Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!att!cbnewsc!cbnews!cbnews!military
From: cga66@ihlpy.att.com (Patrick V Kauffold)
Newsgroups: sci.military
Subject: Re: lead computing optical sights
Message-ID: <1990Oct29.025649.6813@cbnews.att.com>
Date: 29 Oct 90 02:56:49 GMT
References: <1990Oct25.152148.2396@cbnews.att.com>
Sender: military@cbnews.att.com (William B. Thacker)
Organization: AT&T Bell Laboratories
Lines: 35
Approved: military@att.att.com



From: cga66@ihlpy.att.com (Patrick V Kauffold)
>From article <1990Oct25.152148.2396@cbnews.att.com>, by arthur@Eng.Sun.COM (Arthur Leung):
> 
> i was wondering about the development of the lead
> computing optical sight used in air gunnery.  when
> were these sights developed?
> 
> were these sights lead computing?  if so, what
> drove the optics?

Here is what I remember about the Mk52 director used for 5" mounts:

This system had a radar for range only - an operator matched a cursor
to the blip on an A-scope to get range.  This was fed to the director
as an analog signal.

The director operator put an illuminated circular reticle on the target,
and tracked the target manually.  The "computer" had gyroscopes to measure
angular motion in elevation and azimuth.  The lead angle was computed
by high-precision mechanical integrators (like planimeters) which
deflected the mirrors which projected the reticle.  The sight worked
like a primitive version of the HUD, but all electro-mechanical.
There was no magnification in the optics.

When the director operator had the target in the reticle, tracking
smoothly, he squeezed the key, and the 5" mount fired as fast
as the gun crew could load - about 1 round every 10-15 sec.

I only tried this once.  Couldn't hit shit, but great fun.

This was technology developed to defeat Japaneze Kamikaze attacks.
Similar sights were applied to the 40 mm and 20 mm mounts.  Totally
inadequate against jets.