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Date: Wed, 14 Feb 2007 15:32:57 -0500
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From: "Jeremy Fisher" <jffisher@gmail.com>
Subject: Re: [LML] Night vision goggles
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Steve,

I did the initial test flights in a fighter at low level using NVGs back in
1980, and have been involved off and on in their development since then.
They are certainly amazing devices which can greatly ease pilot workload at
night.  However there are snags, as ever.

There are essentially 2 types readily available, Gen 2 and Gen 3.  Gen 2
work down to about 1/4 moonlight and have fairly wide frequency response.
They are useless looking through any kind of glass, but plexiglas or other
plastics have a much lower impact on performance.  The cheaper ones are
generally Gen 2, which are OK if you understand their limitations. Gen 3 are
higher performance down to starlight, and work in the green part of the
spectrum.

The main concerns are cockpit lighting, head mounting and training.  You
absolutely cannot use NVGs with red or white lighting, they are totally
dazzled by even dim light  reflections.  What we did was fit the front lens
of the NVGs with a red filter, then modify the cockpit lights to a specific
narrow band green standard; we used EL strips, but you have to play with
different lights and filters.  Theater floodlight filter material is cheap
and works well.  Turning the cockpit lights out does not work, because the
NVGs are focussed at infinity, and you cannot read the instruments through
them.

Head mounting could be a problem, unless you wear a helmet.  You can hold
them, but it would be difficult in a high stress situation, especially in
turbulence.  They often come with some form of head mount, and you would
have to work out how to adapt it for our purposes.

Finally they lack a degree of depth perception, and are of course
monochromatic. Make sure that they lack magnification as well. for obvious
reasons; there are a few that are not 1:1.   You would need to practice
using them in a safe environment beforehand, with a safety pilot on board.
Having said all that, I would definitely want to have a set around if I had
to do a forced landing at night.  They would turn an impossible situation
into a merely difficult one.

Jerry

On 2/14/07, S. Reeves <sreeves@sc.rr.com> wrote:
>
> What do you guys think about night vision goggles for added safety
> factor for single engine night flying.  I'm talking about for the
> unfortunate event of engine failure, not tooling around wearing them
> ;).  The prices on them have been reduced over the years, and it
> would be cheaper than buying a twin.  Any thoughts?
>
> Steve Reeves
> Glasair 1FT 38SR
>
>
> --
> For archives and unsub http://mail.lancaironline.net/lists/lml/
>

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<div>Steve,</div>
<div>&nbsp;</div>
<div>I did the initial test flights in a fighter at low level using NVGs back in 1980, and have been involved off and on in their development since then.&nbsp; They are certainly amazing devices which can greatly ease pilot workload at night.&nbsp; However there are snags, as ever.
</div>
<div>&nbsp;</div>
<div>There are essentially 2 types readily available, Gen 2 and Gen 3.&nbsp; Gen 2 work down to about 1/4 moonlight and have fairly wide frequency response.&nbsp; They are useless looking through any kind of glass, but plexiglas or other plastics have a much lower impact on performance.&nbsp; The cheaper ones are generally Gen 2, which are OK if you understand their limitations.&nbsp;Gen 3 are higher performance down to starlight, and work in the green part of the spectrum.
</div>
<div>&nbsp;</div>
<div>The main concerns are cockpit lighting, head mounting and training.&nbsp; You absolutely cannot use NVGs with red or white lighting, they are totally dazzled by even dim light&nbsp; reflections.&nbsp; What we did was fit the front lens of the NVGs with a red filter, then modify the cockpit lights to a specific narrow band green standard; we used EL strips, but you have to play with different lights and filters.&nbsp; Theater floodlight filter material is cheap and works well.&nbsp; Turning the cockpit lights out does not work, because the NVGs are focussed at infinity, and you cannot read the instruments through them.
</div>
<div>&nbsp;</div>
<div>Head mounting could be a problem, unless you wear a helmet.&nbsp; You can hold them, but it would be difficult in a high stress situation, especially in turbulence.&nbsp; They often come with some form of head mount, and you would have to work out how to adapt it for our purposes.
</div>
<div>&nbsp;</div>
<div>Finally they lack a degree of depth perception, and are of course monochromatic.&nbsp;Make sure that they lack magnification as well. for obvious reasons;&nbsp;there are a few that are not 1:1.&nbsp; &nbsp;You would need to practice using them in a safe environment beforehand, with a safety pilot on board.&nbsp; Having said all that, I would definitely want to have a set around if I had to do a forced landing at night.&nbsp; They would turn an impossible situation into a merely difficult one.
</div>
<div>&nbsp;</div>
<div>Jerry<br>&nbsp;</div>
<div><span class="gmail_quote">On 2/14/07, <b class="gmail_sendername">S. Reeves</b> &lt;<a href="mailto:sreeves@sc.rr.com">sreeves@sc.rr.com</a>&gt; wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">What do you guys think about night vision goggles for added safety<br>factor for single engine night flying.&nbsp;&nbsp;I&#39;m talking about for the
<br>unfortunate event of engine failure, not tooling around wearing them<br>;).&nbsp;&nbsp;The prices on them have been reduced over the years, and it<br>would be cheaper than buying a twin.&nbsp;&nbsp;Any thoughts?<br><br>Steve Reeves<br>Glasair 1FT 38SR
<br><br><br>--<br>For archives and unsub <a href="http://mail.lancaironline.net/lists/lml/">http://mail.lancaironline.net/lists/lml/</a><br></blockquote></div><br>

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