Today's Message Index:
----------------------
1. 08:11 AM - Re: Contacter, or not? (Robert L. Nuckolls, III)
2. 08:18 AM - Re: D.A.R question about fuse access (Robert L. Nuckolls, III)
3. 08:20 AM - Re: glass fuses (Robert L. Nuckolls, III)
4. 08:56 AM - Solid State Relays (John Burnaby)
5. 09:15 AM - Re: glass fuses (Ernest Kells)
6. 09:41 AM - Re: Solid State Relays (John Burnaby)
7. 10:04 AM - Re: D.A.R question about fuse access ()
8. 10:20 AM - Re: Solid State Relays (Matt Prather)
9. 10:53 AM - Re: Solid State Relays (Richard Tasker)
10. 10:53 AM - Re: Re: Solid State Relays (Richard Tasker)
11. 11:53 AM - Re: D.A.R question about fuse access (Ernest Christley)
12. 08:51 PM - Re: glass fuses (Bob McCallum)
13. 09:15 PM - Situational awareness as an instrument of flight. (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Contacter, or not? |
At 06:50 PM 7/15/2009, you wrote:
>
>Bob,
>
>Your comments gave me another idea.. If you only have 12-14A to play with
>(little dynamo), and the airplane has a starter.. And your normal running
>power budget is a fairly high percentage of the output of the dynamo..
>One could install a battery contactor (or starter relay) just for running
>the starter - in series with any starter/engine mounted relay/solenoid.
>Once the engine is running, the current draw from the monster contactor
>can be eliminated and you can drop back to a more power-frugal relay for
>driving the rest of the electronics on the airplane - a relay installed in
>parallel. I can't think of any downside.
That would work too. I'm thinking that for small airplanes,
the manual battery switch makes the most sense. They're light
and inexpensive.
I've got a prototype contactor power manager on the bench but
didn't get to finish evaluating it before I had to pull
the plugs and start moving equipment and inventory.
It would allow the builder to achieve low power operation
with an el-cheeso contactor. Further, if the contactor
needs replacing, you don't have to replace the associated
electronics too . . . and vice versa
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 2
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| Subject: | Re: D.A.R question about fuse access |
At 05:25 PM 7/15/2009, you wrote:
>Good Evening Glenn,
>
>My primary instructor kept the airspeed covered up most of the time.
>I learned to control airspeed via the sound and by the feel of the controls.
>
>Who needs an airspeed indicator?<G>
Only those not skilled in doing without them. When I
checked out new renters in our 150's I used to demonstrate
that "sticking the upper edge of the cowl on the
horizon" got you an 80 mph climb. I further demonstrated
that if the horizon is visible over the nose, you cannot
be too slow. After that, paying attention to power settings
pretty much covers the bases for not having an unhappy day
in the pattern.
I found this necessary/useful when new renters were
transitioning to an uncontrolled field sharing a 5
mile radius with 5 other uncontrolled fields. It was
a good idea to keep your eyes on the surrounding
environment as opposed to sticking the needles on some
finely tuned value for speeds and power.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 3
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At 09:06 PM 7/15/2009, you wrote:
>That is really what you should be using (is ATO blade type fuses) over the
> >glass fuses. From our experience, using glass fuses has many negatives and
> >they aren't something we'd really recommend for airplanes anymore.
>
> Bob> Absolutely! These have fragile internal connections at
> the ends of the fusible links . . . they also used large
> area, low pressure connections in their holders. Not
> gas-tight.
>
>Hi all: 1st time posting to this list.
Welcome aboard sir!
>
>Years ago I owned a "75 Celica GT that had an electric fuel
>pump. The car kept quitting for no apparent reason (usually when my
>girlfriend drove it). Ended up my favorite auto mechanic found the
>fuse end cap was loose that fed the fuel pump. There is no way I
>would use glass fuses for anything in an aircraft.
Hmmm . . . that too. I've seen those critters get
'unhooked' inside on several occasions myself. Those
little two-legged plastic critters may look cheesy
but they're the culmination of a century of lessons
learned and recipes for success with very long
field histories.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 4
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| Subject: | Solid State Relays |
Saw these
http://www.futurlec.com/RelSS.shtml
and for $20 they look like possible replacements for the common
electro-mechanical relays that we now use. These are light, compact, and
very reliable. But I don't know if there are gradations of MOSFETs or if
they're just basic building blocks. The cost of these is about 1/8 of an
almost identical Teledyne unit and I wonder if "you get what you pay
for" is appropriate to apply here? Or is Teledyne just passing on the
costs of marketing, regulatory environment, lawyers, pensions, etc?
The only obvious downside that is evident from the data sheet is that
the load capability starts falling off at about 60 deg C, so
installation in an engine compartment is off the table without a blast
tube and heatsink.
One of these has a load spec of 240VAC @ 70A and another specs 100VDC @
40A. I'd rather have more amperage capacity. Do solid state relays care
whether the load is DC or AC?
What think you all?
John
Message 5
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Rich and others:
Actually. Rick I ended up deciding there was ONE application for an
in-line "glass" fuse. That is the always LIVE when the Master Switch is
ON. I put my only in-line glass fuse immediately behind the top of the
firewall. It's hard to replace - but the hot wire is only several inches
long - with no chance to rub anything.
Ernest Kells RV-9A
----- Original Message -----
From: Rick and Sandra Lark
To: aeroelectric-list@matronics.com
Sent: Wednesday, July 15, 2009 10:06 PM
Subject: AeroElectric-List: glass fuses
That is really what you should be using (is ATO blade type fuses) over
the
>glass fuses. From our experience, using glass fuses has many
negatives and
>they aren't something we'd really recommend for airplanes anymore.
Bob> Absolutely! These have fragile internal connections at
the ends of the fusible links . . . they also used large
area, low pressure connections in their holders. Not
gas-tight.
Hi all: 1st time posting to this list.
Years ago I owned a "75 Celica GT that had an electric fuel pump. The
car kept quitting for no apparent reason (usually when my girlfriend
drove it). Ended up my favorite auto mechanic found the fuse end cap
was loose that fed the fuel pump. There is no way I would use glass
fuses for anything in an aircraft.
Regards
Rick Lark
Southampton, Ont
RV10
#40956
Message 6
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| Subject: | Re: Solid State Relays |
OK, I should've gone to the archives BEFORE I posted this thread.
But the objection 11/2 yrs ago was a voltage drop of 1.5 @ 12v. These
claim .35v @30V. Did the earlier versions claim a similarly low V drop?
I guess the only way to be sure is to buy one and test it.
JB
Message 7
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| Subject: | D.A.R question about fuse access |
Bob,
Too funny! So true - I have had the same experience in the Pitts - you
can feel when it's right. The Pitts will let you know when it's not. In
a Lanciar, I find it behaves best when flown by the numbers. I should
throw in a caveat of "the last standing instrument I'd enjoy having"
Remember, flying is easy - the plane will always go where you point it,
except when you are too slow. Don't do that.
Have a great day.
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Sent: Thursday, July 16, 2009 11:16 AM
Subject: Re: AeroElectric-List: D.A.R question about fuse access
At 05:25 PM 7/15/2009, you wrote:
Good Evening Glenn,
My primary instructor kept the airspeed covered up most of the time. I
learned to control airspeed via the sound and by the feel of the
controls.
Who needs an airspeed indicator?<G>
Only those not skilled in doing without them. When I
checked out new renters in our 150's I used to demonstrate
that "sticking the upper edge of the cowl on the
horizon" got you an 80 mph climb. I further demonstrated
that if the horizon is visible over the nose, you cannot
be too slow. After that, paying attention to power settings
pretty much covers the bases for not having an unhappy day
in the pattern.
I found this necessary/useful when new renters were
transitioning to an uncontrolled field sharing a 5
mile radius with 5 other uncontrolled fields. It was
a good idea to keep your eyes on the surrounding
environment as opposed to sticking the needles on some
finely tuned value for speeds and power.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 8
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| Subject: | Re: Solid State Relays |
If I read the data correctly, it appears these relays are only rated at 3A
continuous which even fairly small switches can handle. Not sure why
you'd pick the relay over a switch unless you wanted to use a micro-micro
switch to control something.
Also, a few other issues:
- It's rated for AC. Not sure how it will perform controlling a DC load.
- The forward voltage drop seems like it might be large - up to 1.5V at
peak current. Not only is that a bit of a performance hit, it will
generate some heat. The app notes specify to provide adequate
ventilation.
- Don't know what behavior you might see if the load tried to drive the
source - might not be bidirectional.
Regards,
Matt-
> Saw these
> http://www.futurlec.com/RelSS.shtml
> and for $20 they look like possible replacements for the common
> electro-mechanical relays that we now use. These are light, compact, and
very reliable. But I don't know if there are gradations of MOSFETs or if
they're just basic building blocks. The cost of these is about 1/8 of an
almost identical Teledyne unit and I wonder if "you get what you pay
for"
> is appropriate to apply here? Or is Teledyne just passing on the costs
of
> marketing, regulatory environment, lawyers, pensions, etc?
>
> The only obvious downside that is evident from the data sheet is that
the
> load capability starts falling off at about 60 deg C, so installation in
an engine compartment is off the table without a blast tube and
heatsink.
>
> One of these has a load spec of 240VAC @ 70A and another specs 100VDC @
40A. I'd rather have more amperage capacity. Do solid state relays care
whether the load is DC or AC?
>
> What think you all?
>
> John
>
>
Message 9
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| Subject: | Re: Solid State Relays |
I think you may have looked at the wrong part. You have to go down to
the bottom of the page to find the high amp rated DC units.
That said, see my previous email.
Dick Tasker
Matt Prather wrote:
>
> If I read the data correctly, it appears these relays are only rated at 3A
> continuous which even fairly small switches can handle. Not sure why
> you'd pick the relay over a switch unless you wanted to use a micro-micro
> switch to control something.
>
> Also, a few other issues:
>
> - It's rated for AC. Not sure how it will perform controlling a DC load.
> - The forward voltage drop seems like it might be large - up to 1.5V at
> peak current. Not only is that a bit of a performance hit, it will
> generate some heat. The app notes specify to provide adequate
> ventilation.
> - Don't know what behavior you might see if the load tried to drive the
> source - might not be bidirectional.
>
>
> Regards,
>
> Matt-
>
Message 10
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| Subject: | Re: Solid State Relays |
The 0.35V drop only applies to the low voltage assemblies which are not
listed at Futurlec. They only show the 100V and 200V for sale and they
have a much higher voltage drop at a lower current.
The 30V versions look very attractive with the 0.007 milliohm on
resistance at 50A.
However, they say nothing about reverse voltage, so I would have to
assume that these are only good for supplying power to a load and not
good for use where there could be a reverse voltage on them - such as
what would occur if you were trying to use two of these to switch two
different batteries to a common load.
Dick Tasker
John Burnaby wrote:
> OK, I should've gone to the archives BEFORE I posted this thread.
> But the objection 11/2 yrs ago was a voltage drop of 1.5 @ 12v. These
> claim .35v @30V. Did the earlier versions claim a similarly low V drop?
> I guess the only way to be sure is to buy one and test it.
>
> JB
Message 11
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| Subject: | Re: D.A.R question about fuse access |
Robert L. Nuckolls, III wrote:
> At 05:25 PM 7/15/2009, you wrote:
>> Good Evening Glenn,
>>
>> My primary instructor kept the airspeed covered up most of the time.
>> I learned to control airspeed via the sound and by the feel of the
>> controls.
>>
>> Who needs an airspeed indicator?<G>
>
> Only those not skilled in doing without them. When I
> checked out new renters in our 150's I used to demonstrate
> that "sticking the upper edge of the cowl on the
> horizon" got you an 80 mph climb. I further demonstrated
> that if the horizon is visible over the nose, you cannot
> be too slow. After that, paying attention to power settings
> pretty much covers the bases for not having an unhappy day
> in the pattern.
That instrument only works for people of the same height. It has to be
recalibrated for some of us 8*)
--
http://www.ernest.isa-geek.org
Message 12
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Ernest;
Why an inline "glass" fuse???? The ATO style fuse is a much better choice
with its one piece design, high pressure contacts etc. All the same reasons
that the automotive world went blade style to replace the "old technology"
"glass" fuses. No soldered end caps to come loose, no low pressure contacts
to corrode and fail. ATO/ATC is a much more reliable choice.
This holder is even waterproof. Good for 30A. http://tinyurl.com/l4eaae
Similar holders are available for the Maxi series as well if you require
higher ratings.
Bob McC
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest
Kells
Sent: Thursday, July 16, 2009 12:04 PM
Subject: Re: AeroElectric-List: glass fuses
Rich and others:
Actually. Rick I ended up deciding there was ONE application for an in-line
"glass" fuse. That is the always LIVE when the Master Switch is ON. I put my
only in-line glass fuse immediately behind the top of the firewall. It's
hard to replace - but the hot wire is only several inches long - with no
chance to rub anything.
Ernest Kells RV-9A
----- Original Message -----
From: Rick and Sandra Lark <mailto:jrlark@bmts.com>
Sent: Wednesday, July 15, 2009 10:06 PM
Subject: AeroElectric-List: glass fuses
That is really what you should be using (is ATO blade type fuses) over the
>glass fuses. From our experience, using glass fuses has many negatives and
>they aren't something we'd really recommend for airplanes anymore.
Bob> Absolutely! These have fragile internal connections at
the ends of the fusible links . . . they also used large
area, low pressure connections in their holders. Not
gas-tight.
Hi all: 1st time posting to this list.
Years ago I owned a "75 Celica GT that had an electric fuel pump. The car
kept quitting for no apparent reason (usually when my girlfriend drove it).
Ended up my favorite auto mechanic found the fuse end cap was loose that fed
the fuel pump. There is no way I would use glass fuses for anything in an
aircraft.
Regards
Rick Lark
Southampton, Ont
RV10
#40956
href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matro
nics.com/Navigator?AeroElectric-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
Message 13
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| Subject: | Situational awareness as an instrument of flight. |
>> Only those not skilled in doing without them. When I
>> checked out new renters in our 150's I used to demonstrate
>> that "sticking the upper edge of the cowl on the
>> horizon" got you an 80 mph climb. I further demonstrated
>> that if the horizon is visible over the nose, you cannot
>> be too slow. After that, paying attention to power settings
>> pretty much covers the bases for not having an unhappy day
>> in the pattern.
>That instrument only works for people of the same height. It has to
>be recalibrated for some of us 8*)
Yeah . . . that's why I was happy the thing averaged
80 . . .
Short guys IAS was a little slower, taller guys were
a little faster but rate of climb wasn't enough different
to worry about. Bottom line was that it kept the
guy's eyeballs out of the cockpit in the airport traffic
area.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
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