Today's Message Index:
----------------------
0. 12:24 AM - PLEASE READ - Matronics Email List Fund Raiser During November! (Matt Dralle)
1. 01:50 AM - Re: MT Props (FLYaDIVE)
2. 04:05 AM - Re: MT Props (Airport Bum)
3. 07:00 AM - Re: MT Props (FLYaDIVE)
4. 08:14 AM - Re: MT Props (Airport Bum)
5. 08:29 AM - Re: MT Props (FLYaDIVE)
6. 08:53 AM - Re: MT Props (Airport Bum)
7. 05:26 PM - Re: MT Props (Gary L Vogt)
Message 0
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| Subject: | PLEASE READ - Matronics Email List Fund Raiser During |
November!
Dear Listers,
Each November I hold a PBS-like fund raiser to support the continued operation
and upgrade of the Email List and Fourm Services at Matronics. It's solely through
the Contributions of List members (you) that these Matronics Lists are possible.
You have probably noticed that there are no banner ads or pop-up windows on any of the Matronics Lists or related web sites such as the Forums site http://forums.matronics.com , Wiki site http://wiki.matronics.com , or other related pages such as the List Search Engine http://www.matronics.com/search , List Browse http://www.matronics.com/listbrowse , etc. This is because I believe in a List experience that is completely about the sport we all enjoy - namely Airplanes and not about annoying advertisements.
During the month of November I will be sending out List messages every couple of
days reminding everyone that the Fund Raiser is underway. I ask for your patience
and understanding during the Fund Raiser and throughout these regular messages.
The Fund Raiser is only financial support mechanism I have to pay all
of the bills associated with running these lists. YOUR personal Contribution
counts!
This year we have a really HUGE and TERRIFIC line up of free gifts to go along
with the various Contribution levels. In fact, there are over 30 different gifts
to choose from - more than we've ever had before! There's something for everyone,
to be sure. Most all of these gifts have been provided by some of the
vary members and vendors that you'll find on the Matronics Lists and they have
been either donated or provided at substantially discounted rates.
This year, these generous members include:
Andy Gold of the Builder's Bookstore http://www.buildersbooks.com
Bob Nuckolls of the AeroElectric Connection http://www.aeroelectric.com
Corbin Glowacki of My Pilot Store http://www.mypilotstore.com
George Race of Race Consulting http://www.mrrace.com/
Jon Croke of HomebuiltHELP http://www.homebuilthelp.com
These are very generous guys and I encourage you to visit their respective web
sites. Each one offers a unique and excellent aviation-related product line.
I would like publicly to thank Andy, Bob, Corbin, George, and Jon their generous
support of the Lists again this year!!
Please make your List Contribution using any one of three secure methods including
using a credit card, PayPal, or by personal check. All three methods afford
you the opportunity to select one of this year's free gifts with a qualifying
Contribution amount!!
To make your Contribution, please visit the secure web site:
http://www.matronics.com/contribution
I would like to thank everyone in advance for their generous financial AND moral
support over the years!
Thank you!
Matt Dralle
Matronics Email List Administrator
RV-4/RV-6/RV-8 Builder/Rebuilder/Pilot
Message 1
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Melted Block, Roger.
MT chose the wrong material for the the insulation block. AND they did not
use a large enough brush system. One brush failed, guessing here, probably
by the copper braid loosing connection. This caused a high resistance and
a higher current through that brushes spring which, is not copper - ergo
still higher resistance , which caused the spring to heat up and melted the
plastic.
*Barry*
*=93Chop=92d Liver=94*
NJ has taken the next step. They are identifying cars with bad drivers.
You will notice some cars with a large red "R" on them. That is to
identify the drivers as "R"estricted. Restricted is just a polite way of
saying Bad Drivers. Be cautious around them.
On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
> Gary: So what is that goo on the right spring that's still in the unit?
> Roger Rucker
> AA5A '78 HWO
> -----Original Message-----
> From: Gary L Vogt <teamgrumman@yahoo.com>
> To: Teamgrumman List <teamgrumman-list@matronics.com>
> Sent: Fri, Nov 1, 2013 12:13 am
> Subject: TeamGrumman-List: MT Props
>
> I was going to post this on GG but realized I can't post pics.
>
> This is the second brush block installed on this plane. The first one
> failed in less than 100 hours. This one failed in less than 90 hours.
>
> It isn't a well designed piece of hardware.
>
> Gary
>
> *
>
===========
===========
===========
>
>
Message 2
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Barry,
You may have shed some light on the issue. Not knowing what year the tiger i
s, is it possible that the part is the wrong part number? Could that be the
part for a 24 volt system and it is failing with double the amps at 12 volt
s? I don't recall this failure being discussed previously by any of those w
ith the mt. Also wondering if there could be a ground issue (bad ground) in
the circuit somewhere causing resistance which is causing a heat build up i
n this part?
Kevin
On Nov 1, 2013, at 3:49 AM, FLYaDIVE <flyadive@gmail.com> wrote:
> Melted Block, Roger.
>
> MT chose the wrong material for the the insulation block. AND they did not
use a large enough brush system. One brush failed, guessing here, probably
by the copper braid loosing connection. This caused a high resistance and a
higher current through that brushes spring which, is not copper - ergo stil
l higher resistance , which caused the spring to heat up and melted the plas
tic.
>
>
>
> *Barry*
> *=9CChop=99d Liver=9D*
>
> NJ has taken the next step. They are identifying cars with bad drivers. Y
ou will notice some cars with a large red "R" on them. That is to identify
the drivers as "R"estricted. Restricted is just a polite way of saying Bad
Drivers. Be cautious around them.
>
>
> On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
>> Gary: So what is that goo on the right spring that's still in the unit?
>> Roger Rucker
>> AA5A '78 HWO
>> -----Original Message-----
>> From: Gary L Vogt <teamgrumman@yahoo.com>
>> To: Teamgrumman List <teamgrumman-list@matronics.com>
>> Sent: Fri, Nov 1, 2013 12:13 am
>> Subject: TeamGrumman-List: MT Props
>>
>> I was going to post this on GG but realized I can't post pics.
>>
>> This is the second brush block installed on this plane. The first one fa
iled in less than 100 hours. This one failed in less than 90 hours.
>>
>> It isn't a well designed piece of hardware.
>>
>> Gary
>>
>>
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> ="_blank">www.mypilotstore.com
>> ank">www.mrrace.com
>> _blank">http://www.matronics.com/contribution
>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List
>> tp://forums.matronics.com
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
Message 3
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Kevin:
Is this your plane?
I do not have enough pictures and I wish I could check the hardness of the
material (Durometer) but yes, there are lots more questions that could come
up:
Question: Is this a dual brush system? Meaning two (2) brushes for each
side of the connection. In a dual brush system the a single brush is
usually chosen to handle 100% of the current Plus a safety margin of 50%
more. In this case the individual size of the brush is too small. But
therein lies the rub (Hamlet). You would go to a dual brush system because
of space and/or cost of a large brush. They did not have the space for a
Large one brush system.
There is also the idea of redundancy - If one brush should fail you would
want to still have control over the prop.
Ever notice in Motor Designs [look at a good quality electric drill] the
Brush Runs Inside a METAL sleeve or Bakelite (not feasible in aircraft due
to its brittleness) . This sleeve offers a lower coefficient of friction
[Nylon and machined plastics; even Teflon have a very high coefficient of
friction] for the sliding brush, an alternate current path, as well as
cooling [heatsink] for the brushes. MT lost sight of the requirements.
Getting back to your question Kevin:
Yes, a bad ground or any bad connection in the MT system could cause high
current.
To answer a question before asked: Shouldn't the CARBON of the brush help
lower the coefficient of friction? YES, to some extent but the friction
will wear away the carbon as well.
But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect,
you just have things reversed. If you INCREASE the Voltage (Double in this
case) you DECREASE the Current (It would draw 1/2 the current in this
case).
Power (Watts) = I x E
Lets say the system draws 200 Watts
200 Watts / 12 Volts = 16.66 Amps
Now you up the voltage...
200 Watts / 24 Volts = 8.33 Amps
I just had an appfinity - What if you installed an AMMETER in the circuit.
You should be able to monitor the condition of the brushes. As the
brushes deteriorate the current would go up. Set a Delta for how much is
acceptable and of course if a brush totally fails the current would jump.
Gary - Being there is such a short life cycle [MTBF], this sure sounds like
AD material and a phone call to MT is in order.
*Barry*
*=93Chop=92d Liver=94*
NJ has taken the next step. They are identifying cars with bad drivers.
You will notice some cars with a large red "R" on them. That is to
identify the drivers as "R"estricted. Restricted is just a polite way of
saying Bad Drivers. Be cautious around them.
On Fri, Nov 1, 2013 at 7:04 AM, Airport Bum <aa5_driver@yahoo.com> wrote:
> Barry,
>
> You may have shed some light on the issue. Not knowing what year the
> tiger is, is it possible that the part is the wrong part number? Could
> that be the part for a 24 volt system and it is failing with double the
> amps at 12 volts? I don't recall this failure being discussed previously
> by any of those with the mt. Also wondering if there could be a ground
> issue (bad ground) in the circuit somewhere causing resistance which is
> causing a heat build up in this part?
>
> Kevin
>
> On Nov 1, 2013, at 3:49 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>
> Melted Block, Roger.
>
> MT chose the wrong material for the the insulation block. AND they did no
t
> use a large enough brush system. One brush failed, guessing here, probab
ly
> by the copper braid loosing connection. This caused a high resistance an
d
> a higher current through that brushes spring which, is not copper - ergo
> still higher resistance , which caused the spring to heat up and melted t
he
> plastic.
>
>
> *Barry*
> *=93Chop=92d Liver=94*
>
> NJ has taken the next step. They are identifying cars with bad drivers.
> You will notice some cars with a large red "R" on them. That is to
> identify the drivers as "R"estricted. Restricted is just a polite way of
> saying Bad Drivers. Be cautious around them.
>
>
> On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
>
>> Gary: So what is that goo on the right spring that's still in the unit
?
>> Roger Rucker
>> AA5A '78 HWO
>> -----Original Message-----
>> From: Gary L Vogt <teamgrumman@yahoo.com>
>> To: Teamgrumman List <teamgrumman-list@matronics.com>
>> Sent: Fri, Nov 1, 2013 12:13 am
>> Subject: TeamGrumman-List: MT Props
>>
>> I was going to post this on GG but realized I can't post pics.
>>
>> This is the second brush block installed on this plane. The first one
>> failed in less than 100 hours. This one failed in less than 90 hours.
>>
>> It isn't a well designed piece of hardware.
>>
>> Gary
>>
>> *
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> ="_blank">www.mypilotstore.com
>> ank">www.mrrace.com
>> _blank">http://www.matronics.com/contribution
>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-Lis
t
>> tp://forums.matronics.com*
>>
>>
> *
>
> ========================
===========ctric.com
> >www.buildersbooks.comuilthelp.comotstore.com
> matronics.com/contribution
> ========================
> t">http://www.matronics.com/Navigator?TeamGrumman-List
> ========================
===========cs.com
> ========================
===========*
>
> *
>
>
===========
===========
===========
>
============*
>
>
Message 4
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Barry,
I think you mis read my post. I stated...
"Not knowing what year the tiger is, is it possible that the part is the wro
ng part number? Could that be the part for a 24 volt system and it is faili
ng with double the amps at 12 volts?"
And you replied...
"But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect, yo
u just have things reversed. If you INCREASE the Voltage (Double in this ca
se) you DECREASE the Current (It would draw 1/2 the current in this case). P
ower (Watts) = I x E
Lets say the system draws 200 Watts
>
> 200 Watts / 12 Volts = 16.66 Amps
> Now you up the voltage...
> 200 Watts / 24 Volts = 8.33 Amps"
Yes, I know that 24 volts requires half the amps of 12 volts, or inversely, 1
2 volts takes twice the amps as 24 volts. That is why I asked if it was a 2
4 volt part being used in a 12 volt system that was causing the failure.
No it's not my plane, but the prop interests me. I'd like to see the mount f
or the brushes as well as the harness. I'm wondering how much of this is fa
ctory parts vs how much is supplied/made by the installer?
Any other ideas? Are any other mt users experiencing this issue?
Kevin
On Nov 1, 2013, at 9:00 AM, FLYaDIVE <flyadive@gmail.com> wrote:
> Kevin:
>
> Is this your plane?
>
> I do not have enough pictures and I wish I could check the hardness of the
material (Durometer) but yes, there are lots more questions that could come
up:
> Question: Is this a dual brush system? Meaning two (2) brushes for each s
ide of the connection. In a dual brush system the a single brush is usually
chosen to handle 100% of the current Plus a safety margin of 50% more. In t
his case the individual size of the brush is too small. But therein lies th
e rub (Hamlet). You would go to a dual brush system because of space and/or
cost of a large brush. They did not have the space for a Large one brush s
ystem.
> There is also the idea of redundancy - If one brush should fail you would w
ant to still have control over the prop.
>
> Ever notice in Motor Designs [look at a good quality electric drill] the B
rush Runs Inside a METAL sleeve or Bakelite (not feasible in aircraft due to
its brittleness) . This sleeve offers a lower coefficient of friction [Nyl
on and machined plastics; even Teflon have a very high coefficient of fricti
on] for the sliding brush, an alternate current path, as well as cooling [he
atsink] for the brushes. MT lost sight of the requirements.
>
> Getting back to your question Kevin:
> Yes, a bad ground or any bad connection in the MT system could cause high c
urrent.
>
> To answer a question before asked: Shouldn't the CARBON of the brush help
lower the coefficient of friction? YES, to some extent but the friction wi
ll wear away the carbon as well.
>
> But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect, y
ou just have things reversed. If you INCREASE the Voltage (Double in this c
ase) you DECREASE the Current (It would draw 1/2 the current in this case).
> Power (Watts) = I x E
> Lets say the system draws 200 Watts
> 200 Watts / 12 Volts = 16.66 Amps
> Now you up the voltage...
> 200 Watts / 24 Volts = 8.33 Amps
>
> I just had an appfinity - What if you installed an AMMETER in the circuit.
You should be able to monitor the condition of the brushes. As the brushe
s deteriorate the current would go up. Set a Delta for how much is acceptab
le and of course if a brush totally fails the current would jump.
>
> Gary - Being there is such a short life cycle [MTBF], this sure sounds lik
e AD material and a phone call to MT is in order.
>
>
> *Barry*
> *=9CChop=99d Liver=9D*
>
> NJ has taken the next step. They are identifying cars with bad drivers. Y
ou will notice some cars with a large red "R" on them. That is to identify
the drivers as "R"estricted. Restricted is just a polite way of saying Bad
Drivers. Be cautious around them.
>
>
> On Fri, Nov 1, 2013 at 7:04 AM, Airport Bum <aa5_driver@yahoo.com> wrote:
>> Barry,
>>
>> You may have shed some light on the issue. Not knowing what year the tig
er is, is it possible that the part is the wrong part number? Could that be
the part for a 24 volt system and it is failing with double the amps at 12 v
olts? I don't recall this failure being discussed previously by any of thos
e with the mt. Also wondering if there could be a ground issue (bad ground)
in the circuit somewhere causing resistance which is causing a heat build u
p in this part?
>>
>> Kevin
>>
>> On Nov 1, 2013, at 3:49 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>>
>>> Melted Block, Roger.
>>>
>>> MT chose the wrong material for the the insulation block. AND they did n
ot use a large enough brush system. One brush failed, guessing here, probab
ly by the copper braid loosing connection. This caused a high resistance an
d a higher current through that brushes spring which, is not copper - ergo s
till higher resistance , which caused the spring to heat up and melted the p
lastic.
>>>
>>>
>>>
>>> *Barry*
>>> *=9CChop=99d Liver=9D*
>>>
>>> NJ has taken the next step. They are identifying cars with bad drivers.
You will notice some cars with a large red "R" on them. That is to ident
ify the drivers as "R"estricted. Restricted is just a polite way of saying B
ad Drivers. Be cautious around them.
>>>
>>>
>>> On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
>>>> Gary: So what is that goo on the right spring that's still in the unit
?
>>>> Roger Rucker
>>>> AA5A '78 HWO
>>>> -----Original Message-----
>>>> From: Gary L Vogt <teamgrumman@yahoo.com>
>>>> To: Teamgrumman List <teamgrumman-list@matronics.com>
>>>> Sent: Fri, Nov 1, 2013 12:13 am
>>>> Subject: TeamGrumman-List: MT Props
>>>>
>>>> I was going to post this on GG but realized I can't post pics.
>>>>
>>>> This is the second brush block installed on this plane. The first one f
ailed in less than 100 hours. This one failed in less than 90 hours.
>>>>
>>>> It isn't a well designed piece of hardware.
>>>>
>>>> Gary
>>>>
>>>>
>>>>
>>>> _blank">www.aeroelectric.com
>>>> .com" target="_blank">www.buildersbooks.com
>>>> ="_blank">www.homebuilthelp.com
>>>> ="_blank">www.mypilotstore.com
>>>> ank">www.mrrace.com
>>>> _blank">http://www.matronics.com/contribution
>>>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-Li
st
>>>> tp://forums.matronics.com
>>>
>>>
>>>
>>> =========
>>> ctric.com
>>> >www.buildersbooks.com
>>> uilthelp.com
>>> otstore.com
>>>
>>> matronics.com/contribution
>>> =========
>>> t">http://www.matronics.com/Navigator?TeamGrumman-List
>>> =========
>>> cs.com
>>> =========
>>
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> ="_blank">www.mypilotstore.com
>> ank">www.mrrace.com
>> _blank">http://www.matronics.com/contribution
>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List
>> tp://forums.matronics.com
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
Message 5
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Kevin:
Yes, I did misread your point. Looking back at it I doubt that there would
be two different parts for this operation. If the 12 V part was designed
properly handling the higher voltage and lower current for a 24 V part
would be easy. The 12 V system would be the worse case scenario, so 24 V
would be easy. In addition, nobody wants to carry double the inventory if
not needed.
Home made parts for this operation - I doubt it. You can read part numbers
on this brush block. We can't see elsewhere in the system though, Gary
will have to comment on that.
AND - I doubt if Gary would allow homemade parts.
*Barry*
*=93Chop=92d Liver=94*
NJ has taken the next step. They are identifying cars with bad drivers.
You will notice some cars with a large red "R" on them. That is to
identify the drivers as "R"estricted. Restricted is just a polite way of
saying Bad Drivers. Be cautious around them.
On Fri, Nov 1, 2013 at 11:13 AM, Airport Bum <aa5_driver@yahoo.com> wrote:
> Barry,
>
> I think you mis read my post. I stated...
>
> "Not knowing what year the tiger is, is it possible that the part is the
> wrong part number? Could that be the part for a 24 volt system and it is
> failing with double the amps at 12 volts?"
>
> And you replied...
>
> "But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect,
> you just have things reversed. If you INCREASE the Voltage (Double in th
is
> case) you DECREASE the Current (It would draw 1/2 the current in this
> case). Power (Watts) = I x E
> Lets say the system draws 200 Watts
>
> 200 Watts / 12 Volts = 16.66 Amps
>
> Now you up the voltage...
>
> 200 Watts / 24 Volts = 8.33 Amps"
>
>
> Yes, I know that 24 volts requires half the amps of 12 volts, or
> inversely, 12 volts takes twice the amps as 24 volts. That is why I aske
d
> if it was a 24 volt part being used in a 12 volt system that was causing
> the failure.
>
> No it's not my plane, but the prop interests me. I'd like to see the
> mount for the brushes as well as the harness. I'm wondering how much of
> this is factory parts vs how much is supplied/made by the installer?
>
>
> Any other ideas? Are any other mt users experiencing this issue?
>
> Kevin
>
> On Nov 1, 2013, at 9:00 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>
> Kevin:
>
> Is this your plane?
>
> I do not have enough pictures and I wish I could check the hardness of th
e
> material (Durometer) but yes, there are lots more questions that could co
me
> up:
> Question: Is this a dual brush system? Meaning two (2) brushes for each
> side of the connection. In a dual brush system the a single brush is
> usually chosen to handle 100% of the current Plus a safety margin of 50%
> more. In this case the individual size of the brush is too small. But
> therein lies the rub (Hamlet). You would go to a dual brush system becau
se
> of space and/or cost of a large brush. They did not have the space for a
> Large one brush system.
> There is also the idea of redundancy - If one brush should fail you would
> want to still have control over the prop.
>
> Ever notice in Motor Designs [look at a good quality electric drill] the
> Brush Runs Inside a METAL sleeve or Bakelite (not feasible in aircraft du
e
> to its brittleness) . This sleeve offers a lower coefficient of friction
> [Nylon and machined plastics; even Teflon have a very high coefficient of
> friction] for the sliding brush, an alternate current path, as well as
> cooling [heatsink] for the brushes. MT lost sight of the requirements.
>
> Getting back to your question Kevin:
> Yes, a bad ground or any bad connection in the MT system could cause high
> current.
>
> To answer a question before asked: Shouldn't the CARBON of the brush hel
p
> lower the coefficient of friction? YES, to some extent but the friction
> will wear away the carbon as well.
>
> But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect,
> you just have things reversed. If you INCREASE the Voltage (Double in th
is
> case) you DECREASE the Current (It would draw 1/2 the current in this
> case).
> Power (Watts) = I x E
> Lets say the system draws 200 Watts
> 200 Watts / 12 Volts = 16.66 Amps
> Now you up the voltage...
> 200 Watts / 24 Volts = 8.33 Amps
>
> I just had an appfinity - What if you installed an AMMETER in the circuit
.
> You should be able to monitor the condition of the brushes. As the
> brushes deteriorate the current would go up. Set a Delta for how much is
> acceptable and of course if a brush totally fails the current would jump.
>
> Gary - Being there is such a short life cycle [MTBF], this sure sounds
> like AD material and a phone call to MT is in order.
>
>
> *Barry*
> *=93Chop=92d Liver=94*
>
> NJ has taken the next step. They are identifying cars with bad drivers.
> You will notice some cars with a large red "R" on them. That is to
> identify the drivers as "R"estricted. Restricted is just a polite way of
> saying Bad Drivers. Be cautious around them.
>
>
> On Fri, Nov 1, 2013 at 7:04 AM, Airport Bum <aa5_driver@yahoo.com> wrote:
>
>> Barry,
>>
>> You may have shed some light on the issue. Not knowing what year the
>> tiger is, is it possible that the part is the wrong part number? Could
>> that be the part for a 24 volt system and it is failing with double the
>> amps at 12 volts? I don't recall this failure being discussed previousl
y
>> by any of those with the mt. Also wondering if there could be a ground
>> issue (bad ground) in the circuit somewhere causing resistance which is
>> causing a heat build up in this part?
>>
>> Kevin
>>
>> On Nov 1, 2013, at 3:49 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>>
>> Melted Block, Roger.
>>
>> MT chose the wrong material for the the insulation block. AND they did
>> not use a large enough brush system. One brush failed, guessing here,
>> probably by the copper braid loosing connection. This caused a high
>> resistance and a higher current through that brushes spring which, is no
t
>> copper - ergo still higher resistance , which caused the spring to heat
up
>> and melted the plastic.
>>
>>
>>
>> *Barry*
>> *=93Chop=92d Liver=94*
>>
>> NJ has taken the next step. They are identifying cars with bad drivers.
>> You will notice some cars with a large red "R" on them. That is to
>> identify the drivers as "R"estricted. Restricted is just a polite way o
f
>> saying Bad Drivers. Be cautious around them.
>>
>>
>> On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
>>
>>> Gary: So what is that goo on the right spring that's still in the
>>> unit?
>>> Roger Rucker
>>> AA5A '78 HWO
>>> -----Original Message-----
>>> From: Gary L Vogt <teamgrumman@yahoo.com>
>>> To: Teamgrumman List <teamgrumman-list@matronics.com>
>>> Sent: Fri, Nov 1, 2013 12:13 am
>>> Subject: TeamGrumman-List: MT Props
>>>
>>> I was going to post this on GG but realized I can't post pics.
>>>
>>> This is the second brush block installed on this plane. The first one
>>> failed in less than 100 hours. This one failed in less than 90 hours.
>>>
>>> It isn't a well designed piece of hardware.
>>>
>>> Gary
>>>
>>> *
>>>
>>> _blank">www.aeroelectric.com
>>> .com" target="_blank">www.buildersbooks.com
>>> ="_blank">www.homebuilthelp.com
>>> ="_blank">www.mypilotstore.com
>>> ank">www.mrrace.com
>>> _blank">http://www.matronics.com/contribution
>>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-Li
st
>>> tp://forums.matronics.com*
>>>
>>>
>> *
>>
>> =========
>> ctric.com
>> >www.buildersbooks.comuilthelp.comotstore.com
>> matronics.com/contribution
>>
>> =========
>> t">http://www.matronics.com/Navigator?TeamGrumman-List
>> ==========cs.com
>> ==========*
>>
>> *
>>
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> ="_blank">www.mypilotstore.com
>> ank">www.mrrace.com
>> _blank">http://www.matronics.com/contribution
>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-Lis
t
>> tp://forums.matronics.com
>> *
>>
>>
> *
>
> ========================
===========ctric.com
> >www.buildersbooks.comuilthelp.comotstore.com
> matronics.com/contribution
> ========================
> t">http://www.matronics.com/Navigator?TeamGrumman-List
> ========================
===========cs.com
> ========================
===========*
>
> *
>
===========
===========
===========
============*
>
>
Message 6
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I'm not claiming anyone used home made parts, just trying to determine how m
uch of the system is factory complete and, where, if any place can installer
error be injected. We're all human and make mistakes, heck I made one once
.....;).
I'd like to think your right about there being only one part, but still feel
the need to ask. I've not seen any install material from mt, so I don't kn
ow what they supply and what is required of the installer to complete the in
stall. There is some issue here, and apparently the cause is not readily as
certainable to Gary or the rest of us at this point. I'd be curious to kno
w what kind of resistance the circuit has. Without photos, documentation, o
r first hand knowledge, one has to ask questions to gain understanding.
Gary makes homemade parts all the time, and they are usually pretty good par
ts.
I'd still like to know if others are having this issue? What, if any, varia
bles exist from this install to others that may not have the same issue.
Kevin
On Nov 1, 2013, at 10:28 AM, FLYaDIVE <flyadive@gmail.com> wrote:
> Kevin:
>
> Yes, I did misread your point. Looking back at it I doubt that there woul
d be two different parts for this operation. If the 12 V part was designed p
roperly handling the higher voltage and lower current for a 24 V part would b
e easy. The 12 V system would be the worse case scenario, so 24 V would be e
asy. In addition, nobody wants to carry double the inventory if not needed.
>
> Home made parts for this operation - I doubt it. You can read part number
s on this brush block. We can't see elsewhere in the system though, Gary wi
ll have to comment on that.
> AND - I doubt if Gary would allow homemade parts.
>
>
>
> *Barry*
> *=9CChop=99d Liver=9D*
>
> NJ has taken the next step. They are identifying cars with bad drivers. Y
ou will notice some cars with a large red "R" on them. That is to identify
the drivers as "R"estricted. Restricted is just a polite way of saying Bad
Drivers. Be cautious around them.
>
>
> On Fri, Nov 1, 2013 at 11:13 AM, Airport Bum <aa5_driver@yahoo.com> wrote:
>> Barry,
>>
>> I think you mis read my post. I stated...
>>
>> "Not knowing what year the tiger is, is it possible that the part is the w
rong part number? Could that be the part for a 24 volt system and it is fai
ling with double the amps at 12 volts?"
>>
>> And you replied...
>>
>> "But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect,
you just have things reversed. If you INCREASE the Voltage (Double in this
case) you DECREASE the Current (It would draw 1/2 the current in this case)
. Power (Watts) = I x E
>> Lets say the system draws 200 Watts
>>>
>>> 200 Watts / 12 Volts = 16.66 Amps
>>> Now you up the voltage...
>>> 200 Watts / 24 Volts = 8.33 Amps"
>>
>> Yes, I know that 24 volts requires half the amps of 12 volts, or inversel
y, 12 volts takes twice the amps as 24 volts. That is why I asked if it was
a 24 volt part being used in a 12 volt system that was causing the failure.
>>
>> No it's not my plane, but the prop interests me. I'd like to see the mou
nt for the brushes as well as the harness. I'm wondering how much of this i
s factory parts vs how much is supplied/made by the installer?
>>
>>
>> Any other ideas? Are any other mt users experiencing this issue?
>>
>> Kevin
>>
>> On Nov 1, 2013, at 9:00 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>>
>>> Kevin:
>>>
>>> Is this your plane?
>>>
>>> I do not have enough pictures and I wish I could check the hardness of t
he material (Durometer) but yes, there are lots more questions that could co
me up:
>>> Question: Is this a dual brush system? Meaning two (2) brushes for eac
h side of the connection. In a dual brush system the a single brush is usua
lly chosen to handle 100% of the current Plus a safety margin of 50% more. I
n this case the individual size of the brush is too small. But therein lies
the rub (Hamlet). You would go to a dual brush system because of space and
/or cost of a large brush. They did not have the space for a Large one brus
h system.
>>> There is also the idea of redundancy - If one brush should fail you woul
d want to still have control over the prop.
>>>
>>> Ever notice in Motor Designs [look at a good quality electric drill] the
Brush Runs Inside a METAL sleeve or Bakelite (not feasible in aircraft due t
o its brittleness) . This sleeve offers a lower coefficient of friction [Ny
lon and machined plastics; even Teflon have a very high coefficient of frict
ion] for the sliding brush, an alternate current path, as well as cooling [h
eatsink] for the brushes. MT lost sight of the requirements.
>>>
>>> Getting back to your question Kevin:
>>> Yes, a bad ground or any bad connection in the MT system could cause hig
h current.
>>>
>>> To answer a question before asked: Shouldn't the CARBON of the brush he
lp lower the coefficient of friction? YES, to some extent but the friction w
ill wear away the carbon as well.
>>>
>>> But, your synopsis of a 24 Volt system Vs a 12 Volt System is incorrect,
you just have things reversed. If you INCREASE the Voltage (Double in this
case) you DECREASE the Current (It would draw 1/2 the current in this case)
.
>>> Power (Watts) = I x E
>>> Lets say the system draws 200 Watts
>>> 200 Watts / 12 Volts = 16.66 Amps
>>> Now you up the voltage...
>>> 200 Watts / 24 Volts = 8.33 Amps
>>>
>>> I just had an appfinity - What if you installed an AMMETER in the circui
t. You should be able to monitor the condition of the brushes. As the brus
hes deteriorate the current would go up. Set a Delta for how much is accept
able and of course if a brush totally fails the current would jump.
>>>
>>> Gary - Being there is such a short life cycle [MTBF], this sure sounds l
ike AD material and a phone call to MT is in order.
>>>
>>>
>>> *Barry*
>>> *=9CChop=99d Liver=9D*
>>>
>>> NJ has taken the next step. They are identifying cars with bad drivers.
You will notice some cars with a large red "R" on them. That is to ident
ify the drivers as "R"estricted. Restricted is just a polite way of saying B
ad Drivers. Be cautious around them.
>>>
>>>
>>> On Fri, Nov 1, 2013 at 7:04 AM, Airport Bum <aa5_driver@yahoo.com> wrote
:
>>>> Barry,
>>>>
>>>> You may have shed some light on the issue. Not knowing what year the t
iger is, is it possible that the part is the wrong part number? Could that b
e the part for a 24 volt system and it is failing with double the amps at 12
volts? I don't recall this failure being discussed previously by any of th
ose with the mt. Also wondering if there could be a ground issue (bad groun
d) in the circuit somewhere causing resistance which is causing a heat build
up in this part?
>>>>
>>>> Kevin
>>>>
>>>> On Nov 1, 2013, at 3:49 AM, FLYaDIVE <flyadive@gmail.com> wrote:
>>>>
>>>>> Melted Block, Roger.
>>>>>
>>>>> MT chose the wrong material for the the insulation block. AND they did
not use a large enough brush system. One brush failed, guessing here, prob
ably by the copper braid loosing connection. This caused a high resistance a
nd a higher current through that brushes spring which, is not copper - ergo s
till higher resistance , which caused the spring to heat up and melted the p
lastic.
>>>>>
>>>>>
>>>>>
>>>>> *Barry*
>>>>> *=9CChop=99d Liver=9D*
>>>>>
>>>>> NJ has taken the next step. They are identifying cars with bad driver
s. You will notice some cars with a large red "R" on them. That is to ide
ntify the drivers as "R"estricted. Restricted is just a polite way of sayin
g Bad Drivers. Be cautious around them.
>>>>>
>>>>>
>>>>> On Fri, Nov 1, 2013 at 12:46 AM, <n26390@aol.com> wrote:
>>>>>> Gary: So what is that goo on the right spring that's still in the un
it?
>>>>>> Roger Rucker
>>>>>> AA5A '78 HWO
>>>>>> -----Original Message-----
>>>>>> From: Gary L Vogt <teamgrumman@yahoo.com>
>>>>>> To: Teamgrumman List <teamgrumman-list@matronics.com>
>>>>>> Sent: Fri, Nov 1, 2013 12:13 am
>>>>>> Subject: TeamGrumman-List: MT Props
>>>>>>
>>>>>> I was going to post this on GG but realized I can't post pics.
>>>>>>
>>>>>> This is the second brush block installed on this plane. The first on
e failed in less than 100 hours. This one failed in less than 90 hours.
>>>>>>
>>>>>> It isn't a well designed piece of hardware.
>>>>>>
>>>>>> Gary
>>>>>>
>>>>>>
>>>>>>
>>>>>> _blank">www.aeroelectric.com
>>>>>> .com" target="_blank">www.buildersbooks.com
>>>>>> ="_blank">www.homebuilthelp.com
>>>>>> ="_blank">www.mypilotstore.com
>>>>>> ank">www.mrrace.com
>>>>>> _blank">http://www.matronics.com/contribution
>>>>>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-
List
>>>>>> tp://forums.matronics.com
>>>>>
>>>>>
>>>>>
>>>>> =========
>>>>> ctric.com
>>>>> >www.buildersbooks.com
>>>>> uilthelp.com
>>>>> otstore.com
>>>>>
>>>>> matronics.com/contribution
>>>>>
>>>>> =========
>>>>> t">http://www.matronics.com/Navigator?TeamGrumman-List
>>>>> =========
>>>>> cs.com
>>>>> =========
>>>>
>>>>
>>>> _blank">www.aeroelectric.com
>>>> .com" target="_blank">www.buildersbooks.com
>>>> ="_blank">www.homebuilthelp.com
>>>> ="_blank">www.mypilotstore.com
>>>> ank">www.mrrace.com
>>>> _blank">http://www.matronics.com/contribution
>>>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-Li
st
>>>> tp://forums.matronics.com
>>>
>>>
>>>
>>> =========
>>> ctric.com
>>> >www.buildersbooks.com
>>> uilthelp.com
>>> otstore.com
>>>
>>> matronics.com/contribution
>>> =========
>>> t">http://www.matronics.com/Navigator?TeamGrumman-List
>>> =========
>>> cs.com
>>> =========
>>
>>
>>
>> _blank">www.aeroelectric.com
>> .com" target="_blank">www.buildersbooks.com
>> ="_blank">www.homebuilthelp.com
>> ="_blank">www.mypilotstore.com
>> ank">www.mrrace.com
>> _blank">http://www.matronics.com/contribution
>> st" target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List
>> tp://forums.matronics.com
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
Message 7
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It melted=0A=0A=0A=0AOn Thursday, October 31, 2013 9:51 PM, "n26390@AOL.COM
" <n26390@AOL.COM> wrote:=0A =0AGary:- So what is that goo on the right s
pring that's still in the unit?=0ARoger Rucker =0AAA5A '78 HWO=0A-----Origi
nal Message-----=0AFrom: Gary L Vogt <teamgrumman@yahoo.com>=0ATo: Teamgrum
man List <teamgrumman-list@matronics.com>=0ASent: Fri, Nov 1, 2013 12:13 am
=0ASubject: TeamGrumman-List: MT Props=0A=0A=0AI was going to post this on
GG but realized I can't post pics.=0A=0AThis is the second brush block inst
alled on this plane. -The first one failed in less than 100 hours. -Thi
s one failed in less than 90 hours.=0A=0AIt isn't a well designed piece of
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