[simpits-tech] Gun Sight update
Craig Rochester
simpits-tech@simpits.org
Sat, 18 Jan 2003 14:24:18 -0500
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If you find an optic expert (maybe a forum), please let me know . I've been plugging away at studying the
subject and have lots of questions.
I found a reference to A-10's HUD design in: "Visual Instrumentation, Optical Design and Engineering
Principles, Pantazis Mouroulis- McGraw/Hill Handbooks"
My typing:
"...The HUD concept calls for the projection of data to the pilot's eyes from the face of a CRT that is
located in the vicinity of his (pilot's) knees.
Projected data may involve flight instrumentation information, such as speed, altitude...the data is displayed
on the CRT face; is collimated (projected to infinity) by a high-quality lens system; and then is reflected to
the pilot's eyes via a beam-splitting plate called a combining glass. This combining glass will have a
dichroic coating on one surface, designed specifically to reflect the wavelength (generally quite
monochromatic) of the CRT. This eliminates the need for correction of chromatic aberrations in the HUD lens
design.
Unique to the HUD optics is the fact that the exit pupil of the lens is located at the pilot's head, a
considerable distance from the projection lens itself. Also unique is the fact that, while the HUD lens will
generally be quite large, with a very fast f-number, the actual system pupil size is determined by the size,
spacing and location of the pilot's eyes..."
This link has some info too:
http://www.usaarl.army.mil/hmdbook/cp_003.htm
Craig R.
-----Original Message-----
From: simpits-tech-admin@simpits.org [mailto:simpits-tech-admin@simpits.org]On Behalf Of Keenan Akin
Sent: Saturday, January 18, 2003 10:56 AM
To: simpits-tech@simpits.org
Subject: Re: [simpits-tech] Gun Sight update
As far as the internal optical details, I'm not sure. I am a crew station designer but I am not an optics
expert.
K
Matt Bailey wrote:
How did it work in real life? -Matt BaileyOn Fri, 2003-01-17 at 20:49, Keenan Akin wrote:Just received my gun
sight reflector glass from Surplus Shed. Looks very nice. However, when I tried it out, I had the same
problem as with the plexiglas (double image). Initially disappointed, I experimented around with various
lenses and such and I think I may have stumbled upon something. When I hold the reflector about 20 inches
away from the reticle source and hold a fresnel lens (the cheap plastic type used for reading small type), the
double image seems to go away. Of course, the reticle image is way too big at this point. So, my next step
is to make a very small reticle. This should allow me to place the lens and the reflector in their
appropriate location and produce the correct size reticle reflection. Stay tuned for
developments.Keenan_______________________________________________Simpits-tech mailing
listSimpits-tech@simpits.orghttp://www.simpits.org/mailman/listinfo/simpits-techTo unsubscribe, please see the
instructions at the bottom of the above page. Thanks!.
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<BODY>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2>If you=20
find an optic expert (maybe a forum), please let me know . I've =
been=20
plugging away at studying the subject and have lots of=20
questions.</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2>I=20
found a reference to A-10's HUD design in: "<U>Visual Instrumentation, =
Optical=20
Design and Engineering Principles</U>, Pantazis Mouroulis- McGraw/Hill=20
Handbooks"</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2>My=20
typing:</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial><SPAN=20
class=3D171404218-18012003><FONT face=3DArial>"...</FONT></SPAN>The HUD =
concept=20
calls for the projection of data to the pilot's eyes from the face of a =
CRT that=20
is located in the vicinity of his (<EM>pilot's</EM>) =
knees.</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT =
face=3DArial></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial>Projected data =
may involve=20
flight instrumentation information, such as speed, altitude...the data =
is=20
displayed on the CRT face; is collimated (projected to infinity) by a=20
high-quality lens system; and then is reflected to the pilot's eyes via =
a=20
beam-splitting plate called a <EM>combining glass. </EM>This =
combining=20
glass will have a dichroic coating on one surface, designed specifically =
to=20
reflect the wavelength (generally quite monochromatic) of the CRT. =
This=20
eliminates the need for correction of chromatic aberrations in the HUD =
lens=20
design.</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT =
face=3DArial></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial>Unique to the =
HUD optics is=20
the fact that the exit pupil of the lens is located at the pilot's head, =
a=20
considerable distance from the projection lens itself. Also unique =
is the=20
fact that, while the HUD lens will generally be quite large, with a very =
fast=20
f-number, the actual system pupil size is determined by the size, =
spacing and=20
location of the pilot's eyes..."</FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT =
face=3DArial></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2>This=20
link has some info too: </FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial><A=20
href=3D"http://www.usaarl.army.mil/hmdbook/cp_003.htm">http://www.usaarl.=
army.mil/hmdbook/cp_003.htm</A></FONT></SPAN></DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D171404218-18012003><FONT face=3DArial color=3D#0000ff =
size=3D2>Craig=20
R.</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=3DOutlookMessageHeader><FONT face=3D"Times New Roman"=20
size=3D2>-----Original Message-----<BR><B>From:</B>=20
simpits-tech-admin@simpits.org =
[mailto:simpits-tech-admin@simpits.org]<B>On=20
Behalf Of</B> Keenan Akin<BR><B>Sent:</B> Saturday, January 18, 2003 =
10:56=20
AM<BR><B>To:</B> simpits-tech@simpits.org<BR><B>Subject:</B> Re:=20
[simpits-tech] Gun Sight update<BR><BR></FONT></DIV>As far as the =
internal=20
optical details, I'm not sure. I am a crew station designer but =
I am not=20
an optics expert.<BR><BR>K<BR><BR>Matt Bailey wrote:<BR>
<BLOCKQUOTE cite=3Dmid:1042865515.2393.19.camel@localhost.localdomain=20
type=3D"cite"><PRE wrap=3D"">How did it work in real life?<BR><BR> =
-Matt Bailey<BR><BR>On Fri, 2003-01-17 at 20:49, Keenan Akin =
wrote:<BR></PRE>
<BLOCKQUOTE type=3D"cite"><PRE wrap=3D"">Just received my gun sight =
reflector glass from Surplus Shed. Looks <BR>very nice. However, when =
I tried it out, I had the same problem as with <BR>the plexiglas (double =
image). Initially disappointed, I experimented <BR>around with various =
lenses and such and I think I may have stumbled upon <BR>something. =
When I hold the reflector about 20 inches away from the <BR>reticle =
source and hold a fresnel lens (the cheap plastic type used for =
<BR>reading small type), the double image seems to go away. Of course, =
the <BR>reticle image is way too big at this point. So, my next step is =
to make <BR>a very small reticle. This should allow me to place the =
lens and the <BR>reflector in their appropriate location and produce the =
correct size <BR>reticle reflection. Stay tuned for =
developments.<BR><BR>Keenan<BR></PRE></BLOCKQUOTE><PRE =
wrap=3D""><!----><BR>_______________________________________________<BR>S=
impits-tech mailing list<BR><A class=3Dmoz-txt-link-abbreviated =
href=3D"mailto:Simpits-tech@simpits.org">Simpits-tech@simpits.org</A><BR>=
<A class=3Dmoz-txt-link-freetext =
href=3D"http://www.simpits.org/mailman/listinfo/simpits-tech">http://www.=
simpits.org/mailman/listinfo/simpits-tech</A><BR>To unsubscribe, please =
see the instructions at the bottom of the above page. =
Thanks!<BR><BR>.<BR><BR></PRE></BLOCKQUOTE><BR></BLOCKQUOTE></BODY></HTML=
>
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