Today's Message Index:
----------------------
1. 06:19 AM - Re: Re: 12v vs 14v System? (Robert L. Nuckolls, III)
2. 11:20 AM - weird radio trouble (B Tomm)
3. 11:34 AM - Re: weird radio trouble (Earl Schroeder)
4. 11:55 AM - Re: weird radio trouble (Peter Pengilly)
5. 12:54 PM - Re: weird radio trouble (John MacCallum)
6. 01:22 PM - Re: weird radio trouble (BobsV35B@aol.com)
7. 01:43 PM - Re: weird radio trouble (David Lloyd)
8. 03:28 PM - Risks associated with unproven crimp tools . . . (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: 12v vs 14v System? |
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Re: 12v vs 14v System?
It's probably too much to ask for standard terms to be applied to
electrical systems after all these decades. [Wink]
Ain't gonna happen . . . batteries are chemical beasts with no
single cell offering anything closed to 12v. So combinations of
cells have to be joined until the target 'system' requirements
are met. In the case of lead-acid batteries, multiple cells in series
were '6-volt', '12-volt' and '24-volt' long before anyone stuck
them in a vehicle paired with a generator.
Early electrification of boats and railroad cars featured '32-volt
batteries' charged at 38 volts. To this day, you can still buy a 32
volt lamp for 'marine' applications.
Emacs!
Chas Kettering's 1916 Delco-Light plant for rural applications
were offered to
charge 16 lead-acid cells in series . . .
Emacs!
This would have nominally been a 32-volt battery charged by a generator
and (later a wind-mill) for a system voltage of 38 volts.
Just put a new battery in Dr. Dee's little red Saturn. Just for grins,
I sucked out most of the electrons in its off-the-shelf condition and
got this plot . . .
Emacs!
With a 5A load, you can see that it started out a closer to 13
volts and tossed
in the towel before it about 11 volts . . . with an AVERAGE output
of 12 volts.
Now, to stuff all those electrons back in at room temperature, I need
to charge it at 13.8 volts for a few days . . . but to stoke it back up in
hours or less, a charge voltage of 14.2 to 14.8 is called for. Since
day-one, vehicles of all stripe have been said to operate at the battery's
maintenance voltage (i.e. 14v) while in fact, batteries delivered energy at
their label value of 12v (which is a more of an average over the discharge
curve of the battery).
Now comes the lithium family of cells. If you charge a stack of 4 cells
to the maximum rated charge voltage of 4.2 volts per cell, then you'd
have to do it at about 16.8 volts. We might call this a '17 volt system.'
Emacs!
Referring to the family of curves above, the 16.8 volt operation
gives you a "15 volt battery". But put the same array of cells
into your "14v system" tuned to lead-acid chemistry and you get a
"13.5 volt battery" while giving up about 1/2 its max rated
chemical capacity.
Hence, it's entirely proper and logical to speak of batteries
in terms of the manner in which they deliver energy and to speak
of systems in terms a nominal operating voltage within which
all accessories (including the battery) are obliged to perform
to design goals.
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: | weird radio trouble |
A hangar neighbor did an engine overhaul last fall. The airplane didn't fly
for about 5 months. It sat in a hangar the whole time. Now that it's flying
again, there's a new weird radio problem that we can't figure out.
Initial radio operation (on the ground) is... not stellar but OK (maybe 4/5
for clarity). After airborne for a short time (less than 1/2 hour)
communications becomes so poor that radio contact with the tower cannot be
maintained.
Aircraft is BD4 (aluminum skins)
Comm antenna is on top ala Cessna 172 etc
The alternator is also new with the engine overhaul. Plane Power internally
regulated.
At first we thought it was a low battery (sitting for 5 months) or
alternator problem but a recently added multimeter reveals 14.5V while
flying.
The hangar has been very humid at times with condensation forming on all the
exterior surfaces. So we are wondering about corrosion or connection
issues. But comms on the ground are much better than in the air. That may
be just following the trend that initial communications is always better. It
seems to deteriorate a little after being airborne.
Any ideas?
Bevan
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: weird radio trouble |
Putting my money on 'ground' issues on aluminum skins. Even from one skin
to the next.
Good luck!
On Feb 16, 2015 1:25 PM, "B Tomm" <fvalarm@rapidnet.net> wrote:
>
>
> A hangar neighbor did an engine overhaul last fall. The airplane didn't
> fly for about 5 months. It sat in a hangar the whole time. Now that it's
> flying again, there's a new weird radio problem that we can't figure out.
>
> Initial radio operation (on the ground) is... not stellar but OK (maybe
> 4/5 for clarity). After airborne for a short time (less than 1/2 hour)
> communications becomes so poor that radio contact with the tower cannot be
> maintained.
>
> Aircraft is BD4 (aluminum skins)
> Comm antenna is on top ala Cessna 172 etc
>
> The alternator is also new with the engine overhaul. Plane Power
> internally regulated.
>
> At first we thought it was a low battery (sitting for 5 months) or
> alternator problem but a recently added multimeter reveals 14.5V while
> flying.
>
> The hangar has been very humid at times with condensation forming on all
> the exterior surfaces. So we are wondering about corrosion or connection
> issues. But comms on the ground are much better than in the air. That may
> be just following the trend that initial communications is always better.
> It seems to deteriorate a little after being airborne.
>
> Any ideas?
>
> Bevan
>
>
> *
>
>
> *
>
>
Message 4
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: weird radio trouble |
What type of radio?
On 16 Feb 2015 19:33, "B Tomm" <fvalarm@rapidnet.net> wrote:
>
>
> A hangar neighbor did an engine overhaul last fall. The airplane didn't
> fly for about 5 months. It sat in a hangar the whole time. Now that it's
> flying again, there's a new weird radio problem that we can't figure out.
>
> Initial radio operation (on the ground) is... not stellar but OK (maybe
> 4/5 for clarity). After airborne for a short time (less than 1/2 hour)
> communications becomes so poor that radio contact with the tower cannot be
> maintained.
>
> Aircraft is BD4 (aluminum skins)
> Comm antenna is on top ala Cessna 172 etc
>
> The alternator is also new with the engine overhaul. Plane Power
> internally regulated.
>
> At first we thought it was a low battery (sitting for 5 months) or
> alternator problem but a recently added multimeter reveals 14.5V while
> flying.
>
> The hangar has been very humid at times with condensation forming on all
> the exterior surfaces. So we are wondering about corrosion or connection
> issues. But comms on the ground are much better than in the air. That may
> be just following the trend that initial communications is always better.
> It seems to deteriorate a little after being airborne.
>
> Any ideas?
>
> Bevan
>
>
> *
>
>
> *
>
>
Message 5
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: | weird radio trouble |
You don=99t say whether it=99s a transmit or receive issue?
You also say contact with the tower, so do you mean local comms with a
control tower or do you
mean Air Traffic Control which is usually remote.
If on receive the Radio is a little scratchy and only readability 4 for
a local control tower there may be something wrong with the Antenna or
the feed line or the radio.
If you have more trouble receiving the further you get away from a local
station, ie a local Tower with weak reception and the Tower has trouble
hearing you, look at the Antenna and the Feedline,
check them for connections and check the SWR.
If Radio receives ok and the Antenna/feedline is ok but the Tower has
trouble hearing you at a distance then it=99s most likely the
Power output from the Radio. Most SWR Meters will also tell you
what the output power is so you can check that as well. Older model
Radios usually somewhere around 10 watts and the newer stuff 25 watts.
Cheers
John MacCallum
VH-DUU
RV 10 # 41016
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Peter
Pengilly
Sent: Tuesday, 17 February 2015 6:54 AM
Subject: Re: AeroElectric-List: weird radio trouble
What type of radio?
On 16 Feb 2015 19:33, "B Tomm" <fvalarm@rapidnet.net> wrote:
A hangar neighbor did an engine overhaul last fall. The airplane didn't
fly for about 5 months. It sat in a hangar the whole time. Now that
it's flying again, there's a new weird radio problem that we can't
figure out.
Initial radio operation (on the ground) is... not stellar but OK (maybe
4/5 for clarity). After airborne for a short time (less than 1/2 hour)
communications becomes so poor that radio contact with the tower cannot
be maintained.
Aircraft is BD4 (aluminum skins)
Comm antenna is on top ala Cessna 172 etc
The alternator is also new with the engine overhaul. Plane Power
internally regulated.
At first we thought it was a low battery (sitting for 5 months) or
alternator problem but a recently added multimeter reveals 14.5V while
flying.
The hangar has been very humid at times with condensation forming on all
the exterior surfaces. So we are wondering about corrosion or
connection issues. But comms on the ground are much better than in the
air. That may be just following the trend that initial communications
is always better. It seems to deteriorate a little after being airborne.
Any ideas?
Bevan
ist"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
Message 6
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: weird radio trouble |
Was the radio working acceptably before the engine work?
Old Bob
In a message dated 2/16/2015 1:35:01 P.M. Central Standard Time,
n233ee@gmail.com writes:
Putting my money on 'ground' issues on aluminum skins. Even from one
skin to the next.
Good luck!
On Feb 16, 2015 1:25 PM, "B Tomm" <_fvalarm@rapidnet.net_
(mailto:fvalarm@rapidnet.net) > wrote:
A hangar neighbor did an engine overhaul last fall. The airplane didn't
fly for about 5 months. It sat in a hangar the whole time. Now that it's
flying again, there's a new weird radio problem that we can't figure out.
Initial radio operation (on the ground) is... not stellar but OK (maybe
4/5 for clarity). After airborne for a short time (less than 1/2 hour)
communications becomes so poor that radio contact with the tower cannot be
maintained.
Aircraft is BD4 (aluminum skins)
Comm antenna is on top ala Cessna 172 etc
The alternator is also new with the engine overhaul. Plane Power
internally regulated.
At first we thought it was a low battery (sitting for 5 months) or
alternator problem but a recently added multimeter reveals 14.5V while flying.
The hangar has been very humid at times with condensation forming on all
the exterior surfaces. So we are wondering about corrosion or connection
issues. But comms on the ground are much better than in the air. That may
be just following the trend that initial communications is always better. It
seems to deteriorate a little after being airborne.
Any ideas?
Bevan
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com _blank">http://www.matronics.com/contribution
Message 7
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: weird radio trouble |
First, suggest checking the coax cable from the antenna to the radio and
also the BNC connectors of both ends which might have a broken shield
connection or cold solder joint. The coax cable should be checked to
see if it got pinched, nibbled on by mice, cut, water in the dielectric,
etc
D
-------------------------------------------------------------------------
-------
----- Original Message -----
From: BobsV35B@aol.com
To: aeroelectric-list@matronics.com
Sent: Monday, February 16, 2015 1:21 PM
Subject: Re: AeroElectric-List: weird radio trouble
Was the radio working acceptably before the engine work?
Old Bob
In a message dated 2/16/2015 1:35:01 P.M. Central Standard Time,
n233ee@gmail.com writes:
Putting my money on 'ground' issues on aluminum skins. Even from
one skin to the next.
Good luck!
On Feb 16, 2015 1:25 PM, "B Tomm" <fvalarm@rapidnet.net> wrote:
A hangar neighbor did an engine overhaul last fall. The airplane
didn't fly for about 5 months. It sat in a hangar the whole time. Now
that it's flying again, there's a new weird radio problem that we can't
figure out.
Initial radio operation (on the ground) is... not stellar but OK
(maybe 4/5 for clarity). After airborne for a short time (less than 1/2
hour) communications becomes so poor that radio contact with the tower
cannot be maintained.
Aircraft is BD4 (aluminum skins)
Comm antenna is on top ala Cessna 172 etc
The alternator is also new with the engine overhaul. Plane Power
internally regulated.
At first we thought it was a low battery (sitting for 5 months) or
alternator problem but a recently added multimeter reveals 14.5V while
flying.
The hangar has been very humid at times with condensation forming
on all the exterior surfaces. So we are wondering about corrosion or
connection issues. But comms on the ground are much better than in the
air. That may be just following the trend that initial communications
is always better. It seems to deteriorate a little after being airborne.
Any ideas?
Bevan
ist"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
List
href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.
matronics.com/Navigator?AeroElectric-List
ms.matronics.com/">http://forums.matronics.com
tp://www.matronics.com/contribution">http://www.matronics.com/contributio
n
Message 8
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: | Risks associated with unproven crimp tools . . . |
A few days ago I received some wire segments off of
an airplane that experienced burned p-lead shields,
melted insulation around center conductors AND even
failure of toggle switch.
The problem manifested in the airplane when the toggle
switch(es) failed open after 100+ hours of service.
Only after second failures of switches did more detailed
examination reveal melted insulation over outer jacket
of p-lead shields as well as melted insulation around
center conductor.
This had the 'smell' of a sneak-path ground consisting
of (1) a poor architecture of the p-lead wiring and
(2) high resistance in the starter current ground
path.
The jumper between forest of tabs ground on fire wall
hand been fabricated with a less than ideal crimp
tool.
Emacs!
I did some voltage drop tests across the crimp joints and
found pretty high . . . about 2.5 millivolts at only 10 amps!
Emacs!
Cross-sectioned crimp joints examined under the microscope
showed numerous areas of 'failure to achieve gas tight' across
the face of the cut.
Emacs!
My findings suggest some value in replacement of all terminals
applied with this tooling. I am also concerned with the corrosion
ring around the hole in the terminal . . . this should at worst
be slightly darkened tin plating. The degree of corrosion and
pitting of the mating surface suggests that this terminal was
not made-up with sufficient force to achieve gas-tightness
in the joint.
If you don't have access to a hydraulic tool and proven die
to install a terminal, then consider soldering your terminals
on per the article at:
http://tinyurl.com/qh4k7ko
Interestingly enough, it was failure of magneto p-lead switches
that brought the deficiency to light.
Emacs!
As you can see above, the phosphor bronze rocker strut that held
the moving contact was burned in two. The fixed contact is in great
shape but structure that supported the moving contact fused.
The moving contact was free to rattle around inside the switch.
If you use welding cable for your fat-wires, the weld shop
where you bought the wire can probably sell you terminals and
install them with proven tools.
Finally, make sure all mating surfaces for bolted up
joints are clean, smooth and torqued down right smartly
on assembly. This is an excellent example of a case where
marginal joint(s) took perhaps years before degrading to
the point where smoke and/or failure to perform manifested.
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! --
|