sabot rounds

28 August 2002, 17:58

BBBruce

sabot rounds

I've been told that military sabot tank rounds increase substantially in velocity when the wrapper falls away. A physics expert attributed it to something he calls "conservation of momentum," meaning that once a projectile starts moving and mass falls away, the momentum is conserved and converts into more velocity in the forward moving projectile. Question: does anybody have experience with small arms sabots? Does the same thing happen?

29 August 2002, 04:01

scot

quote:
Originally posted by BBBruce:
I've been told that military sabot tank rounds increase substantially in velocity when the wrapper falls away. A physics expert attributed it to something he calls "conservation of momentum," meaning that once a projectile starts moving and mass falls away, the momentum is conserved and converts into more velocity in the forward moving projectile. Question: does anybody have experience with small arms sabots? Does the same thing happen?

29 August 2002, 04:03

scot

No, doesn't happen with the tank round either. The velocity of the projectile will not increase unless energy in put into it. Your physics professor did not understand the question. The conservation of energy is a basic tennant of physics.

29 August 2002, 04:58

ricciardelli

Your "physics expert" is all wet.....

29 August 2002, 05:58

waitaminit

The projectile = (light) wrapper plus (heavy) bullet has a very poor BC which improves dramatically when the wrapper goes its own way.

When the kinetic energy of the bullet remains and the BC increases, to my understanding bullet velocity will rise.

Accuracy will not be mostly poor as the separation of the two components provides a "kick" to the bullet.

I wonder how the bullet's twist will develop.

[ 08-28-2002, 21:07: Message edited by: waitaminit ]

29 August 2002, 06:07

<chevota>

waitaminit:

Yer killin me

29 August 2002, 07:32

waitaminit

"to my understanding bullet velocity will rise."

ooops - what I mean is:
due to lower drag, loss of velocity will decrease and trajectory will be flatter. - Velocity relative to the combined projectile's theoretical further path is higher.

As long as there is no extra force added, there is no absolute rise in verlocity.

Sorry for the incorrect statement.

29 August 2002, 09:18

<eldeguello>

waitaminit, yore last explanation is the correct one!! The projectile will begin losing velocity at a lower rate after the sabot is discarded; this effect would also be present in a small-arm round also. In the case of tank main-gun ammo, there's no rotation of the projectile, because the gun is a smooth-bore. [Big Grin]

29 August 2002, 17:42

BBBruce

quote:
Originally posted by eldeguello:
waitaminit, yore last explanation is the correct one!! The projectile will begin losing velocity at a lower rate after the sabot is discarded; this effect would also be present in a small-arm round also. In the case of tank main-gun ammo, there's no rotation of the projectile, because the gun is a smooth-bore.

Answers make sense. Thanks !!!!!!!!!!

29 August 2002, 20:59

waitaminit

I forgot it's a tank gun discussion.
Two weeks ago I had some .30-06 sabots fired through a PACT: 4200 fps - I was a bit disappointed.

That's why I'm wondering how twist will develop.

And when will the sabot split away from the .223-bullet ? - I read something about 30 something and tend to believe it's inches and not yards.

30 August 2002, 03:28

Clement

Waitaminit's last explination was correct. However there is rotation on tank fired sabot rounds. The sabot has stabilizing fins that impart a spin on the projectile. The gun is a smoothbore because with a muzzel velocity of 5000+ fps rifling bands on the sabot sleeve would not be able to engage, they would get pushed over the rifling, or something like that.
Dave