Today's Message Index:
----------------------
1. 11:51 AM - Re: Fuses instead of breakers (Jeff Page)
2. 12:43 PM - Re: Re: Fuses instead of breakers (Robert L. Nuckolls, III)
3. 03:37 PM - Re: Re: Fuses instead of breakers (James Robinson)
4. 04:56 PM - Re: Re: Fuses instead of breakers (ROGER & JEAN CURTIS)
5. 04:56 PM - Re: Re: Fuses instead of breakers - too complicated (Jeff Luckey)
6. 06:47 PM - Re: Re: Fuses instead of breakers (James Robinson)
Message 1
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Subject: | Re: Fuses instead of breakers |
> >......Are there any other reasons why a pullable circuit breaker
> would be >preferred for this situation ?
> There are two seperate potential issues here. First, is there an
> alternate source
> of hydraulic pressure? If you have a practical hand pump available, then
> the nuisance trip issue is just that. If the electric pump is your
> only practical
> source of hydraulic power, then things are a little different. I
> could envision
> a scenario where the motor for the hydraulic pump has degraded such that
> the current draw trips the circuit protection, leaving you with a
> gear up landing,
> or potentially worse, a partial gear landing. Personally, I would prefer
> resettable circuit protection in that scenario.
There is a manual hand pump, so no emergency is created.
> "I have had to do one inflight reset on the Plasma III on one system
> once. The reset was successful and power was restored to the unit. I
> removed the unit and sent it back to Klaus for inspection. The fault
> was determined to be an overheat situation. That unit was located in
> an area without any real ventilation and without an form of cooling
> while operation in Arizona during the summer. the compartment temp
> was estimated to have exceeded 200 deg. F. The unit was modified to
> the latest version (lower heat output components and a ventilation
> port. The aircraft was modified to provide air circulation in that
> compartment. After 300+ hours on that unit no faults noted. The
> point, when the unit faulted it tripped the CB and was then reset
> and provided service throughout the remainder of that flight. "
Hmmm. If it immediately resumed functioning after resetting the
breaker, perhaps
the ignition never failed, but the heat (and probably higher currents
operating at
high temperatures) caused the breaker to nuisance trip.
> I will be interested in the results of your discussions with Klaus
> about powering the Lightspeed ignition. I know two people who are
> about to install these.
> There are no doubt many hundreds if not
> thousands of these flying. To the best of my
> knowledge, they are not "special" devices
< deserving of extra-ordinary attention.
They just get extra attention since pilots are more concerned with their
ignition failing than say their nav lights going out ;-)
> The relays are Bosch 12V/20A 0 332 209 137
> Those relays are not specifically
> crafted for motor control service. Having
> a crew-operated means by which a runaway
> can be controlled seems prudent.
A pullable breaker would stop current flow caused by a stuck relay,
and the manual pump could be used to operate the gear, so there is
no significant flight risk.
Those relays do look undersized to me.
Better relays might reduce long term maintenance however. Or perhaps
just carry a spare along might be the most practical approach. I think
the latter ?
Jeff Page
Dream Aircraft Tundra #10
Message 2
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Subject: | Re: Fuses instead of breakers |
There is a manual hand pump, so no emergency is created.
Then a robust fuse solution goes toward a cleaner
panel and possibly a cleaner plan B. When THIS
happens, do THAT . . . every time.
>"I have had to do one inflight reset on the Plasma III on one system
>once. The reset was successful and power was restored to the unit. I
>removed the unit and sent it back to Klaus for inspection.
> . . .<snip>
>The point, when the unit faulted it tripped the CB and was then reset
>and provided service throughout the remainder of that flight."
Hmmm. If it immediately resumed functioning after resetting the
breaker, perhaps the ignition never failed, but the heat (and probably
higher currents operating at high temperatures) caused the breaker
to nuisance trip.
The keyword here is "nuisance". I've had to cut the
TC guys some slack for being somewhat submissive to
nuisance trips . . . to strive for the elegant solution
can sometimes be very time consuming and expensive.
One is well advised to trade off cost/benefit ratios.
In the OBAM aircraft world, we're not only able, we are
encouraged to refine any system's configuration in way
that increases the displacement between it's experimental
roots and an enduring recipe for success.
But when one gets a 'nuisance trip' with current protection
that is nearly 2.5 times the published draw numbers . . .
there are reasons to seek answers to some serious questions.
There is a clash of postulates which beg resolution.
They just get extra attention since pilots are more concerned with their
ignition failing than say their nav lights going out ;-)
ABSOLUTELY! Which is why I've recommended that electrically
dependent engine accessories drive from always hot battery
bus with totally independent power paths. If two ignition
systems require power and two batteries are available, then
split the systems between the batteries.
But when a 2A device trips a 5A breaker . . . well . . .
A pullable breaker would stop current flow caused by a stuck relay,
and the manual pump could be used to operate the gear, so there is
no significant flight risk.
Great.
Those relays do look undersized to me.
Better relays might reduce long term maintenance however. Or perhaps
just carry a spare along might be the most practical approach. I think
the latter ?
I thought we were talking about a much larger
hydraulic system. The amount of snort needed to
operate the gear in floats is much smaller than
that used on a GlasAir or Lancair. I think these
relays will be fine and since you have a backup
hand pump, your risks are quite low.
Bob . . .
Message 3
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Subject: | Re: Fuses instead of breakers |
Hi Bob=0AI built a cold air induction for my glasair and will have an alter
nate filtered air when on the ground.- I take off with 10 deg of flaps.
- Could there be a way to sequence this alternate air door with the flaps
?- When the flaps come up the the door opens to allow ram air and when th
e flaps come down it closes the ram air.- Am I getting to complicated?=0A
Jim=0A=0A-=0AJames Robinson=0AGlasair lll N79R=0ASpanish Fork UT U77=0A
=0A=0A________________________________=0A From: "Robert L. Nuckolls, III" <
nuckolls.bob@aeroelectric.com>=0ATo: aeroelectric-list@matronics.com =0ASen
t: Friday, January 27, 2012 1:40 PM=0ASubject: Re: AeroElectric-List: Re: F
bert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>=0A=0AThere is a manu
al hand pump, so no emergency is created.=0A=0A- - Then a robust fuse s
olution goes toward a cleaner=0A- - panel and possibly a cleaner plan B
. When THIS=0A- - happens, do THAT . . . every time.=0A=0A>"I have had
to do one inflight reset on the Plasma III on one system=0A>once. The reset
was successful and power was restored to the unit. I=0A>removed the unit a
nd sent it back to Klaus for inspection.=0A> . . .<snip>=0A>The- point, w
hen the unit faulted it tripped the CB and was then reset=0A>and provided s
ervice throughout the remainder of that flight."=0A=0AHmmm.- If it immedi
ately resumed functioning after resetting the=0Abreaker, perhaps the igniti
on never failed, but the heat (and probably=0Ahigher currents operating at
high temperatures) caused the breaker=0Ato nuisance trip.=0A=0A- - The
keyword here is "nuisance". I've had to cut the=0A- - TC guys some slac
k for being somewhat submissive to=0A- - nuisance trips . . . to strive
for the elegant solution=0A- - can sometimes be very time consuming an
d expensive.=0A- - One is well advised to trade off cost/benefit ratios
.=0A=0A- - In the OBAM aircraft world, we're not only able, we are=0A
- - encouraged to refine any system's configuration in way=0A- - th
at increases the displacement between it's experimental=0A- - roots and
an enduring recipe for success.=0A=0A- - But when one gets a 'nuisance
trip' with current protection=0A- - that is nearly 2.5 times the publi
shed draw numbers . . .=0A- - there are reasons to seek answers to some
serious questions.=0A- - There is a clash of postulates which beg reso
lution.=0A=0AThey just get extra attention since pilots are more concerned
with their=0Aignition failing than say their nav lights going out ;-)=0A=0A
- - ABSOLUTELY! Which is why I've recommended that electrically=0A-
- dependent engine accessories drive from always hot battery=0A- - bu
s with totally independent power paths. If two ignition=0A- - systems r
equire power and two batteries are available, then=0A- - split the syst
ems between the batteries.=0A=0A- - But when a 2A device trips a 5A bre
aker . . . well . . .=0A=0AA pullable breaker would stop current flow cause
d by a stuck relay,=0Aand the manual pump could be used to operate the gear
, so there is=0Ano significant flight risk.=0A=0A- - Great.=0A=0AThose
relays do look undersized to me.=0A=0ABetter relays might reduce long term
maintenance however.- Or perhaps=0Ajust carry a spare along might be the
most practical approach.- I think=0Athe latter ?=0A=0A- - I thought w
e were talking about a much larger=0A- - hydraulic system. The amount o
f snort needed to=0A- - operate the gear in floats is much smaller than
=0A- - that used on a GlasAir or Lancair. I think these=0A- - relay
s will be fine and since you have a backup=0A- - hand pump, your risks
- - - - - - - - - - - - - - -Matt Dralle, List
======
Message 4
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Subject: | Re: Fuses instead of breakers |
Hi Bob
I built a cold air induction for my glasair and will have an
alternate filtered air when on the ground. I take off with 10 deg of
flaps.
Could there be a way to sequence this alternate air door with the flaps?
When the flaps come up the the door opens to allow ram air and when the
flaps come down it closes the ram air. Am I getting to complicated?
Jim
Is your alternate air door electrically
operated? If so, you can use a switch, activated by the flaps, to open
the
door when flaps are up, and close as soon as flaps are cycled down.
Roger
Message 5
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Subject: | Re: Fuses instead of breakers - too complicated |
James,
The short answer is: yes, you are getting too complicated.
When you try to do something like that, you must view the situation from
every conceivable angle to determine if there is some scenario, however
weird or un-likely, that those automatic actions can actually get you into
trouble.
Airliners have many systems that interact so that when you do A, B & C
happen automatically - however - Airline pilots receive a LOT of systems
training and recurrent training.
Having issued that caveat, I have to say (just like I tell my clients - I'm
and IT consultant) "we can do (absolutely) anything you want, it just takes
time and money".
-Jeff Luckey
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of James
Robinson
Sent: Friday, January 27, 2012 15:34
Subject: Re: AeroElectric-List: Re: Fuses instead of breakers
Hi Bob
I built a cold air induction for my glasair and will have an alternate
filtered air when on the ground. I take off with 10 deg of flaps. Could
there be a way to sequence this alternate air door with the flaps? When the
flaps come up the the door opens to allow ram air and when the flaps come
down it closes the ram air. Am I getting to complicated?
Jim
James Robinson Glasair lll N79R Spanish Fork UT U77
_____
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Sent: Friday, January 27, 2012 1:40 PM
Subject: Re: AeroElectric-List: Re: Fuses instead of breakers
<nuckolls.bob@aeroelectric.com>
There is a manual hand pump, so no emergency is created.
Then a robust fuse solution goes toward a cleaner
panel and possibly a cleaner plan B. When THIS
happens, do THAT . . . every time.
>"I have had to do one inflight reset on the Plasma III on one system
>once. The reset was successful and power was restored to the unit. I
>removed the unit and sent it back to Klaus for inspection.
> . . .<snip>
>The point, when the unit faulted it tripped the CB and was then reset
>and provided service throughout the remainder of that flight."
Hmmm. If it immediately resumed functioning after resetting the
breaker, perhaps the ignition never failed, but the heat (and probably
higher currents operating at high temperatures) caused the breaker
to nuisance trip.
The keyword here is "nuisance". I've had to cut the
TC guys some slack for being somewhat submissive to
nuisance trips . . . to strive for the elegant solution
can sometimes be very time consuming and expensive.
One is well advised to trade off cost/benefit ratios.
In the OBAM aircraft world, we're not only able, we are
encouraged to refine any system's configuration in way
that increases the displacement between it's experimental
roots and an enduring recipe for success.
But when one gets a 'nuisance trip' with current protection
that is nearly 2.5 times the published draw numbers . . .
there are reasons to seek answers to some serious questions.
There is a clash of postulates which beg resolution.
They just get extra attention since pilots are more concerned with their
ignition failing than say their nav lights going out ;-)
ABSOLUTELY! Which is why I've recommended that electrically
dependent engine accessories drive from always hot battery
bus with totally independent power paths. If two ignition
systems require power and two batteries are available, then
split the systems between the batteries.
But when a 2A device trips a 5A breaker . . . well . . .
A pullable breaker would stop current flow caused by a stuck relay,
and the manual pump could be used to operate the gear, so there is
no significant flight risk.
Great.
Those relays do look undersized to me.
Better relays might reduce long term maintenance however. Or perhaps
just carry a spare along might be the most practical approach. I think
the latter ?
I thought we were talking about a much larger
hydraulic system. The amount of snort needed to
operate the gear in floats is much smaller than
that used on a GlasAir or Lancair. I think these
relays will be fine and since you have a backup
hand pump, your risks
<http://www.matronics.com/Navigator?AeroElectric-List>
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Message 6
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Subject: | Re: Fuses instead of breakers |
Thanks Roger=0AIt was going to be a simple cable operation, but I thought I
would explore other alternatives before making a final decision.=0AJim=0A
=0A-=0AJames Robinson=0AGlasair lll N79R=0ASpanish Fork UT U77=0A=0A=0A
________________________________=0A From: ROGER & JEAN CURTIS <mrspudandco
mpany@verizon.net>=0ATo: aeroelectric-list@matronics.com =0ASent: Friday, J
anuary 27, 2012 5:53 PM=0ASubject: RE: AeroElectric-List: Re: Fuses instead
of breakers=0A =0A=0A--- --- Hi Bob=0A--- --- I bu
ilt a cold air induction for my glasair and will have an=0Aalternate filter
ed air when on the ground.- I take off with 10 deg of flaps.=0ACould ther
e be a way to sequence this alternate air door with the flaps?=0AWhen the f
laps come up the the door opens to allow ram air and when the=0Aflaps come
down it closes the ram air.- Am I getting to complicated?=0A--- -
-- Jim=0A=0A--- --- --- --- Is your alternate a
ir door electrically=0Aoperated?- If so, you can use a switch, activated
by the flaps, to open the=0Adoor when flaps are up, and close as soon as fl
aps are cycled down.=0A=0A--- --- --- --- Roger
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