The voltage generated by rotor wash is significant. Every grab a spark plug
wire (by accident)? Triple that experience.
Remember 7th grade shop, "It's the amps that kill you"
I was in a National Guard Field artillery unit and we would do air-assault
stuff. We needed a braided 10-guage size wire with a shepherds type hook on
the end. The other end of the cable was attached to a ground stake about 3'
long. You made damn sure that it was around the lifting hook on the helo
before the sling was attached. The fun job was the guy on top of the
howitzer who had to connect the sling while the CH-47 floated about 2 feet
over your head. We preferred the old CH-54's . At least they could lower a
cable.
Charlie
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ahne Oosterhof
Sent: Wednesday, July 18, 2007 6:14 PM
To: [log in to unmask]
Subject: Re: [TN] NTC - I wonder how much this job pays?
Let's see, I believe a cubic cm in free space is 1pF. That makes a cubic
meter 1uf. This helicopter probably represents at least 50 cubic meters, or
is equivalent to 50uF. Charge that up to 150kV: I=CV/t= 50E-6*150E3/1sec
(guess) = 7.5 A. No, too much for my body.
But highly amusing!
Rotor wash blowing off charge: maybe, when it is foggy, but otherwise I
would not count on it.
All this reminds me off my college years, when I worked a short period for
the railroad and had to measure the thickness (wear) of the overhead wires:
at 1500Vdc, standing on a wooden ladder on the rails, you could feel a
tickle, and in foggy weather more than a tickle. In the rain we did not do
this. (no wand big enough :) )
Ahne.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Upton, Shawn
Sent: Wednesday, 18 July, 2007 13:15
To: [log in to unmask]
Subject: Re: [TN] NTC - I wonder how much this job pays?
I suspect it doesn't last long, the charge that is. I think the rotor wash
is blowing off charge, as I doubt that the chopper presents that much
capacitance to ground, so as to sustain that arc. Even if it did, as soon
as the skid hits the ground, it'd dissapate the stored charge pretty quickly
I'd think.
Shawn Upton, KB1CKT
Test Engineer
Allegro MicroSystems, Inc
[log in to unmask]
603.626.2429/fax: 603.641.5336
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: Wednesday, July 18, 2007 2:52 PM
To: [log in to unmask]
Subject: Re: [TN] NTC - I wonder how much this job pays?
Air isn't a perfect dielectric. Wonder if any is left when it lands.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Wednesday, July 18, 2007 2:31 PM
To: [log in to unmask]
Subject: Re: [TN] NTC - I wonder how much this job pays?
I think it gives the arc that forms a place to go other than human flesh
while the helicoptor and the man come up to the same voltage as the line is
carrying...
Steve
________________________________
From: Bill Kasprzak [mailto:[log in to unmask]]
Sent: Wednesday, July 18, 2007 12:42 PM
To: TechNet E-Mail Forum; Steve Gregory
Subject: Re: [TN] NTC - I wonder how much this job pays?
Anybody know what the wand is for?
Reminds me of Harry Potter.
Steve Gregory <[log in to unmask]> Sent by: TechNet
<[log in to unmask]>
07/18/2007 11:07 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to Steve Gregory
<[log in to unmask]>
To
[log in to unmask]
cc
Subject
[TN] NTC - I wonder how much this job pays?
I know it's not Friday yet, but it seems pretty quiet out there. I just back
from vacation on Monday and haven't posted much...that's why I've been so
quiet.
I got a video clip yesterday that was pretty interesting. It's of a
"high-power" sort of job that makes one wonder how much these guys get paid
for doing it.
http://www.stevezeva.homestead.com/files/high_power_worker.wmv
I don't think anyone could pay me enough to perform that job...
Steve Gregory
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