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 68 users online :: 5 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], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Pressure question

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

Unread postAuthor: velocity3x » Sun Feb 14, 2010 8:31 pm

Gun Freak wrote:
You missed the unquote by the way.


Yes I did but..... I did get the pressure / force question correct. :lol:
  • 0

User avatar
velocity3x
Brigadier General
Brigadier General
 
Posts: 827
Joined: Fri Jun 05, 2009 3:09 pm
Location: Yuma, Arizona
Country: United States (us)
Reputation: 7

Unread postAuthor: Davidvaini » Sun Feb 14, 2010 8:45 pm

make sure you run GGDT as administrator..sometimes that error will come up if you dont.

and if you cant run it as administrator, ask your parents for permission.
  • 0

User avatar
Davidvaini
Major General
Major General
 
Posts: 1315
Joined: Tue May 29, 2007 8:58 pm
Reputation: 0

Unread postAuthor: Gun Freak » Sun Feb 14, 2010 9:16 pm

We all have administrative privledges or whatever.
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: btrettel » Sun Feb 14, 2010 10:55 pm

Gun Freak, have you tried my suggestion? The thread below I believe contains the relevant information. If not, try the other ones that come up in the search I mentioned.

http://www.spudfiles.com/spudtech_archi ... f=1&t=3154
  • 0

All spud gun related projects are currently on hold.

btrettel
Major
Major
 
Posts: 380
Joined: Sun Feb 03, 2008 4:40 pm
Location: Maryland
Reputation: 0

Unread postAuthor: D_Hall » Mon Feb 15, 2010 12:43 am

Davidvaini wrote:It is the premiere tool for gas gun design.

To be fair, I think it's more accurate to simply refer to it as the most popular.

Jimmy101 and Btrettel both put out codes that are every bit as good as GGDT(*). And I believe they're open source for those who want to look at the guts of such programs.




(*) And possibly better for transonic. I know Btrettel is workign that issue harder than I did when I was writing GGDT. Although I'm prepping for a full rewrite... ;)
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

Unread postAuthor: velocity3x » Mon Feb 15, 2010 7:50 am

D_Hall wrote: Although I'm prepping for a full rewrite... ;)


D_Hall
I recently had use of some radar equipment and operators. For laughs, they tracked my golf ball cannon. I fired 5 shots ranging from 685-1194.22 fps. I entered the firing psi into GGDT after each shot and GGDT predicted the velocity to be only 3-7 fps slower than the actual shot. If GGDT has a problem.... it wasn't apparent in my tests.
  • 0

User avatar
velocity3x
Brigadier General
Brigadier General
 
Posts: 827
Joined: Fri Jun 05, 2009 3:09 pm
Location: Yuma, Arizona
Country: United States (us)
Reputation: 7

Unread postAuthor: CpTn_lAw » Mon Feb 15, 2010 8:04 am

Yup, you did a great job writing those programs D_Hall. HGDT works great , GGDT works great. What language did you write it in?
  • 0

"J'mets mes pieds où j'veux, et c'est souvent dans la gueule."
User avatar
CpTn_lAw
Brigadier General
Brigadier General
 
Posts: 987
Joined: Sun Sep 11, 2005 9:10 am
Location: France
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Gun Freak » Mon Feb 15, 2010 11:19 am

btrettel wrote:Gun Freak, have you tried my suggestion? The thread below I believe contains the relevant information. If not, try the other ones that come up in the search I mentioned.

http://www.spudfiles.com/spudtech_archi ... f=1&t=3154


I did everything they said to do on that thread except the one about right clicking on the ini file. Where is that file? It's not in the GGDT folder for me.
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: CpTn_lAw » Mon Feb 15, 2010 12:38 pm

Right click ==> Run in compatibility mode ==> windows vista.
  • 0

"J'mets mes pieds où j'veux, et c'est souvent dans la gueule."
User avatar
CpTn_lAw
Brigadier General
Brigadier General
 
Posts: 987
Joined: Sun Sep 11, 2005 9:10 am
Location: France
Reputation: 0

Unread postAuthor: Gun Freak » Mon Feb 15, 2010 1:50 pm

I got it to run... finally. What does "barrel choking flow" mean?
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: D_Hall » Mon Feb 15, 2010 2:41 pm

Gun Freak wrote:I got it to run... finally. What does "barrel choking flow" mean?

It means that the choke point in your flow isn't in the valve (which is often the case), but rather in the breech of your barrel. This is actually a good thing, but it also means that upgrading your valve will not result in better performance.



edit(s)....

@Velocity: Thanks. It's rare to get reliable feedback.

@Cptn: Again, thanks. I wrote it in Visual Basic 6.0 but don't imagine for a second that was my preferred language. It just happened to be the development environment I had lying around so I used it. Historically, I'm an ANSI C guy (I loooove C). So I've purchased MS Developer's Studio 2008 (which includes Visual C++). I've not a lot of experience with non-ANSI compliant C so there'll definitely be a learning curve, but there are so many things that I would like to do with the code that I simply don't know how to do in Visual Basic but would be trivial to do in C.
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

Unread postAuthor: Gun Freak » Mon Feb 15, 2010 8:01 pm

D_Hall wrote:but rather in the breech of your barrel.


My barrel does not have a breech, it is a co-ax.
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: Ragnarok » Mon Feb 15, 2010 8:12 pm

Gun Freak wrote:My barrel does not have a breech

So it's a barrel with only one end?

In this sense, breech is being used as a term for the non-muzzle end of the barrel. It might typically refer to breech loading, but what else would you call "the other end of the barrel"?
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Unread postAuthor: Gun Freak » Mon Feb 15, 2010 8:41 pm

So is it being choked because the ammo or what?
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: D_Hall » Mon Feb 15, 2010 10:04 pm

Gun Freak wrote:So is it being choked because the ammo or what?

It's being choked because that's where the flow chokes. That's what fluids do in non-trivial pressure differential driven flows; they choke.

Beyond that, I'm not sure what to say... You haven't the education to understand the explanation. Or perhaps I'm a bad teacher. Anybody got a super-basic explanation for the concept of choked flow?
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

PreviousNext

Return to General Spud Cannon Related

Who is online

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

Reputation System ©'