Today's Message Index:
----------------------
1. 07:13 AM - Re: (Ken)
2. 07:39 AM - Re: (Bill Watson)
3. 08:59 AM - Electrical Gremlins (jonlaury)
4. 09:14 AM - Re: (Bob Meyers)
5. 12:30 PM - Electrical Gremlins (jonlaury)
6. 01:53 PM - Re: Noise in damp weather (chinesespaceman)
7. 05:41 PM - Wire Bundle Wrapping Tape? (Jon McLin)
8. 09:40 PM - Re: Wire Bundle Wrapping Tape? (halbenjamin@optonline.net)
Message 1
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| Subject: | Re: ectric-List: |
Thank you Bob and Paul for taking the time to point this out
and correct my understanding.
The documentation that I have is incomplete and I believed it without
thinking it through. It may not have any external magnetic sensor but I
agree that it must at least have an unmentioned internal sensor.
Ken
On 12/01/2012 8:10 PM, Bob Meyers wrote:
> --> AeroElectric-List message posted by: Bob
> Meyers<bobmeyers@meyersfamily.org>
>
> No, you're missing the heading. Your lookup table is just giving you
> the magnetic adjustment to a 'true' track. Most GPS's do just that
> when you tell them you want a magnetic track.
>
> You said your aircraft has no access to magnetic information. Without
> that it can't tell your plane is pointing in a direction other than
> the ground track - magnetic or not. Your heading will only match your
> track in no wind conditions.
>
> You still need something to tell you which way the plane is pointing,
> not tracking. However if the EFIS has access to magnetic heading
> data, then you can calculate wind speed and direction in the EFIS.
>
> Bob Meyers
>
> Flying my Sonex N982SX - Building log at http://n982sx.com
>
> Sent from my iPad
>
> On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman@albedo.net>
> wrote:
>
>> --> AeroElectric-List message posted by: "Ken
>> Lehman"<klehman@albedo.net>
>>
>> Hello Paul
>>
>> The GPS gives groundspeed, track, and position. You can go into a
>> lookup table to find the magnetic variation at your position. If
>> you know the TAS because you have pitot static info and
>> temperature, you should be able to solve for the wind vector I
>> believe. Same as can be done with an E6B computer. I think it goes
>> heading vector plus wind vector equals track vector. So if you know
>> any two vectors you can compute the third vector.
>>
>> Mostly I was just pointing out that many glass PFD/ADI systems
>> already have all the sensor info they need to display a magnetic
>> heading if the designer wishes to display it. I often fly an
>> aircraft that does just that. It has no magnetic sensors but it
>> computes and displays magnetic heading.
>>
>> Of course variation does change slightly over a multi year period
>> so minor changes in the lookup table might be appropriate every few
>> years if high accuracy is desired.
>>
>> Ken
>>
>>> --> AeroElectric-List message posted by: Paul
>>> Millner<millner@me.com> S>
>>>
>>> On 1/4/2012 7:55 AM, Ken Lehman wrote:
>>>> Some rnav units that have airspeed inputs calculate drift and
>>>> simply use a lookup table to convert track to magnetic dg
>>>> info.
>>> How would that work, Ken? Seems like knowing only airspeed and
>>> groundspeed, you don't know if the headwind/tailwind component
>>> is directly ahead/behind you or off a wingtip... so how does
>>> airspeed and groundspeed and track allow you to calculate
>>> heading?
>>>
>>> Paul
>>>
Message 2
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| Subject: | Re: ectric-List: |
FWIW, I recently confirmed that accurate calibration of the mag sensor has a significant
impact on wind calculations. After carefully running the calibration
routine on my GRT EFIS, the displayed wind direction and speeds are now spot
on.
Bill
Sent from my iPad
On Jan 14, 2012, at 10:10 AM, Ken <klehman@albedo.net> wrote:
>
> Thank you Bob and Paul for taking the time to point this out
> and correct my understanding.
>
> The documentation that I have is incomplete and I believed it without thinking
it through. It may not have any external magnetic sensor but I agree that it
must at least have an unmentioned internal sensor.
>
> Ken
>
> On 12/01/2012 8:10 PM, Bob Meyers wrote:
>> --> AeroElectric-List message posted by: Bob
>> Meyers<bobmeyers@meyersfamily.org>
>>
>> No, you're missing the heading. Your lookup table is just giving you
>> the magnetic adjustment to a 'true' track. Most GPS's do just that
>> when you tell them you want a magnetic track.
>>
>> You said your aircraft has no access to magnetic information. Without
>> that it can't tell your plane is pointing in a direction other than
>> the ground track - magnetic or not. Your heading will only match your
>> track in no wind conditions.
>>
>> You still need something to tell you which way the plane is pointing,
>> not tracking. However if the EFIS has access to magnetic heading
>> data, then you can calculate wind speed and direction in the EFIS.
>>
>> Bob Meyers
>>
>> Flying my Sonex N982SX - Building log at http://n982sx.com
>>
>> Sent from my iPad
>>
>> On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman@albedo.net>
>> wrote:
>>
>>> --> AeroElectric-List message posted by: "Ken
>>> Lehman"<klehman@albedo.net>
>>>
>>> Hello Paul
>>>
>>> The GPS gives groundspeed, track, and position. You can go into a
>>> lookup table to find the magnetic variation at your position. If
>>> you know the TAS because you have pitot static info and
>>> temperature, you should be able to solve for the wind vector I
>>> believe. Same as can be done with an E6B computer. I think it goes
>>> heading vector plus wind vector equals track vector. So if you know
>>> any two vectors you can compute the third vector.
>>>
>>> Mostly I was just pointing out that many glass PFD/ADI systems
>>> already have all the sensor info they need to display a magnetic
>>> heading if the designer wishes to display it. I often fly an
>>> aircraft that does just that. It has no magnetic sensors but it
>>> computes and displays magnetic heading.
>>>
>>> Of course variation does change slightly over a multi year period
>>> so minor changes in the lookup table might be appropriate every few
>>> years if high accuracy is desired.
>>>
>>> Ken
>>>
>>>> --> AeroElectric-List message posted by: Paul
>>>> Millner<millner@me.com> S>
>>>>
>>>> On 1/4/2012 7:55 AM, Ken Lehman wrote:
>>>>> Some rnav units that have airspeed inputs calculate drift and
>>>>> simply use a lookup table to convert track to magnetic dg
>>>>> info.
>>>> How would that work, Ken? Seems like knowing only airspeed and
>>>> groundspeed, you don't know if the headwind/tailwind component
>>>> is directly ahead/behind you or off a wingtip... so how does
>>>> airspeed and groundspeed and track allow you to calculate
>>>> heading?
>>>>
>>>> Paul
>>>>
>
>
>
>
Message 3
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| Subject: | Electrical Gremlins |
1.) I installed an EyeBeam Mini as a cabin light. It's in a housing that also contains
the radio speaker. It gets its power from the battery bus.
Whenever I turn on the PS Engineering 7000B audio panel, or key the mike, the EBM
starts flashing and is unresponsive to its on/off switch or built-in dimmer.
The only way to get it to stop is to pull the power.
The dimming/switching are by capacitance sensing (touch). Everything in the airplane
is connected to a single point ground.
Suggestions much appreciated
:D
2.) I installed an AEC 9005 LVW module per instructions but the LVW lamp flashes
(blinking LED) when I power the system from my bench 13.6v power supply.
3.) Same as 2 above for my B&C LR3 regulator. I did all of their troubleshooting
diagnostics and everything was to spec.
Thanks for any help,
John
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363739#363739
Message 4
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| Subject: | Re: ectric-List: |
Hi Ken,
Yes, you probably have an internal compass.
I assume you don't have an inertial navigation system with ring laser gyros!!!
Not too many of those in the OBAM market. The accelerometers and gyro pkgs in our
EFIS units are pretty good though.
Bob Meyers
Flying my Sonex N982SX - Building log at http://n982sx.com
Sent from my iPad
On Jan 14, 2012, at 9:10 AM, Ken <klehman@albedo.net> wrote:
>
> Thank you Bob and Paul for taking the time to point this out
> and correct my understanding.
>
> The documentation that I have is incomplete and I believed it without thinking
it through. It may not have any external magnetic sensor but I agree that it
must at least have an unmentioned internal sensor.
>
> Ken
>
> On 12/01/2012 8:10 PM, Bob Meyers wrote:
>> --> AeroElectric-List message posted by: Bob
>> Meyers<bobmeyers@meyersfamily.org>
>>
>> No, you're missing the heading. Your lookup table is just giving you
>> the magnetic adjustment to a 'true' track. Most GPS's do just that
>> when you tell them you want a magnetic track.
>>
>> You said your aircraft has no access to magnetic information. Without
>> that it can't tell your plane is pointing in a direction other than
>> the ground track - magnetic or not. Your heading will only match your
>> track in no wind conditions.
>>
>> You still need something to tell you which way the plane is pointing,
>> not tracking. However if the EFIS has access to magnetic heading
>> data, then you can calculate wind speed and direction in the EFIS.
>>
>> Bob Meyers
>>
>> Flying my Sonex N982SX - Building log at http://n982sx.com
>>
>> Sent from my iPad
>>
>> On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman@albedo.net>
>> wrote:
>>
>>> --> AeroElectric-List message posted by: "Ken
>>> Lehman"<klehman@albedo.net>
>>>
>>> Hello Paul
>>>
>>> The GPS gives groundspeed, track, and position. You can go into a
>>> lookup table to find the magnetic variation at your position. If
>>> you know the TAS because you have pitot static info and
>>> temperature, you should be able to solve for the wind vector I
>>> believe. Same as can be done with an E6B computer. I think it goes
>>> heading vector plus wind vector equals track vector. So if you know
>>> any two vectors you can compute the third vector.
>>>
>>> Mostly I was just pointing out that many glass PFD/ADI systems
>>> already have all the sensor info they need to display a magnetic
>>> heading if the designer wishes to display it. I often fly an
>>> aircraft that does just that. It has no magnetic sensors but it
>>> computes and displays magnetic heading.
>>>
>>> Of course variation does change slightly over a multi year period
>>> so minor changes in the lookup table might be appropriate every few
>>> years if high accuracy is desired.
>>>
>>> Ken
>>>
>>>> --> AeroElectric-List message posted by: Paul
>>>> Millner<millner@me.com> S>
>>>>
>>>> On 1/4/2012 7:55 AM, Ken Lehman wrote:
>>>>> Some rnav units that have airspeed inputs calculate drift and
>>>>> simply use a lookup table to convert track to magnetic dg
>>>>> info.
>>>> How would that work, Ken? Seems like knowing only airspeed and
>>>> groundspeed, you don't know if the headwind/tailwind component
>>>> is directly ahead/behind you or off a wingtip... so how does
>>>> airspeed and groundspeed and track allow you to calculate
>>>> heading?
>>>>
>>>> Paul
>>>>
>
>
>
>
>
Message 5
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| Subject: | Electrical Gremlins |
EyeBeam Mini URL:
http://aveogroup.com/aveoshop/product.php?id_product=40
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363764#363764
Message 6
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| Subject: | Re: Noise in damp weather |
Guys, thanks for the input.
Given that the battery was too low today to crank the motor, I guess the voltage
was indeed low at the end of the last flight. I have listed below the checks
I made and corrections before flying today. (it was -5.5C this morning here
in the UK)
My aircraft has a cable operated master switch that serves to break the negative
lead from the battery. It has a 30Amp B&C Alternator, that feeds 3 phase to
the regulator rectifier:
Flew today and made a few tests and observations.
I haven't as yet checked the battery.
When I arrived I checked all the terminals and connections related to the alternator.
Tightened the screws that secure the DC + and - through the large capacitor. They
weren't hanging off, but not as tight as should have been.
There was a very loose connection from 1 of the output phases into the fuse box.
I checked and tightened up all of the terminals of the 3 phase output each side
of their fuses.
Battery terminals both secure. Earth lead battery to negative master switch secure.
Main earth lead from forest of earth on firewall to engine mount secure and
clean.
Checked the negative master switch (cable operated) to ensure it was functioning
correctly, all appeared good, with no high resistance when closed.
No continuity through the master switch when open.
Hand to hand start the engine as the battery was a bit low, I expect it hasn't
been charging on the return leg of it's last journey due to the loose connection
from the alternator.
Flew for total of 1:20 without any electrical issues, turning lights on etc did
not cause any noise.
When landed and parked up, I pulled the master switch while the engine was running.
Got a severe noise blast through the headsets via the intercom. This got
worse if I turned for example the nav lights on. If I switched the alternator
off by it's switch then all went quiet.
Battery voltage after flight was 13.7 volts. I measured the voltage between battery
+ and the - after the master switch and that too was 13.7v, so doesn't seem
to be a master switch problem.
I am guessing that when I disconnect the master switch, i.e. the primary earth
return, then there still exists an earth return through the panel, cable outers
etc. However, even if they make their way back to the engine, the negative master
switch should prevent it getting back to the battery? So, the current from
the alternator is somehow providing electrical power + and - even with the
master switch off?
When I got the aircraft all of the earths ran everywhere, lots through the panel,
mostly low current stuff like fuel gauges etc. There are still some of these
remaining, although 90% + do run to the forest of earth inside the firewall.
With the engine off and the master switch turned off, there is no current flow.
Maybe I don't have anything to worry about?
Your thoughts appreciated
Gavin
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363769#363769
Message 7
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| Subject: | Wire Bundle Wrapping Tape? |
Wire bundles in my Cessna are in some places spiral wrapped in a white translucent
tape. The tape is not the plastic spiral wrap that is commonly available
for wire harnesses; nor is it regular electrical tape. The thickness and "stickiness"
is somewhere in between - the tape sticks to itself enough that the wrap
holds, but it can be readily unwrapped. It's roughly 1" wide. I estimate
the thickness at somewhere between 5 and 10 mils.
What is this, and where can I purchase some?
Thanks,
Jon McLin
Message 8
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| Subject: | Re: Wire Bundle Wrapping Tape? |
Jon,
Sounds like Silicone tape. (aka rescue tape) Aircraft Spruce carries it. Good luck!
Hal Benjamin - RV-4
Long Island, NY
Starting engine soon - Should be flying this year!
----- Original Message -----
From: Jon McLin
Subject: AeroElectric-List: Wire Bundle Wrapping Tape?
>
> Wire bundles in my Cessna are in some places spiral wrapped in a
> white translucent tape. The tape is not the plastic spiral wrap
> that is commonly available for wire harnesses; nor is it regular
> electrical tape. The thickness and "stickiness" is somewhere in
> between - the tape sticks to itself enough that the wrap holds,
> but it can be readily unwrapped. It's roughly 1" wide. I
> estimate the thickness at somewhere between 5 and 10 mils.
>
> What is this, and where can I purchase some?
>
> Thanks,
> Jon McLin
>
>
>
>
>
>
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