Wellllll,
there's a couple or three engineering problems that have to get a
little love before the gadget would work. The video signal coming
from the sensor is typically 200 nanoamps full white and 1% of that
is visible enough to be seen. There is approximately 1 inch
separating the target (sensor) lead from the intensifier gating lead.
Here's part of the fun: volts/second equals amps/farad. Now lets put
some real-world numbers in that: 1,500 volts (the amount that has to
be switched) in 3 nanoseconds equals X amps in 300 picofarads
(switching electrode). Hmmmm, that comes to 225 kilowatts. With the
duty factor, it's barely over 5 watts average but quite a stroke of
lightning! Right next to the target. Not too amazing that in addition
to D-V failing, both RCA and Amperex (sensor mfr. & gated
intensifier mfr.) failed. Amperex HAD designed a slick, totem-pole
avalanche switch for the gadget, not bullet-proof but nice and small.
I had designed one for a different project that only died when near
ground-zero of a atomic bomb, however it needed a wheelbarrow to
move. Also, the Amperex device had the coupler allowing the switch to
safely ride on the 2,000 volt to 25,000 volt intensifier acceleration
voltage.
As
an aside (as usual ;o), you might have noticed I used “contract
engineer” instead of “consulting engineer.” A contract engineer
comes into a company to design what needs designing, fix what needs
fixin', and, if he's unfortunate, pour oil on some wounds. A
consultant comes into a company to take the blame when nothing works.
You'll find a LOT of consultants “working” for the gummit. This I
learned from a very wise man, my uncle. Look up A. Ernest Fitzgerald
in Wikipedia.
Since
this device was intended to convert the UH-I helicopter into a
gunship (1972, Vietnam “war”), and the range was 4 miles with the
required long lens, a serious image stabilizing system was mandatory.
The UH-1 isn't a nice, smooth craft, rather it's a collection of
10,000 loose parts kinda flying in formation. Most of the time.
Hopefully. I don't much like helicopters.
It
has to climb to a minimum of 500 feet before it can auto-rotate and
crash. Not fun. Lower than 500 feet, you just crash and I hear that
isn't fun either. It's a helicopter. If something isn't broken, it
soon will be. I don't much like them. My helicopter pilot was a
screwball.
...back
to the image stabilizer, I got to work with an old Chinese
physicist/mathematician who was a delight. He knew exactly zero
English and my Chinese was a bit lacking! You've heard math is the
universal language? Yeah, if you use the same symbology. He could
use western terminology and we did rather delightfully work together.
The image intensifier deflection sensitivity was calculated out as
something like 4/3rds times the square root of delta V where V is the
accelerator voltage.
Most
of the “motion” we needed to stabilize against was the terrific
vibration the turbine and the rotor set up. The vibration became much
worse if one blade of the rotor flew off. That would make me sad.
Without
the stabilizer, the image was nothing but a blur. With it, crystal
clear! It could go from 2 KV to 25KV in the old rattle-trap of a
chopper as smooth as silk! (I was kinda proud of it)
This
missive is a little slap-dash, maybe I'll straiten it out later.
Once
we had the camera and LASER
working to our satisfaction, it was time for real world trials plus
data taking to fit the army's requirements. That meant several trips
in the 10 wheel instrumented lab truck with the gear over to Crystal
Springs Reservoir, probably the darkest place in the entire area. San
Francisco was cooperative enough to send some of their fog into the
valley allowing us to do some with/without gating recording. With
gating on, it was almost like having X-ray vision. The silly thing
worked. Charlie Moore, the young tech working with me, and myself
also got a little freebie for the night work. Dinner was on Dalmo
Victor, the Bay area had 4,500 real restaurants, and we weren't
limited. “More wine, wench!” Ah! ...to be young and foolish!
My
part of the job was complete except for the usual 47 pounds of gummit
& military paperwork plus MTBF (mean time before failure)
calculations which, under mil-spec, makes one cry. Boeing and the
Italian Navy had already ordered units for their hydrofoils. Seems
submerged, but still floating logs are a real problem for them at
night. The LASER (910
nanometer wavelength) illuminated camera made them stand out as if
they were lit up. They were, and no water reflection at the LASER's
910 nm.
A
couple of months later, I got a phone call from my engineering
manager at D-V, Justin Rouge, inviting me to come and see some video
footage back from Vietnam. I mention Justin because all of the
engineering staff really liked him. He sat out to become an engineer
but had to settle for administration since he wasn't too bright.
Everybody who can't make the grade in assembly, cafeteria, facility
maintenance, etc. sends their dregs to administration! (I can't help
it..)
One
morning, the young grandson, about 30, of the company's founder,
decided he needed his Jaguar XKE washed and filled with gas. He
called into engineering and asked specifically for me. Now poor
Justin knew I was paid regardless if da boss wants me and my rather
substantial pay came out of his budget. This being one of President
Peanut's gas crisis times, I'd probably be in line for hours. Justin
had a nervous reaction when things weren't going right; he blew
repeatedly through his mustache, earning him the nickname “Puff,
the Magic Dragon.” BTW, the Jag is a tractor. Zero to 60 in a week
give or take, understears like a sow with rickets, and has a British
gearbox (sez it all). It also leaks oil. Looks cool though.
Back
to the Vietnam video, there were 6 or 7 D-V employees plus a pair of
army brass in attendence. I knew the video would be messy, I was too
familiar with what combat did and the 100 round per second minigun is
just plain nasty.
The
range display was indicating 1,700 yards and the video window about a
hundred feet deep (no display, just approx.). The image was as clear
as if we were just a couple of hundred feet away on a sunny day, no
VC showing, just some women. The gunner cut loose.
Dresden,
Hiroshima, and Nagasaki doesn't justify cold-blooded murder even if
North Vietnamese women were considered deadly. Made me sick. What
really got me was the army brass cheering and high-fiving each other.
That's
the reason I told Grumman and Sandia National Labs I wouldn't work on
offensive weaponry.
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