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 :: 5 registered, 0 hidden and 62 guests


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

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Majestic-12 [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

"In the world of spuds today"

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

Unread postAuthor: MrCrowley » Tue May 08, 2012 5:07 am

The dart was actually a glass drill bit about 6mm in diameter, 'twas friggin' effective.

Video will come in ~24 hours, I want to see if I can do some more shots tomorrow/look for the dart and film its location relative to target.

Could it have struck the fence with minimal energy and just bounced off?
That's what i'm thinking as the sound is roughly 0.75s after the shot and the fence is roughly 20m behind the target. We're looking at sub-150fps for sure. I'm surprised the camera picked up the fence hitting sound and not it bouncing back on to the driveway if it didn't stick. Perhaps it landed on a small patch of dirt or the sound is actually a neighbour/my brother (who was painting down by the house) reacting to the sound of the shot dropping/hitting something.

edit:

The projectile penetrated all four layers of the target, which are spaced apart, with a perfect exit hole so I assume it was still stable in flight. But by my rough calculations, the projectile should have also collided with the driveway as my driveway slopes up relative to target location. My rough calculations had the projectile making contact with concrete ~1.5m from the fence; perhaps my estimate was off by that amount.
  • 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 » Tue May 08, 2012 6:25 am

How did you stabilise the drill bit?
  • 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 » Tue May 08, 2012 4:09 pm

It was supported in the barrel with a pusher and some cotton balls but in flight it might have been stabilised by the glass drill bit head; which is like a spade bit. Though it seems unlikely:
http://www.aquariacentral.com/forums/at ... 1329036840

Edit:

Went up and had a look, couldn't find anything. It's a real mystery where the sound came from.
  • 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 » Tue May 08, 2012 11:55 pm

MrCrowley wrote:cotton ball


Kiwi tech :)

Image

Y U NO USE PROPER SABOT?!

but in flight it might have been stabilised by the glass drill bit head; which is like a spade bit.


Only if the spade bit was at the rear...
  • 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 » Wed May 09, 2012 12:12 am

Y U NO USE PROPER SABOT?!
Well the pusher had a hole half way through which accommodated the rear section of the bolt after the fins (as seen here), the cotton balls were merely used as a means of keeping the bolt relatively centred in the barrel. Judging by the results, I think the sabot worked perfectly (I got a perfect entry hole from 20' indicating the bolt was flying straight).

Only if the spade bit was at the rear...
Really? I thought the spade at the front would be better aerodynamically than at the rear. Anyway, I think the projectile may have bounced off the concrete and hit the fence and then bouncing off again.
  • 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 » Wed May 09, 2012 12:23 am

MrCrowley wrote:Judging by the results, I think the sabot worked perfectly (I got a perfect entry hole from 20' indicating the bolt was flying straight).


We'll be the frickin' judges of that:D peeectures! videos!

Really? I thought the spade at the front would be better aerodynamically than at the rear. Anyway, I think the projectile may have bounced off the concrete and hit the fence and then bouncing off again.


Image

Image

The spade increases surface area, if it's pointing forward it moves the CP towards it, but likely does not make a corresponding difference in CG.
  • 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 » Wed May 09, 2012 12:50 am

jackssmirkingrevenge wrote:We'll be the frickin' judges of that[/b] [/url]:D peeectures! videos!
:D Uploading as we speak: ~137minutes

edit: 'tis live here:
[youtube]http://www.youtube.com/watch?v=xngrgaZzOL8[/youtube]
  • 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

Sponsored

Sponsor
 


Unread postAuthor: Labtecpower » Fri May 11, 2012 12:53 pm

I has tungsten!

Image

Now I need a sabot and I need to get my hybrid working again :D
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: Lockednloaded » Fri May 11, 2012 5:25 pm

Been doing some aesthetic work, nothing new as far as functionality goes, I need to work out a sleek loading system, and I have to wait for the arrival of my street elbow for a better chamber layout

Image
  • 0

I love lamp
User avatar
Lockednloaded
Major General
Major General
 
Posts: 1558
Joined: Thu Sep 03, 2009 9:38 pm
Location: Texas, USA
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Fri May 11, 2012 10:46 pm

Labtecpower wrote:Now I need a sabot and I need to get my hybrid working again :D


How had it stopped?

Looking pretty good there LnL!
  • 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: HunterT » Sat May 12, 2012 4:19 am

Labtecpower wrote:I has tungsten!

Image

Now I need a sabot and I need to get my hybrid working again :D


I fear that those tungsten electrodes(hopefully pure, not ceriated ) might be unstable in flight. What kind of of sabot will you be making?
  • 0

User avatar
HunterT
Staff Sergeant
Staff Sergeant
 
Posts: 113
Joined: Wed Jul 07, 2010 9:46 pm
Location: Just east of Russia
Reputation: 0

Unread postAuthor: Labtecpower » Sat May 12, 2012 2:13 pm

Image

Image

hybrid's working again :D

May have been caused by the cold or so..

and i'll have to look for a new backstop, 10 cms of newspaper and a cutting board were killed at only 7x

I'll only do short range shooting, not sure how i'm going to stabilize the welding rods yet.
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: DYI » Sat May 12, 2012 4:25 pm

and i'll have to look for a new backstop, 10 cms of newspaper and a cutting board were killed at only 7x


Unless you're trying to preserve your projectiles, low grade steel plate works fine as a backstop. I have a piece of 45mm plate which was presumably used as ballast in its past life for that purpose.

Concrete "patio stones" (slabs typically 30 - 60cm on a side and between 2 and 10 cm thick) also work well. If you have a box to toss them in, they also work after they're shattered...
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

Unread postAuthor: Labtecpower » Sat May 12, 2012 4:39 pm

ok pui...

Some preservation of my projectiles would be nice, so I'll get a steel plate with a thick layer of newspapers in front of it.
my launchers aren't strong enough to desintegrate teh projectile on impact, so that should be enough

thanks for your tip :)
  • 0

"ñøw mÿ šįg šüçkś!"
User avatar
Labtecpower
Major General
Major General
 
Posts: 1267
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: DYI » Thu May 17, 2012 10:33 am

ITWOST: A plumbing we will go...
  • 0

Attachments
Plumbing1Shrunk.jpg
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

PreviousNext

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Majestic-12 [Bot], Yahoo [Bot]

Reputation System ©'