Today's Message Index:
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1. 10:35 AM - Re: Re: Has anyone used very high temp silicone FWF? (Ernest Christley)
2. 06:23 PM - Re: Re: Has anyone used very high temp silicone FWF? (Robert L. Nuckolls, III)
3. 09:09 PM - Re: Re: Stratux RS-232 Wx+Trfc Out to various navigators... (TImothy Shankland)
Message 1
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| Subject: | Re: Has anyone used very high temp silicone |
FWF?
On Saturday, December 19, 2020, 7:05:03 PM EST, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
=C2-=C2- A mock firewall sheet is fitted with the proposed feed
=C2-=C2- thru system. A propane fired burner is positioned a
=C2-=C2- few feet off the front side of the firewall. Athermocouple
=C2-=C2- is positioned about 6" off the firewall right infront
=C2-=C2- of the test article.
=C2-=C2- The test setup is bathed in propane powered flame
=C2-=C2- sufficient to push the thermocouple reading to 2000
=C2-=C2- plus or minus a hundred or so degrees . . . for
=C2-=C2- ten minutes.
With all due respect, why doesn't the test require that the test article al
so support the weight of firewall forward components while the test is bein
g conducted?=C2- For a firewall that is held together and to the airplane
with either rivets that melt at around 950F (but are mechanically useless
above 500F), and epoxy that will melt above 300F (at best), all that test s
hows is that your wire bundle will be safe as the pieces of your airplane c
rash to the ground in different spots.=C2- Maybe the hope is that the cau
lk can hold the airplane together.
I understand safety margins, and a desire to get the best protection availa
ble.=C2- But as with everything else, there comes a point when the search
for safety crosses over to being useless, then comical, or may even reach
counter productive. I wonder if Mr. Thurman has run the test on a firewall
connected to fuselage and engine to see how long they stay together.=C2-
The front half of a fuselage that is already heading to the recycle plant w
ould be all that's necessary.
Message 2
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| Subject: | Re: Has anyone used very high temp silicone |
FWF?
On Saturday, December 19, 2020, 7:05:03 PM EST, Robert L. Nuckolls,
III <nuckolls.bob@aeroelectric.com> wrote:
A mock firewall sheet is fitted with the proposed feed
thru system. A propane fired burner is positioned a
few feet off the front side of the firewall. A thermocouple
is positioned about 6" off the firewall right in front
of the test article.
The test setup is bathed in propane powered flame
sufficient to push the thermocouple reading to 2000
plus or minus a hundred or so degrees . . . for
ten minutes.
With all due respect, why doesn't the test
require that the test article also support
the weight of firewall forward components
while the test is being conducted?
Not for individual, non-structural components.
To be sure, there are very few such devices
intended to maintain firewall integrity
while taking wire bundles from one side to
the other. The pass-thrus I illustrated
are one such device, bulkhead electrical
connectors are another. They may have tested
things like cabin heat mixer boxes on
that fixture.
Chapter 13 of this document
https://tinyurl.com/yd4kapvh
speaks to those components. The handbook
is 235 pages and covers a constellation
of materials and applications.
For a firewall that is held together and to the airplane with either
rivets that melt at around 950F (but are mechanically useless above 500F),
. . . this isn't a test of the firewall
but only a component bolted to the firewall.
and epoxy that will melt above 300F (at best), all that test shows is
that your wire bundle will be safe as the pieces of your airplane
crash to the ground in different spots. Maybe the hope is that the
caulk can hold the airplane together.
Composite aircraft are another study/
solution and may also be covered in
the cited document.
I understand safety margins, and a desire to get the best protection
available. But as with everything else, there comes a point when the
search for safety crosses over to being useless, then comical, or may
even reach counter productive. I wonder if Mr. Thurman has run the
test on a firewall connected to fuselage and engine to see how long
they stay together. The front half of a fuselage that is already
heading to the recycle plant would be all that's necessary.
Dunno . . . I didn't work in that
facility routinely. I only conducted
tests germane to my tasks. Those were not
'searches for safety' rather qualification
tests of specific components conducted
in compliance with standards of the day.
To be sure, firewall forward fires are
rare and are fueled by either gasoline
(for which you have shutoffs), engine
oil which has escaped from compromised
plumbing . . . or gross disassembly
of the engine (thrown jug or a rod
punching a hole in the crankcase).
The later case is probably the impetus
for testing at the really high energy
levels for so long an interval of time.
6-8 qts of 50W represents a huge chunk
of energy.
I've often wondered about aluminum cowls
burning thru and exposing the windscreen
to direct flame.
But keep in mind too that this thread
was about tubes of fire stop goop and
goos from the BigBox stores. And to
be sure, about any of those would
probably be adequate to the task. Given
that they are shielded by the fire-sleeve.
The point I would emphasize is that stuff squirted
from a tube is 'messy' from the get
go. Raytheon-Beech was pretty hard
over for finding/developing assembly-
line and field-mechanic friendly while
meeting requirements cited in the FARS.
This discussion is more about refinement
of process than optimization of performance.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 3
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| Subject: | Re: Stratux RS-232 Wx+Trfc Out to various navigators... |
I found that commercially available cables with micro USB had too large a
voltage drop for my system to work. I bought a micro USB plug that I could
solder heavier wires.
On Thursday, December 17, 2020, 10:07:01 PM MST, andymeyer <meyerkc135
@gmail.com> wrote:
>
The CP2102 only provides the serial output.
I used the Boost Buck converter, a separate module that I installed in the
Box, to power the Raspberry Pi. I wired it directly to the Raspberry Pi, no
t through the micro USB port. Mine is installed in the airplane. Wired to a
breaker and to the IFD.
I would anticipate that the MicroUSB may provide enough power assuming your
runs are short and your supply is running at the upper end of the pi volta
ge range. I prefer a more permanent connection than the micro USB. If you'r
e using a USB GPS, you'll need to make sure that you can squeeze all four U
SB devices in the 4 USB ports, or work an alternate option. You can try sho
rt USB extension cables as well. They make them with 90-degree connectors w
hich may help.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=499711#499711
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=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
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