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spudgun range, are we falling short?

A place to ask general spud cannon related questions.
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Unread postAuthor: Lockednloaded » Mon May 23, 2011 2:26 pm

New pengun ammo? :lol:
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Unread postAuthor: LeMaudit » Mon May 23, 2011 2:28 pm

Lockednloaded wrote:New pengun ammo? :lol:


Geez... I didn't thought about that... now JSR will FAP again :?
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Unread postAuthor: jackssmirkingrevenge » Mon May 23, 2011 2:53 pm

LeMaudit wrote:Geez... I didn't thought about that... now JSR will FAP again :?


No.

But now you have to make a nano-boy for a future project ;)
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Unread postAuthor: LeMaudit » Mon May 23, 2011 3:11 pm

No.

Fair enough. Never abuse good things...

But now you have to make a nano-boy for a future project

Well, this retrorocket was collecting dust... It's about 4mm diameter, a tad smaller than a BB pellet.... I could fire it :D
Anyone know a nice <s>bïtch</s> beach?

Making a little mold for miniature lead ammo would also have some appeal :lol:

I already have some brass casing:

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Unread postAuthor: jackssmirkingrevenge » Mon May 23, 2011 3:16 pm

LeMaudit wrote:I already have some brass casing


:shock:

MUST HAVE LATHE AAAAGH!!!!!
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Unread postAuthor: irisher » Wed Jun 01, 2011 9:43 pm

Bump

After a little bit of penetration testing, I have decided to fire my custom made round for distance. The problem I am having is that I do not know how to calculate the drag coefficient. I thought you guys might be able to help. The rod is 3/8" in diameter by 10" long with 3, 2.5" by .75" fins welded on to it. I realize the probability of recovery is very low but a drag estimate would be useful. If you need any more information, let me know.Image
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Unread postAuthor: jackssmirkingrevenge » Wed Jun 01, 2011 11:53 pm

A bit difficult to calculate, is usually determined experimentally.

Looks like it will go far though, what are you shooting it out of? And what does the sabot look like?

You could make your own wind tunnel, this is from 1942 - when men were men and carved their own propellors!

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Unread postAuthor: MrCrowley » Thu Jun 02, 2011 12:05 am

Isn't irisher's projectile too tail heavy?
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Unread postAuthor: jackssmirkingrevenge » Thu Jun 02, 2011 12:38 am

MrCrowley wrote:Isn't irisher's projectile too tail heavy?


... but the fins are pretty huge so the centre of pressure is very far back.
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Unread postAuthor: irisher » Thu Jun 02, 2011 7:15 am

I actually thought it would never work after I measured center of gravity but I have had great success with this round. The sabot system is short dowel wrapped in duct tape as the pusher plate and carved Styrofoam as the guides. I am firing this thing out of my 1.5" sprinkler gun.
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Unread postAuthor: jackssmirkingrevenge » Thu Jun 02, 2011 7:49 am

irisher wrote:I have had great success with this round.


Videos/photos please!
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Unread postAuthor: dewey-1 » Thu Jun 02, 2011 12:03 pm

Here is the CP based on 1/8" thick fins.
The CG should be at least one caliber 3/8" ahead of CP.

irisher, where is the actual CG?
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Unread postAuthor: irisher » Thu Jun 02, 2011 3:43 pm

The center of gravity is exactly 6" from the tip. I made some holes in 1/8" plate steel but the fins never actually get through. It will bury itself approximately 5.5" into solid wood and is quite annoying to get out.
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Unread postAuthor: jackssmirkingrevenge » Thu Apr 19, 2012 12:36 am

Just over a year since this thread was started and not that much progress :)

MrC, what are the chances of fitting a smaller calibre (25-35mm) barrel to your hybrid? If you could shoot stuff with those dimensions I could perhaps cook up some less elaborate projectiles with relative ease, something that would be more likely to be fired and it would not be a tragedy if they were never found.
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Unread postAuthor: MrCrowley » Thu Apr 19, 2012 12:59 am

Shouldn't be too difficult, I have some ~25mm iron pipe in the garage although it does have a seam running its length. I wonder if it would be best used on my smaller burst disk hybrid: faster opening time and convenience vs. greater flow and larger chamber volume.
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