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 20 users online :: 5 registered, 0 hidden and 15 guests


Most users ever online was 106 on Sat Jun 14, 2014 4:35 pm

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Most Efficient Projectile Shape

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
Sponsored 
  • Author
    Message

Unread postAuthor: salasd » Mon Jan 05, 2009 10:33 pm

the best shape i know of is called the sears hackbody, which looks like a cigar with pointed tips on each end. its best for areas around the super sonic speeds but i think its should be ok. somthing simpler though, golfballs
  • 0


salasd
Private
Private
 
Posts: 17
Joined: Mon Jan 05, 2009 9:26 pm
Reputation: 0

Unread postAuthor: Lentamentalisk » Tue Jan 06, 2009 12:54 am

Salasd, the closer observer would notice that golf balls have already been mentioned exactly 15 times in this article already (not counting quotes.) Before you post an obvious answer, check to make sure that answer hasn't been posted 15 times...
  • 0

Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
User avatar
Lentamentalisk
Brigadier General
Brigadier General
 
Posts: 1202
Joined: Tue Aug 07, 2007 5:27 pm
Location: Berkeley C.A.
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Fri Jan 21, 2011 2:44 pm

Interesting footnote to this from the wikipedia article on nosecones that Rag had linked to, an excel calculator that will design one for you, meant for model rocketeers but certainly applicable to spudgun projectiles for those seriously interested in long range.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 23940
Joined: Thu Mar 15, 2007 11:28 pm
Location: epoxy batcave
Reputation: 50

Unread postAuthor: Labtecpower » Fri Jan 21, 2011 3:42 pm

I looked back one page, and I saw rag talking about ice bullets.
(JFK kill theory)
What if they made a bullet out of bone, or frozen meat / gelatine / other body tissue? I think they would have better mechanical strength than just plain water, and aren't tracable.

Wat do you guys think about this?
  • 0

User avatar
Labtecpower
Major General
Major General
 
Posts: 1252
Joined: Sat Feb 20, 2010 6:38 am
Location: Herb Island
Reputation: 7

Unread postAuthor: Hotwired » Fri Jan 21, 2011 4:40 pm

Labtecpower wrote:I looked back one page, and I saw rag talking about ice bullets.
(JFK kill theory)
What if they made a bullet out of bone, or frozen meat / gelatine / other body tissue? I think they would have better mechanical strength than just plain water, and aren't tracable.

Wat do you guys think about this?


Firing bone or dead meat hasn't got much going for it aside from being rather grisly.

The untraceable bit of an ice bullet is that it melts and thus leaves no evidence. The practical side of making and firing one is another matter.

If you're going for something with mechanical strength you might as well go the whole hog and use metal, either way forensics have something to examine.
  • 0

User avatar
Hotwired
Lieutenant General
Lieutenant General
 
Posts: 2598
Joined: Fri Oct 13, 2006 5:51 am
Location: UK
Reputation: 0

Unread postAuthor: ramses » Fri Jan 21, 2011 5:10 pm

Now that this has been kicked up, I have to mention that no-one has talked about skin drag. Torpedoes achieve low(er) drag with cavitation. As long as the fins are out of the cavity, this shouldn't hurt stability.
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1676
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: ilovefire » Fri Jan 21, 2011 5:44 pm

Labtecpower wrote:I looked back one page, and I saw rag talking about ice bullets.
(JFK kill theory)
What if they made a bullet out of bone, or frozen meat / gelatine / other body tissue? I think they would have better mechanical strength than just plain water, and aren't tracable.

Wat do you guys think about this?


been tested by the myth busters with both frozen meat and ice, if i remember correctly the ice just turned to steam and the meat was more of a mince shotgun, both non lethal, altho they did only use firearms dont know how they would have gone in a air gun
  • 0

why make it if it dosent shoot?
User avatar
ilovefire
Colonel
Colonel
 
Posts: 511
Joined: Sat May 22, 2010 6:48 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: jackssmirkingrevenge » Sat Jan 22, 2011 12:58 am

ramses wrote:Now that this has been kicked up, I have to mention that no-one has talked about skin drag. Torpedoes achieve low(er) drag with cavitation. As long as the fins are out of the cavity, this shouldn't hurt stability.


wikipedia wrote:Supercavitation is the use of cavitation effects to create a large bubble of gas inside a liquid.


... so not really relevant to spudguns unless you've made a speargun ;) unless it's possible to create a vacuum bubble - but surely, if there were a simple way to do this, we would have seen in on military projectiles already?

Still, bloody hell!

[youtube]http://www.youtube.com/watch?v=h4tSRrMkYVg[/youtube]

On the subject though, one other drag-reducing concept not mentioned in this thread is the "base bleed" idea, though really if you're going to do that, might as well make a rocket assisted projecile.

(JFK kill theory)


Very interesting documentary including a detailled ballistic test showing the "single bullet theory" to be feasible, and talk of ice bullets to be a little silly ;)

[GVideo]http://video.google.com/videoplay?docid=-8673666872571189886#[/GVideo]
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 23940
Joined: Thu Mar 15, 2007 11:28 pm
Location: epoxy batcave
Reputation: 50

Unread postAuthor: POLAND_SPUD » Sat Jan 22, 2011 1:05 am

"base bleed" idea, though really if you're going to do that, might as well make a rocket assisted projecile.
that sounds feasible... well sort of
if you really want the max range possible you might turn the projectile into a steam rocket
  • 0

Children are the future

unless we stop them now
User avatar
POLAND_SPUD
Chief of Staff
Chief of Staff
 
Posts: 5389
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 7

Unread postAuthor: ramses » Sat Jan 22, 2011 11:15 am

Somewhere I read that you can also get air to cavitation. Perhaps I was mistaken.
  • 0

POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
User avatar
ramses
Major General
Major General
 
Posts: 1676
Joined: Thu May 29, 2008 6:50 pm
Reputation: 3

Unread postAuthor: Technician1002 » Sat Jan 22, 2011 11:31 am

You can. That is the cause of sonic booms. Supersonic flights result in areas in vacuum.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5186
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: saefroch » Sat Jan 22, 2011 6:43 pm

Technician1002 wrote:Supersonic flights result in areas in vacuum.
I assume you're talking about the rarefaction that travels behind the buildup of sound waves that occurs around the object. Certainly an interesting proposal, but to make significant use of that I'd think you need a significant sound source, which most aerodynamic projectiles do not create.

But still, isn't it possible to create a region of far lesser pressure with a specifically designed projectile?
  • 0

My First Effective Pneumatic - Aeolus's Trident
Current Project:Trident Mk. II

Machining is awesome.
User avatar
saefroch
Major General
Major General
 
Posts: 1678
Joined: Mon Jun 08, 2009 8:47 am
Location: U.S.A.- See Map
Reputation: 0

Previous

Return to Construction Materials/Ammo Discussion

Who is online

Registered users: Bing [Bot], crowbird, Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'