Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rutgers!att!cbnews!military
From: mmm@cup.portal.com
Newsgroups: sci.military
Subject: Sidewinder !!!
Message-ID: <12703@cbnews.ATT.COM>
Date: 2 Jan 90 02:48:14 GMT
Sender: military@cbnews.ATT.COM
Lines: 27
Approved: military@att.att.com



From: mmm@cup.portal.com
The article I recommended in an earlier posting had an odd technical error.
It had a picture of an early square-finned Sidewinder with three men standing
around looking at.  The caption said that the man on the left later invented
rollerons, which are a simple low-tech mechanism the Sidewinder uses to
inhibit rolling.

A rolleron is a metal disc with grooves near the edges so that it will spin
while the missile is flying (half of the disc is shrouded; half is exposed to
the airstream).  I surmise that they work like little gyroscopes, flexing the
tail fin on which they are mounted if the missile rotates too quickly along
the axis of its flight.  They resist the rolling motion by changing the 
aerodynamics.

Anyhow, the caption doesn't agree with the picture.  It says this guy LATER
invented rollerons, but if so he must have gotten the idea from looking
at the missile in the picture, which quite clearly has rollerons (they're
located on the tail fins, at the corner between the out-board edge and the
trailing edge).

What has me confused is the last photo in the article.  It shows a
Sidewinder being loaded on an F-16, and this missile seems NOT to have
any rollerons.  Could this be an air-to-ground version, or a version
for practice (the article said rollerons were only needed for stability
at high altitude)?