Today's Message Index:
----------------------
1. 08:51 AM - Re: Starter Contactor location on a Long-EZ (Robert L. Nuckolls, III)
2. 10:25 AM - Re: Starter Contactor location on a Long-EZ (Airdog77)
3. 03:48 PM - Re: Re: Starter Contactor location on a Long-EZ (Robert L. Nuckolls, III)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Starter Contactor location on a Long-EZ |
At 03:26 PM 1/28/2018, you wrote:
>My own cost/benefit analysis led me to buck the aeroelectric
>conventional wisdom and do it different.
Keep in mind that we're talking several issues
only slightly intertwined . . .
One is selection of parts and ARCHITECTURE.
I'd be surprised if more than a couple percent
of OBAM aircraft flying were heavily influenced
by the AeroElectric Connection. Yet, they are
all flying and perform to builder's expectations
else they would get FIXED. That's one of the big
reasons for going the OBAM aviation route . . . if
you don't like it, fix it.
The second issue is failure mode effects . . .
irrespective of the architecture floats your boat
. . . or flies your airplane . . . the project
benefits greatly from FAILURE TOLERANT design.
I.e. loss of no single PROPERLY INSTALLED COMPONENT
should put the outcome of the flight at risk.
The last, and perhaps the most important focuses on
that word "PROPERLY" . . . we've read waaayyy too many
stories about bad days in the cockpit wherein the
installation and sometimes the selection of components
fabricated an ACCIDENT WAITING TO HAPPEN.
All the worrying in the world about architecture
and even parts selection produces no benefit unless
the two most important of those issues are skillfully
resolved. FAILURE TOLERANCE and PROPER INSTALLATION.
Some really 'nice' airplanes have gone down, some
with loss of life, for IGNORANT reasons implemented
by individuals who were not stupid . . . just inadequately
prepared to the task. Those root causes are invariably
unrelated to anything discussed outside of Chapter 17
in the 'Connection.
The place to start your educational endeavors is
in study of the history of the art. A study of
how-they-did-it in a C172 or PA28 may not be very
exciting, but there is confidence to be gained
in knowledge of successfully repeated experiments.
An advantage we have in OBAM aviation is the freedom
to explore new ideas. But the slickest new idea is
of little value if its failure modes or lack of
attention to process raises risk to unacceptable
levels.
Be wary of decisions driven by unsubstantiated
worries. We don't KNOW root cause in the
loss of Brian's airplane. If the loss personal to
Brian wasn't enough, loss to the community for not
knowing root cause was far worse. Worries that
prompt deviation from perhaps a century of successfully
repeated experiments do not add value to the
art and science of building low risk aircraft.
Further, they dilute the value of our $time$ expended
on seeking solutions for problems that can
only be imagined because we have no data.
Bob . . .
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Starter Contactor location on a Long-EZ |
Bob,
Thanks for your analysis of this incident. I always learn a ton through you and
others on this forum!
Just for clarification, our firewalls are 1/4" Finnish birch plywood with a ply
or two each side of fiberglass. Then the hot side gets a layer of fiberfrax covered
with a thin layer (0.016-0.025") of either stainless steel or aluminum.
As with researching any subject, there are invariably other characteristics that
appear and reveal themselves and add to the original topic being researched.
I am strongly leaning towards placing the starter contactor on the cold side
of the firewall, but not in response to Brian's incident, but more so as a matter
of logistical ease for my configuration that became clear to me the more I
researched this issue. To be certain, by doing this I'm not stating an overriding
concern for getting a high current cable through the firewall, it is again
merely one of logistics and space.
I will say --and not that this is my reasoning for a go/no-go decision-- that I've
learned over these past few days that placing the starter contactor on the
cold side of the firewall is a VERY common practice in the canard community --again,
for whatever reasons individual builders' have. Actually, surprisingly
common in fact.
Perhaps some of that has to do with the inherent design of canards, wiring and
space logistics (my overarching reason for going this route), tribal culture,
or just individual preference.
As you have alluded to many times, this flexibility is one of the outstanding characteristics
of the OBAM world... to adjust when necessary to optimize one's
build.
Regards,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477679#477679
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Starter Contactor location on a Long-EZ |
>
>
>I will say --and not that this is my reasoning for a go/no-go
>decision-- that I've learned over these past few days that placing
>the starter contactor on the cold side of the firewall is a VERY
>common practice in the canard community --again, for whatever
>reasons individual builders' have. Actually, surprisingly common in fact.
>
>Perhaps some of that has to do with the inherent design of canards,
>wiring and space logistics (my overarching reason for going this
>route), tribal culture, or just individual preference.
>
>As you have alluded to many times, this flexibility is one of the
>outstanding characteristics of the OBAM world... to adjust when
>necessary to optimize one's build.
. . . a well reasoned decision. My only concern about
this thread (and similar threads in the past) was
that some readers perceive value in moving their
contactor as a prophylactic against having
their airplane catch fire.
My sense is that you've got a handle on the
need/value/processes for risk management. A quality
that has very little to do with architecture.
May The Force be with you sir . . .
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|