Today's Message Index:
----------------------
1. 07:15 AM - Re: engine pressure senders installation (Charlie England)
2. 08:17 AM - Re: engine pressure senders installation (Robert L. Nuckolls, III)
3. 08:38 AM - Re: Molex 638190100A crimper (jonlaury)
4. 08:39 AM - Re: engine pressure senders installation (Charlie England)
5. 09:00 AM - Re: engine pressure senders installation (Robert Borger)
6. 09:51 AM - Question about Z-19 (Hariharan Gopalan)
7. 10:32 AM - Re: Re: Molex 638190100A crimper (Charlie England)
8. 10:57 AM - Re: engine pressure senders installation (Charlie England)
9. 12:10 PM - Re: Question about Z-19 (Hariharan Gopalan)
10. 12:54 PM - Re: engine pressure senders installation (K)
11. 05:41 PM - Re: engine pressure senders installation (Robert Borger)
Message 1
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Subject: | Re: engine pressure senders installation |
I'm curious. How many pressure senders have broken *when directly
mounted to the engine*? I see a lot of reports of failures when there's
an extension, adapter, T fitting, etc, but there are thousands (hundreds
of thousands? millions?) of those sensors that live while directly
mounted on all types of automotive, industrial and a/c engines.
I might be wrong, but these are the questions I'd ask: How stiff is a
braided oil line when it's fully pressurized while the engine is
running? What does it weigh? How much vibration gets transmitted up the
fairly stiff pressurized line? How does that weight & vibration affect
the cantilevered *aluminum* adapters connecting it to the pressure
sensor? I suspect that the cantilevered weight of the hose is more than
the weight of the sensor, on its steel mounting threads, and there will
still be a lot of vibration transmitted to the fittings.
Am I mistaken?
Charlie
On 2/12/2014 11:58 PM, Matthew Prather wrote:
>
> Nice set of photos Bob.. I wonder if you also went back and provided strain
relief for the hose. I believe strain relief for the hose might be more important
than remote mounting the sender.
>
> Regards,
> Matt-
>
>> On Feb 6, 2014, at 11:45 AM, Robert Borger <rlborger@mac.com> wrote:
>>
>>
>> Carlos,
>>
>> You can see how I did it at: http://www.europaowners.org/main.php?g2_itemId=67636
>>
>> The first 11 pictures show how I did a remote mount of the oil pressure sender.
>>
>> Blue skies & tailwinds,
>> Bob Borger
>> Europa XS Tri, Rotax 914, Airmaster C/S Prop (50 hrs).
>> Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
>> 3705 Lynchburg Dr.
>> Corinth, TX 76208-5331
>> Cel: 817-992-1117
>> rlborger@mac.com
>>
>> On Feb 6, 2014, at 9:45 AM, Carlos Trigo <trigo@mail.telepac.pt> wrote:
>>
>>
>> Tim
>>
>> So, what is the way to mount engine pressure senders not cantilevered?
>>
>> Carlos
>>
Message 2
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Subject: | Re: engine pressure senders installation |
At 09:12 AM 2/13/2014, you wrote:
><ceengland7@gmail.com>
>
>I'm curious. How many pressure senders have broken *when directly
>mounted to the engine*? I see a lot of reports of failures when
>there's an extension, adapter, T fitting, etc, but there are
>thousands (hundreds of thousands? millions?) of those sensors that
>live while directly mounted on all types of automotive, industrial
>and a/c engines.
We need to sift the simple ideas that drive
levels of concern for this thread. (1) non-ferrous
plumbing/attache hardware that has a finite
service life subjected to the as-installed,
vibration stress levels and (2) lever moments
which are product of mass x arm that produces
the leverage under vibratory acceleration.
There's nothing inherently risky about mounting
a sensor right to the engine. It's done on cars
all the time . . . and probably less vibration
stress. Consider this oil pressure transducer.
Emacs!
All steel structure, short moment arm, light
mass . . . risk approaching zero.
Consider this one . . .
Emacs!
Hmmm . . . fatter, longer, but still steel . . .
probably still okay plugged right into the engine.
But consider the installation that demands
multiple 'sensors' . . . say one of these
fat rascals, stuck into a brass tee-fitting opposite
a low oil pressure warning switch. Now put
a not-so-close brass nipple. The high risk
joint is where the brass screws into the
engine with all that stuff hung off the
end.
There's are ancillary concerns for deciding
whether or not to mount a sensor directly
to the engine . . . temperature and vibration
effects on the transducer itself . . .generally
low risk but a question to ask and answer.
>I might be wrong, but these are the questions I'd ask: How stiff is
>a braided oil line when it's fully pressurized while the engine is
>running? What does it weigh? How much vibration gets transmitted up
>the fairly stiff pressurized line? How does that weight & vibration
>affect the cantilevered *aluminum* adapters connecting it to the
>pressure sensor? I suspect that the cantilevered weight of the hose
>is more than the weight of the sensor, on its steel mounting
>threads, and there will still be a lot of vibration transmitted to
>the fittings.
>
>Am I mistaken?
Stresses that a flexible line would put on
the threads at the engine are minimal . . . if
the threads are steel . . . the risks are zero.
Risks risk sharply with high moment installations
on rigid, brass, pot-metal or aluminum, christmas-trees.
Bob . . .
Message 3
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Subject: | Re: Molex 638190100A crimper |
Hi Bob,
The pins are tiny little buggers (photo) : Molex MicroBlade 50011 Series Crimp
pins Part# 50011-8000
John
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=418658#418658
Attachments:
http://forums.matronics.com//files/silver_machine4_005_large_208.jpg
Message 4
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Subject: | Re: engine pressure senders installation |
Message 5
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Subject: | Re: engine pressure senders installation |
Hi Charlie,
My original concern for having the oil pressure sender mounted on the engine was
a result of a series short time of oil pressure sender failures which were reported
on the Rotax and Europa lists a number of years ago. Due to the placement
of the sender on the engine it was surmised that these were failures from
the sender being repeatedly shaken during engine start and stop. The recommendation
was made by someone on the list that the sender be removed from the engine
and remote mounted on the firewall to get it out of the vibrational environment
of the engine.
In my case I used a length of Aeroquip 666 1/8 hose which is braided stainless
steel over teflon with stainless steel fittings. I have never weighed the line
but it isnt very heavy. Just went out to the shop and weighed a similar length
of 666 with fittings and it weighs 2 oz. I doubt it is any stiffer pressurized
than it is unpressurized. There are no aluminum fittings connecting to
the engine. A steel AN fitting was used to connect the hose to the engine. The
weight of the hose as supported by the engine fitting is considerably less
than the weight of the sender ~16 oz. Considerably less than an ounce on the
fitting. I have confirmed that there are no vibrations being transmitted through
the hose back to the sender or its fittings. The hose seems to do a good
job of absorbing rather than transmitting vibrations.
Hope this helps.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop (50 hrs).
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
rlborger@mac.com
On Feb 13, 2014, at 9:12 AM, Charlie England <ceengland7@gmail.com> wrote:
I'm curious. How many pressure senders have broken *when directly mounted to the
engine*? I see a lot of reports of failures when there's an extension, adapter,
T fitting, etc, but there are thousands (hundreds of thousands? millions?)
of those sensors that live while directly mounted on all types of automotive,
industrial and a/c engines.
I might be wrong, but these are the questions I'd ask: How stiff is a braided oil
line when it's fully pressurized while the engine is running? What does it
weigh? How much vibration gets transmitted up the fairly stiff pressurized line?
How does that weight & vibration affect the cantilevered *aluminum* adapters
connecting it to the pressure sensor? I suspect that the cantilevered weight
of the hose is more than the weight of the sensor, on its steel mounting threads,
and there will still be a lot of vibration transmitted to the fittings.
Am I mistaken?
Charlie
Message 6
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Subject: | Question about Z-19 |
Hello Bob
I salute your passion and am in awe and amazement at the collection of
information and knowledge that you have shared.
Z-19 mentions about different notes in several places, after spending
several hours looking through all the documents and the book, somehow I am
unable to locate these notes. Could you please help with this?
Thanks
Hari
Message 7
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Subject: | Re: Molex 638190100A crimper |
http://www.walmart.com/ip/30-Watt-Soldering-Iron/16539504
;-)
On 2/13/2014 10:35 AM, jonlaury wrote:
>
> Hi Bob,
>
> The pins are tiny little buggers (photo) : Molex MicroBlade 50011 Series Crimp
pins Part# 50011-8000
>
> John
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=418658#418658
>
>
> Attachments:
>
> http://forums.matronics.com//files/silver_machine4_005_large_208.jpg
>
>
Message 8
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Subject: | Re: engine pressure senders installation |
Hi Bob,
I do understand worrying about stress & vibration issues. What caught my
attention was what appeared to be aluminum adapters on the pressure
sensor itself, cantilevering the right angle adapter and hose away from
the sensor's mount. I could imagine the aluminum adapters being at risk
more than the steel threaded sensor.
What was the nature of the failures? I was envisioning the sender
breaking off at the threads. Was it some sort of internal failure,
instead? Most current RV-x builders do remote mount the sensor, but they
seem to survive on a lot of motors when they are direct- mounted. If
there is a high percentage of failures on the Rotax, I wonder if it's
caused by the very different frequency of vibration from the Rotax,
compared to most other engines running at constant-RPM.
Charlie
On 2/13/2014 10:57 AM, Robert Borger wrote:
>
> Hi Charlie,
>
> My original concern for having the oil pressure sender mounted on the engine
was a result of a series short time of oil pressure sender failures which were
reported on the Rotax and Europa lists a number of years ago. Due to the placement
of the sender on the engine it was surmised that these were failures from
the sender being repeatedly shaken during engine start and stop. The recommendation
was made by someone on the list that the sender be removed from the
engine and remote mounted on the firewall to get it out of the vibrational environment
of the engine.
>
> In my case I used a length of Aeroquip 666 1/8 hose which is braided stainless
steel over teflon with stainless steel fittings. I have never weighed the line
but it isnt very heavy. Just went out to the shop and weighed a similar length
of 666 with fittings and it weighs 2 oz. I doubt it is any stiffer pressurized
than it is unpressurized. There are no aluminum fittings connecting to
the engine. A steel AN fitting was used to connect the hose to the engine.
The weight of the hose as supported by the engine fitting is considerably less
than the weight of the sender ~16 oz. Considerably less than an ounce on the
fitting. I have confirmed that there are no vibrations being transmitted through
the hose back to the sender or its fittings. The hose seems to do a good
job of absorbing rather than transmitting vibrations.
>
> Hope this helps.
>
> Blue skies & tailwinds,
> Bob Borger
> Europa XS Tri, Rotax 914, Airmaster C/S Prop (50 hrs).
> Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
> 3705 Lynchburg Dr.
> Corinth, TX 76208-5331
> Cel: 817-992-1117
> rlborger@mac.com
>
> On Feb 13, 2014, at 9:12 AM, Charlie England <ceengland7@gmail.com> wrote:
>
>
> I'm curious. How many pressure senders have broken *when directly mounted to
the engine*? I see a lot of reports of failures when there's an extension, adapter,
T fitting, etc, but there are thousands (hundreds of thousands? millions?)
of those sensors that live while directly mounted on all types of automotive,
industrial and a/c engines.
>
> I might be wrong, but these are the questions I'd ask: How stiff is a braided
oil line when it's fully pressurized while the engine is running? What does it
weigh? How much vibration gets transmitted up the fairly stiff pressurized line?
How does that weight & vibration affect the cantilevered *aluminum* adapters
connecting it to the pressure sensor? I suspect that the cantilevered weight
of the hose is more than the weight of the sensor, on its steel mounting threads,
and there will still be a lot of vibration transmitted to the fittings.
>
> Am I mistaken?
>
> Charlie
>
Message 9
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Subject: | Re: Question about Z-19 |
Please ignore my request for details on the notes, I did find it in the
book.
Thanks
Hari
On Thu, Feb 13, 2014 at 12:49 PM, Hariharan Gopalan <rdu.hari@gmail.com>wrote:
> Hello Bob
>
> I salute your passion and am in awe and amazement at the collection of
> information and knowledge that you have shared.
>
> Z-19 mentions about different notes in several places, after spending
> several hours looking through all the documents and the book, somehow I am
> unable to locate these notes. Could you please help with this?
>
> Thanks
> Hari
>
Message 10
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Subject: | Re: engine pressure senders installation |
Years ago while touring a rotax overhaul facility I noticed the vdo
electro-mechanical pressure senders had a significant added weight
attached to them. The story was that this was to lower the resonant
frequency below what the engine would excite to prevent them from
breaking off. Those engines run at twice the rpm that a Lycoming runs at.
ken
do not archive
> If
> there is a high percentage of failures on the Rotax, I wonder if it's
> caused by the very different frequency of vibration from the Rotax,
> compared to most other engines running at constant-RPM.
>
> Charlie
>
Message 11
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Subject: | Re: engine pressure senders installation |
Charlie,
Yes, there are Al fittings on the sender in the pictures. They were
only for test fitting purposes. Matter of fact, the installation ended
up quite different from the build pictures. I ended up using a longer
length of 666 which was routed over the engine to the sensor. It was
covered in firesleeve & heat shield and tied off a couple times along
the way. I also used steel fittings on the sensor. The aircraft is
down for some repair work and Annual Condition Inspection so I was able
to take some pictures today.
Vibration transmitted to the sensor is pretty close to zero.
The oil pressure senders died from internal failures. The either
stopped sending or sent invalid readings. There were no physical
failures of the attachment to the engine. Those only seemed to occur
when additional fittings were installed between the sender and oil pump.
As was pointed out in another e-mail, a brass weight ring was added to
the sender to modify the harmonic frequency and reduce vibration issues.
I don=92t know if this was effective or not. Haven=92t seen any
complaints of oil pressure sender failures for a couple year.
Yes, there are much different vibration issues with the Rotax. Cruise
RPM in a 91X is 5000 to 5500 RPM. There=92s a 2.43:1 gearbox to the
prop so it is turning at .41 of the engine speed. All these things make
for a challenging vibrational environment.
I=92m presently building a Little Toot Sport Biplane and I will probably
direct mount the oil pressure sender to the engine as it is a Lycoming
IO-320.
Blue skies & tailwinds,
Bob Borger
Europa XS Tri, Rotax 914, Airmaster C/S Prop (50 hrs).
Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
3705 Lynchburg Dr.
Corinth, TX 76208-5331
Cel: 817-992-1117
rlborger@mac.com
On Feb 13, 2014, at 12:56 PM, Charlie England <ceengland7@gmail.com>
wrote:
<ceengland7@gmail.com>
Hi Bob,
I do understand worrying about stress & vibration issues. What caught my
attention was what appeared to be aluminum adapters on the pressure
sensor itself, cantilevering the right angle adapter and hose away from
the sensor's mount. I could imagine the aluminum adapters being at risk
more than the steel threaded sensor.
What was the nature of the failures? I was envisioning the sender
breaking off at the threads. Was it some sort of internal failure,
instead? Most current RV-x builders do remote mount the sensor, but they
seem to survive on a lot of motors when they are direct- mounted. If
there is a high percentage of failures on the Rotax, I wonder if it's
caused by the very different frequency of vibration from the Rotax,
compared to most other engines running at constant-RPM.
Charlie
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