AeroElectric-List Digest Archive

Thu 02/13/14


Total Messages Posted: 11



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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    Time: 07:15:09 AM PST US
    From: Charlie England <ceengland7@gmail.com>
    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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    Time: 08:17:39 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    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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    Time: 08:38:41 AM PST US
    Subject: Re: Molex 638190100A crimper
    From: "jonlaury" <jonlaury@impulse.net>
    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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    Time: 08:39:14 AM PST US
    From: Charlie England <ceengland7@gmail.com>
    Subject: Re: engine pressure senders installation


    Message 5


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    Time: 09:00:29 AM PST US
    Subject: Re: engine pressure senders installation
    From: Robert Borger <rlborger@mac.com>
    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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    Time: 09:51:28 AM PST US
    Subject: Question about Z-19
    From: Hariharan Gopalan <rdu.hari@gmail.com>
    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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    Time: 10:32:18 AM PST US
    From: Charlie England <ceengland7@gmail.com>
    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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    Time: 10:57:29 AM PST US
    From: Charlie England <ceengland7@gmail.com>
    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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    Time: 12:10:23 PM PST US
    Subject: Re: Question about Z-19
    From: Hariharan Gopalan <rdu.hari@gmail.com>
    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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    Time: 12:54:59 PM PST US
    From: K <kleh@dialupatcost.ca>
    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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    Time: 05:41:25 PM PST US
    Subject: Re: engine pressure senders installation
    From: Robert Borger <rlborger@mac.com>
    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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