Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pasteur!ucbvax!tut.cis.ohio-state.edu!osu-cis!att!cbnews!malloy@nprdc.navy.mil
From: malloy@nprdc.navy.mil (Sean Malloy)
Newsgroups: sci.military
Subject: Re: Update on USS Iowa
Message-ID: <5857@cbnews.ATT.COM>
Date: 24 Apr 89 02:57:41 GMT
References: <5795@cbnews.ATT.COM> <5839@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: Navy Personnel R&D Center, San Diego
Lines: 27
Approved: military@att.att.com



From: malloy@nprdc.navy.mil (Sean Malloy)

In article <5839@cbnews.ATT.COM> military@cbnews.ATT.COM (William B. Thacker) writes:
>[mod.note: The "/50" means that the length of the gun barrel is 50 calibers,
>i.e., 50x16" or 800 inches, long.  The longer the tube, the greater
>the velocity, and, therefore, range of the shell.  (The North
>Carolina and South Dakota classes which proceded the Iowas carried
>16"/45's, which were less effective)  - Bill ]

The barrel length has a much larger effect on the accuracy of the gun
than it does on the range; the barrel length allows a faster rotation
of the shell, which increases its stability in flight, which reduces
the amount it deviates. The contribution muzzle velocity makes on
accuracy is primarily due to the ability of using a flatter trajectory
for the same range, reducing the flight time that the shell is exposed
to wind and other causes of deviation. Compare the CEP of an antitank
gun with a howitzer at the same range and muzzle velocity -- the
longer barrel makes the AT gun more accurate.


 Sean Malloy					| "The proton absorbs a photon
 Navy Personnel Research & Development Center	| and emits two morons, a
 San Diego, CA 92152-6800			| lepton, a boson, and a
 malloy@nprdc.navy.mil				| boson's mate. Why did I ever
						| take high-energy physics?"