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 66 users online :: 3 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], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Diabolo Projectiles in Un-rifled Barrels: Do They Work Well?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Diabolo Projectiles in Un-rifled Barrels: Do They Work Well?

Unread postAuthor: danielrowell » Sun Sep 18, 2011 8:05 pm

I've been curious about this for a while now. Has anybody ever tried launching a diabolo-type projectile from a cannon with an un-rifled barrel and, if so, did it fly without tumbling?

Diabolo projectiles have a pinched waist and a higher weight bias in the nose. The high air resistance on the back of the projectile is supposed to prevent it from tumbling. Pellet guns commonly shoot diabolo pellets since their rifling isn't as effective in stabilizing the projectile as it is in conventional rifles, and the diabolo style is supposed to be reasonably effective in smoothbore guns.
  • 0

User avatar
danielrowell
Sergeant
Sergeant
 
Posts: 89
Joined: Sat Sep 10, 2011 9:46 pm
Reputation: 0

Unread postAuthor: saefroch » Sun Sep 18, 2011 8:19 pm

In theory it should stabilize if the skirt is fitted to the barrel ID. However, finned designs or those with a different tail material tend to be a better bet for a smoothbore.
  • 0

User avatar
saefroch
Major General
Major General
 
Posts: 1679
Joined: Mon Jun 08, 2009 8:47 am
Location: U.S.A.- See Map
Country: United States (us)
Reputation: 0

Unread postAuthor: danielrowell » Sun Sep 18, 2011 8:23 pm

Oh...Now I feel kinda dumb for asking. :oops:
  • 0

User avatar
danielrowell
Sergeant
Sergeant
 
Posts: 89
Joined: Sat Sep 10, 2011 9:46 pm
Reputation: 0

Unread postAuthor: Moonbogg » Sun Sep 18, 2011 8:30 pm

Sureshot sells them (plastic spudgun pellets with metal noses) and yes they work very good.
  • 0

User avatar
Moonbogg
Major General
Major General
 
Posts: 1375
Joined: Mon Oct 13, 2008 10:20 pm
Location: whittier, CA USA
Reputation: 0

Unread postAuthor: Gippeto » Sun Sep 18, 2011 9:47 pm

Only made the one to prove a point...it punched a round hole though. :D

My thinking is that the diablo slug IS slightly better for smooth bore airguns than the foster slug. Less drag in the barrel, and the skirt obdurates easier to seal the bore.

Greater angle exposed to airflow should also increase stabilization forces...minimizing "wobble" and working well over a broader velocity range.

BUT....having made both types...the foster slug is a heck of a lot simpler to make an effective mold for.
  • 0

Attachments
Slugs.jpg
"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2393
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: jackssmirkingrevenge » Mon Sep 19, 2011 12:21 am

Dr. Beeman wrote:The diabolo shape of modern airgun pellets was developed empirically early in the 20th century. The key reason was the simple matter of greatly reducing friction in guns which had so much lower power than firearms. The diabolo pellet has the minimally required two stabilization points, fore and aft, but no friction between them.

Concomitant with this was the concentration of weight in the head which is a trick used by the developers of many other projectiles: sabots, "mini-balls"., lawn darts, badminton shuttlecocks, etc. to stabilize the flight of the projectile.

And, as a very large bonus, perhaps realized at time, was having a thin skirt which would be expanded, even by the relatively weak blast of gas from an airgun, to nicely seal the projectile into bores of such widely divergent sizes as those of German and English airguns of the supposedly same caliber.
  • 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

Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'