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 74 users online :: 4 registered, 0 hidden and 70 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

spudgun range, are we falling short?

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

Unread postAuthor: MrCrowley » Fri Apr 29, 2011 5:30 pm

Wow that's looking great! :)

An aluminium backplate shouldn't add too much weight I don't think. The thinnest aluminium you've got would do the job.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: al-xg » Fri Apr 29, 2011 5:37 pm

Even something like a cardboard disk would probably insulate it enough to prevent melting.

Plug diameter is 48mm, just a tad smaller than the bore, because the friction should came from the petals edge only.

How is the projectile sealed in the bore ?
  • 0

User avatar
al-xg
Colonel
Colonel
 
Posts: 643
Joined: Fri Jan 19, 2007 12:29 pm
Reputation: 0

Unread postAuthor: LeMaudit » Fri Apr 29, 2011 5:45 pm

MrCrowley wrote:Wow that's looking great! :)
An aluminium backplate shouldn't add too much weight I don't think. The thinnest aluminium you've got would do the job.


Yes, I will drill some holes in the UHMW, so the weight of the aluminum will not add much really. And a hole in the center will bolt the aluminum disk to the plug and will be used to support the petals just a bit with a custom thingy. I have to do something with those nice chicago bolts... You'll see :-D

I'm thinking that you could give a try to this sabot with a mockup MiniBoy first. Just too see if it open all right and the projectile fly strait. After all, the design is simple enough to be replicate without much effort and tooling by others for different projectile shape, so I think it worth some experiments. Of course I'll try to over-engineer it, but that's just me ;-)

Even something like a cardboard disk would probably insulate it enough to prevent melting.


Probably. But not as fun to do :lol:
  • 0

Last edited by LeMaudit on Fri Apr 29, 2011 6:31 pm, edited 1 time in total.
User avatar
LeMaudit
Donating Member
Donating Member
 
Posts: 665
Joined: Thu Apr 16, 2009 2:48 pm
Reputation: 0

Unread postAuthor: al-xg » Fri Apr 29, 2011 6:29 pm

Even something like a cardboard disk would probably insulate it enough to prevent melting.


Probably. But not as fun to do


In that case I would sat make your own honeycomb composite wad ;)
  • 0

User avatar
al-xg
Colonel
Colonel
 
Posts: 643
Joined: Fri Jan 19, 2007 12:29 pm
Reputation: 0

Unread postAuthor: LeMaudit » Fri Apr 29, 2011 6:33 pm

In that case I would sat make your own honeycomb composite wad


You know what? You might have something there :-D

Nah, seriously I'll just make a thin disk with a little recess that fit the UMMW, it will protect the edge from melting and also will add some rigidity.

I know, I know... :lol:
  • 0

User avatar
LeMaudit
Donating Member
Donating Member
 
Posts: 665
Joined: Thu Apr 16, 2009 2:48 pm
Reputation: 0

Unread postAuthor: MrCrowley » Fri Apr 29, 2011 6:43 pm

As for the mock-up testing, should I fire them from one of my pneumatic cannons? Less risk damaging the sabot and it will limit the range of the mock-up projectile.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: LeMaudit » Fri Apr 29, 2011 7:50 pm

Well, if the sabot is damaged, I guess it will mean that it didn't fire strait. The way it is made following JSR idea (again! :D ) should not put stress on the parts if they exit nicely from the barrel. And I can always make another one :lol: plenty of UHMW left.
I was thinking of a mockup ammo just not to loose the real shiny MiniBoy during testing :D

Are your other cannons made with the same bore 48.5mm? It could be a good idea to fire slow after all, to be able to see on slow-mo if the separation is done well.
  • 0

User avatar
LeMaudit
Donating Member
Donating Member
 
Posts: 665
Joined: Thu Apr 16, 2009 2:48 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: MrCrowley » Fri Apr 29, 2011 7:57 pm

Are your other cannons made with the same bore 48.5mm? It could be a good idea to fire slow after all, to be able to see on slow-mo if the separation is done well

No, but I should be able to swap the barrels on the launchers if I buy a 40mm x 50mm female x male threaded bushing. My 1.5" porting piston valve pneumatic has 2" barrel threads and so does my 2" sprinkler valve pneumatic.

I will also be able do slow-mo footage. If velocity was around 50m/s over a distance of 3m and I filmed at 420fps, I should get 30 frames of the projectile and sabot. Though I doubt 3m would be enough to catch the sabot falling away from the projectile. Perhaps 5m would do it?
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: jackssmirkingrevenge » Fri Apr 29, 2011 8:37 pm

Looking good! I'm confident you can shave off a lot of weight with some attention to the petals, drilling holes and bevelling and such - and as mentioned above the thinnest of ali plates should be enough as a backplate - polished of course ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: dewey-1 » Fri Apr 29, 2011 8:48 pm

What are the dimensions of the rectangles and plug thickness?

Why not use adhesive backed aluminum tape. It could be replaced easily enough or even double layered if required.
  • 0

User avatar
dewey-1
Major General
Major General
 
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Fri Apr 29, 2011 8:56 pm

MrCrowley wrote:I will also be able do slow-mo footage. If velocity was around 50m/s over a distance of 3m and I filmed at 420fps, I should get 30 frames of the projectile and sabot. Though I doubt 3m would be enough to catch the sabot falling away from the projectile. Perhaps 5m would do it?


You could also try filming down the barrel.

Why not use adhesive backed aluminum tape. It could be replaced easily enough or even double layered if required.


Sounds like a good idea, I'm confident that the design is supported enough to survive a reasonable mix without the need for a significant metal plate backing.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: MrCrowley » Fri Apr 29, 2011 8:58 pm

You could also try filming down the barrel

Ah, good idea :D


Just over a month on since the start of this topic (seemed longer), are you so far satisfied with the response and outcome, Jack? :wink:
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: jackssmirkingrevenge » Fri Apr 29, 2011 9:19 pm

MrCrowley wrote:Just over a month on since the start of this topic (seemed longer), are you so far satisfied with the response and outcome, Jack? :wink:


To be honest I expected a few interested replies but for the topic to fade within a week, so I'm amazed at the response.

Credit goes to everyone for brainstorming but in particular LeMaudit's fine machining is to be commended - though in some ways it has been counter productive, who on earth would want to fire such a work of art? Ah yes, you :P - and credit also to Duane for the detailed drawings of the whole proceedings.

I've also been privy to some similar projectile optimisation development work outside of the forum which has yielded fantastic results from what I've seen :) I really would like to see more of these sort of projects, they bring out the best of the forum and really it's what spudfiles should be about :D
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: MrCrowley » Fri Apr 29, 2011 9:52 pm

jackssmirkingrevenge wrote:I really would like to see more of these sort of projects, they bring out the best of the forum and really it's what spudfiles should be about :D

Well, you've got my vote for Mayor :wink:
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: jackssmirkingrevenge » Fri Apr 29, 2011 9:56 pm

Sorry for making it sound like a cheesy political party manifesto :P

Still, at least it wasn't passive agressive ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

PreviousNext

Return to General Spud Cannon Related

Who is online

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

Reputation System ©'