^^
  • 0

User avatar
Mihlrad
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 467
Joined: Tue May 23, 2006 6:45 pm
Reputation: 0

Unread postAuthor: roderunner » Thu Sep 14, 2006 7:28 pm

I hate to tell you guys but you *cannot* break the sound barrier on compressed air alone.

Due to the laws of physics, air only travels at a certain speed. This is why the speed of sound is what it is. Even with near infinite pressure, the shock wave of pressure will only travel at the speed of sound. Thus unless one superheats* the compressed air, the potato will never exceed the speed of sound no matter what the pressure/volume of the compressed air is.

*As for superheating the air, that is what a combustion cannon does, and why the above does not apply to a combustion cannon.
  • 0


roderunner
Private
Private
 
Posts: 3
Joined: Thu Sep 14, 2006 7:22 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: jerb » Thu Sep 14, 2006 9:02 pm

hmph... way to necro a rather old thread.

also Im glad you chimed in, but is conisidered general knowlage that you cant break the sound barrier with compressed air, I beleive it may have been noted in this very thread (prior to your statement)
  • 0


jerb
Private
Private
 
Posts: 15
Joined: Mon May 01, 2006 4:25 pm
Reputation: 0

Previous

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'