Today's Message Index:
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1. 09:19 AM - Re: Video editing software (Hison Hison)
2. 05:01 PM - test (Robert L. Nuckolls, III)
3. 05:02 PM - Re: faston failures et. als. (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Video editing software |
What is the best way to edit a video now?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=502839#502839
Message 2
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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: faston failures et. als. |
At 10:02 AM 7/27/2021, you wrote:
>The issue of female "fast on" connectors losing their grip and
>creating a high resistance point is generally related to the quality
>of the connectors used. The connectors sold at the local auto parts
>stores are of inferior quality and often cause this sort of issue.
>Best to use the PIDG connectors that Bob N. recommends.
We've had several incidents of strobe switch failures
over the years. Had a builder report serial
failures on his airplane that took some time and
head scratching to figure out. This was probably
20 years ago.
http://aeroelectric.com/Pictures/Switches/Carling_Cutaway.jpg
http://aeroelectric.com/Pictures/Switches/Toggle_Switch_with_Fast-On_Tabs.jpg
If you study the images above you can plot the
pathway for current flow through the switch. Note
that there are 10 'ohmic' joints in (metal-to-metal)
the wire-to-wire pathway. There are 11 conductive
components that carry current to, through and
away from the switch.
Two of those joints are moving . . . saddle pivot
and contact interface. All the rest are non-moving
wherein various fabrication processes strive for
gas-tight, low resistance joining.
Loss of function for this assembly can have beginnings
at any one or combination of failures in the ohmic
joints. Degradation of a joint manifests in an
increase of resistance between the two components.
Increased resistance is followed by HEATING . . . just
a few degrees at first . . . but it's regenerative.
Heating exacerbates loss of conduction causing
increased heating which accelerates lost of conduction.
It's never a rapid process . . . it may take many
hours of operation to bring the whole thing down
to failure. Impending failures are often caught
visually . . . note the discoloration of the terminal
insulator here:
http://aeroelectric.com/Pictures/Switches/VL_Switch_Failure_2.jpg
This image suggests loss of integrity in the terminal-
to-wire crimp. Overt failure may still be months
off after hours of operation.
Modern flash tube strobe systems are particularly
prone to failures of this kind. Several compounding
reasons. (1) strobes are often operated for duration
of flight from engine start up to shut down. (2) The
flash tube strobe system is probably the most demanding
on the panel switch due to current draw . . . a draw
that is HIGHEST at low bus voltages when the modern,
constant power high voltage circuits INCREASE drain
to maintain performance.
We've studied several switch failure cases here on
the List over the years. EVERY failure began with localized
heating as a consequence of degraded conduction in ONE
joint. It was not uncommon for heating to degrade surrounding
materials to the point where multiple joints began to
participate in total failure of the switch.
Failure science is an interesting study in material
characteristics and physics. Without a well considered
study of evidence, it's easy to blame the quality of
a component but one needs to be mindful of the
general nature of failures. They generally have
a single point of origin that can cascade into
multiple events ending in total failure.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
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