---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 04/20/10: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:40 AM - Re: Facet pumps: Energy vs. Flow (Bill Boyd) 2. 05:43 AM - Re: Facet pumps: Energy vs. Flow (rampil) 3. 05:48 AM - Re: Facet pumps: Energy vs. Flow (BobsV35B@aol.com) 4. 06:09 AM - Re: Re: Facet pumps: Energy vs. Flow (Jon Finley) 5. 07:51 AM - Re: (BobsV35B@aol.com) 6. 07:58 AM - Re: Re: Facet pumps: Energy vs. Flow (BobsV35B@aol.com) 7. 10:35 AM - Re: Facet pumps: Energy vs. Flow (Mike Welch) 8. 11:05 AM - Re: Re: Facet pumps: Energy vs. Flow (BobsV35B@aol.com) 9. 01:53 PM - Re: switch breaker on ALT field (rckol) 10. 03:38 PM - S704-1 on Hot Side of Firewall? (Noah) 11. 08:30 PM - Re: S704-1 on Hot Side of Firewall? (Robert L. Nuckolls, III) 12. 08:36 PM - Re: Re: switch breaker on ALT field (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 04:40:20 AM PST US Subject: Re: AeroElectric-List: Facet pumps: Energy vs. Flow From: Bill Boyd How about some filtering on the "input" line of the ammeter? If we're looking at constant-amplitude square wave current pulses of varying frequency, a capacitive filter to perform an "integral" function might give you an average-current-over-time measurement that closely matches the frequency and therefore the load on the pump. In practice, I am not sure from listening to my Facet pump all these years how much the frequency changes as a function of load. There is a sound change as it self-primes when I first hit it before engine-start. Just a thought. I had to do the pneumatic equivalent (expansion chamber plus input restrictor) to keep my manifold pressure digital readout from jumping all around in an un-readable fashion. A little RC pi or L network might do what you need. Bill B. On Mon, Apr 19, 2010 at 9:56 PM, Charlie England wrote: > ceengland@bellsouth.net> > > Certificated. Bummer. > > If you think you can legally use current sensing, have you tried a > restricter in the pump's output to see if it will raise the current enough > to be measurable vs the no-flow state? > > On 4/19/2010 6:16 PM, BobsV35B@aol.com wrote: > >> Good Morning Charlie, >> Those units by Pillar Point Electronics look very promising. As I said a >> couple of messages back, I need something that can be used on a normally >> certificated aircraft. Not sure about the PPE product, but I am checking >> into it. >> Thanks for the comment. >> Happy Skies, >> Old Bob >> In a message dated 4/19/2010 4:50:49 P.M. Central Daylight Time, >> ceengland@bellsouth.net writes: >> >> >> >> On 4/19/2010 3:03 PM, ROGER & JEAN CURTIS wrote: >> > >> > To me, they look and sound just like the ones that were used >> > on those Ford gasoline fired heaters back in the thirties. But >> my memory >> > could be fooling me. >> > >> > Those were probably the Stewart Warner or Bendix pumps. >> > Whadda Ya Think? >> > >> > If so. does that mean I need to monitor the frequency some >> > how? >> > >> > This is getting complicated,. No wonder nobody does it! >> > >> > Happy Skies, >> > >> > Old Bob >> > >> > I am not sure of the application here, but I >> > believe that there should be a significant pressure drop on the >> output of >> > the pump, when there is no longer any fuel. This being the >> case, perhaps >> > you could use a pressure switch, similar to what is used to >> monitor engine >> > oil pressure and turn on the hobbs meter, on some aircraft. You >> would need >> > to check the pressure differential between pumping fuel and >> empty tank >> > pumping, and use a switch midway between. This would be a >> normally closed >> > switch which would open when there is fuel flow and close, to >> turn on the >> > light when there is no more fuel to pump. >> > >> > Not sure if this is a viable option for your >> > application, but might work, and is very simple. (I especially like >> > simple:-) >> > >> > Roger >> > >> If you're using it as a transfer pump, there won't be a lot of >> pressure >> since it will be just the 'head' from one tank to the other. Often no >> more than a few inches of rise, plus the resistance of the tubing. >> >> How about one of the sensing devices using light to detect the >> presence >> of liquid? I bought a couple several years ago, intending to use >> them to >> monitor end-of-transfer from my aux tanks, then forgot to install >> them.... They mount in a single hole & have a cone shaped plexi >> tip. An >> LED shines out through the plexi; presence/absence of liquid >> changes the >> light reflected back into the photocell in the same housing, changing >> the state of the sense line. >> >> If that interests you, I'll try to locate the name of the device & a >> source for you. >> >> Charlie >> >> * >> >> >> * >> > > ________________________________ Message 2 _____________________________________ Time: 05:43:01 AM PST US Subject: AeroElectric-List: Re: Facet pumps: Energy vs. Flow From: "rampil" Good engineering principles favor measuring the actual parameter you want, rather than a surrogate, especially when there is no reliable one-to-one mapping of one to the other. In the case of current draw, for example, overheating the coil or dirt in the mechanism will probably change the current draw Pressure downstream would depend on where the fill hose enters the downstream tank, if at the bottom, or at a positive hydrostatic head, the pressure downstream of the pump will stay positive while there is fuel in the tank. What about measuring fuel level in the feeding tank, is not that what you really want to make a decision with? When it reads zero, stop pumping? -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=294942#294942 ________________________________ Message 3 _____________________________________ Time: 05:48:55 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Facet pumps: Energy vs. Flow Good Morning Bill, Wow! It appears that any suitable current measuring device will be a lot more complex than my feeble brain can comprehend. Thanks to you and all the others that have contributed to my on going education. In any case, it does seem that a few breadboard experiments are in order. Happy Skies, Old Bob In a message dated 4/20/2010 6:41:53 A.M. Central Daylight Time, sportav8r@gmail.com writes: How about some filtering on the "input" line of the ammeter? If we're looking at constant-amplitude square wave current pulses of varying frequency, a capacitive filter to perform an "integral" function might give you an average-current-over-time measurement that closely matches the frequency and therefore the load on the pump. In practice, I am not sure from listening to my Facet pump all these years how much the frequency changes as a function of load. There is a sound change as it self-primes when I first hit it before engine-start. Just a thought. I had to do the pneumatic equivalent (expansion chamber plus input restrictor) to keep my manifold pressure digital readout from jumping all around in an un-readable fashion. A little RC pi or L network might do what you need. Bill B. On Mon, Apr 19, 2010 at 9:56 PM, Charlie England <_ceengland@bellsouth.net_ (mailto:ceengland@bellsouth.net) > wrote: <_ceengland@bellsouth.net_ (mailto:ceengland@bellsouth.net) > Certificated. Bummer. If you think you can legally use current sensing, have you tried a restricter in the pump's output to see if it will raise the current enough to be measurable vs the no-flow state? On 4/19/2010 6:16 PM, _BobsV35B@aol.com_ (mailto:BobsV35B@aol.com) wrote: Good Morning Charlie, Those units by Pillar Point Electronics look very promising. As I said a couple of messages back, I need something that can be used on a normally certificated aircraft. Not sure about the PPE product, but I am checking into it. Thanks for the comment. Happy Skies, Old Bob In a message dated 4/19/2010 4:50:49 P.M. Central Daylight Time, _ceengland@bellsouth.net_ (mailto:ceengland@bellsouth.net) writes: <_ceengland@bellsouth.net_ (mailto:ceengland@bellsouth.net) > On 4/19/2010 3:03 PM, ROGER & JEAN CURTIS wrote: > > To me, they look and sound just like the ones that were used > on those Ford gasoline fired heaters back in the thirties. But my memory > could be fooling me. > > Those were probably the Stewart Warner or Bendix pumps. > Whadda Ya Think? > > If so. does that mean I need to monitor the frequency some > how? > > This is getting complicated,. No wonder nobody does it! > > Happy Skies, > > Old Bob > > I am not sure of the application here, but I > believe that there should be a significant pressure drop on the output of > the pump, when there is no longer any fuel. This being the case, perhaps > you could use a pressure switch, similar to what is used to monitor engine > oil pressure and turn on the hobbs meter, on some aircraft. You would need > to check the pressure differential between pumping fuel and empty tank > pumping, and use a switch midway between. This would be a normally closed > switch which would open when there is fuel flow and close, to turn on the > light when there is no more fuel to pump. > > Not sure if this is a viable option for your > application, but might work, and is very simple. (I especially like > simple:-) > > Roger > If you're using it as a transfer pump, there won't be a lot of pressure since it will be just the 'head' from one tank to the other. Often no more than a few inches of rise, plus the resistance of the tubing. How about one of the sensing devices using light to detect the presence of liquid? I bought a couple several years ago, intending to use them to monitor end-of-transfer from my aux tanks, then forgot to install them.... They mount in a single hole & have a cone shaped plexi tip. An LED shines out through the plexi; presence/absence of liquid changes the light reflected back into the photocell in the same housing, changing the state of the sense line. If that interests you, I'll try to locate the name of the device & a source for you. Charlie ________________________________ Message 4 _____________________________________ Time: 06:09:04 AM PST US Subject: RE: AeroElectric-List: Re: Facet pumps: Energy vs. Flow From: "Jon Finley" =0AI find this discussion very interesting and hope for an inexpensive solu tion. I really like that Pillar Point flow detector but the price is more than I'd like to spend.=0A =0AJust to add some data points.... In my case, I know the fuel level in the tank but I wish to know when fuel stops being delivered to that tank so alternate plans can be made. So, a "fuel is not f lowing" indicator would add a level of comfort (would be "nice" but certain ly not mandatory since I am currently flying without this).=0A =0AMore spec ifically, I have a large main tank from which fuel is pumped into the heade r. The header is about 5 gallons (one hour of flight time). I typically l eave my transfer pump on all the time. If it were to stop and I didn't not ice (which is likely), I have a warning light that will come on at about 2. 5-3 gallons. That leaves me with about 30 minutes to figure out what to do . If I had known immediately, I would have had 60 minutes. Of course, I h ave a backup fuel pump which I would immediately switch on. However; it ca n take some time before seeing the fuel level start to rise. When dealing w ith a 30 minute window, knowing now versus knowing in 5-10 minutes is a big deal (at least in terms of my stress level - FYI, I live out west were air ports are frequently more than 30 minutes apart).=0A=0AJon Finley=0AN314JF - Q2 - Subaru EJ22=0A[http://www.finleyweb.net/Q2Subaru.aspx] http://www.fi nleyweb.net/Q2Subaru.aspx=0A =0A =0A=0A-----Original Message-----=0AFrom: " rampil" =0ASent: Tuesday, April 20, 2010 6:41am=0ATo: aeroelectric-list@matronics.com=0ASubject: AeroElectric-List: Re: Facet pu =0A=0AGood engineering principles favor measuring th e actual parameter=0Ayou want, rather than a surrogate, especially when the re is no=0Areliable one-to-one mapping of one to the other.=0A=0AIn the cas e of current draw, for example, overheating the coil or dirt=0Ain the mecha nism will probably change the current draw=0APressure downstream would depe nd on where the fill hose enters the =0Adownstream tank, if at the bottom, or at a positive hydrostatic head, the =0Apressure downstream of the pump w ill stay positive while there is fuel=0Ain the tank.=0A=0AWhat about measur ing fuel level in the feeding tank, is not that what you=0Areally want to m ake a decision with? When it reads zero, stop pumping?=0A=0A--------=0AIra N224XS=0A=0A=0A=0A=0ARead this topic online here:=0A=0Ahttp://forums.matron ================0A=0A=0A=0A ________________________________ Message 5 _____________________________________ Time: 07:51:11 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Test --- Do Not Archive In a message dated ________________________________ Message 6 _____________________________________ Time: 07:58:18 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Re: Facet pumps: Energy vs. Flow Good Morning Ira, I have what I consider to be relatively good fuel gauges in the tanks, but find that there is at least a ten to fifteen minute window between where the gauge says empty and it actually will be dry. I do not wish to turn the pump off too soon and have fuel in the tank that has not been used and I do not like to run the pump when it is not actually pumping fuel. It would be very nice to be able to verify the accuracy of the fuel gauge by noting when the pump stops pumping fuel rather than running the pump while dry for possibly an extra ten to fifteen minutes every time I utilize the auxiliary fuel tank. I do have excellent fuel use measuring capability and what I do now is note the fuel burned number when I turn on the pump and shut it off when the amount of fuel known to be in the tank has been burned. Nevertheless, it would be nice to know within seconds when the tank has run dry so that the pump could be turned off. I really would rather not be running the pump when it is not pumping fuel. Happy Skies, Old Bob In a message dated 4/20/2010 7:43:50 A.M. Central Daylight Time, ira.rampil@gmail.com writes: --> AeroElectric-List message posted by: "rampil" Good engineering principles favor measuring the actual parameter you want, rather than a surrogate, especially when there is no reliable one-to-one mapping of one to the other. In the case of current draw, for example, overheating the coil or dirt in the mechanism will probably change the current draw Pressure downstream would depend on where the fill hose enters the downstream tank, if at the bottom, or at a positive hydrostatic head, the pressure downstream of the pump will stay positive while there is fuel in the tank. What about measuring fuel level in the feeding tank, is not that what you really want to make a decision with? When it reads zero, stop pumping? -------- Ira N224XS ________________________________ Message 7 _____________________________________ Time: 10:35:34 AM PST US From: Mike Welch Subject: AeroElectric-List: Re: Facet pumps: Energy vs. Flow Bob=2C Pardon me for butting in=2C but from my experience with certificated airp lanes=2C it is virtually impossible to get a field approval like you're aft er. I used to have a 1961 Cessna 172=2C with an O-300 Continental. On those hot mid-summer California days (100+)=2C my oil temps got well into the red on climbout!! I checked the accuracy of the gauge=2C and it was correct! Therefore=2C I wanted to add an oil cooler to my Cessna 172. It didn't c ome with one=2C but I could get a later model 172 oil cooler to fit. I sen t off my Form 337 to the local FSDO=2C and their first reaction was "NO!" Their attitude was "if it didn't come with one=2C it doesn't need one!!" I was irritated (to say the least)=2C and requested an appeal. They fina lly relented and said it would be okay. For crying out loud =2C it was jus t an oil cooler!! (all certified parts=2C too) My opinion is=3B there ain't no way you can legally add any kind of perma nent parts to modify to your fuel pump=2C fuel lines=2C or anything else=2C on a certificated airplane=2C without that approved 337. Just my opinion................. Mike Welch From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Re: Facet pumps: Energy vs. Flow Good Morning Ira=2C I have what I consider to be relatively good fuel gauges in the tanks=2C bu t find that there is at least a ten to fifteen minute window between where the gauge says empty and it actually will be dry. I do not wish to turn the pump off too soon and have fuel in the tank that has not been used and I d o not like to run the pump when it is not actually pumping fuel. It would be very nice to be able to verify the accuracy of the fuel gauge b y noting when the pump stops pumping fuel rather than running the pump whil e dry for possibly an extra ten to fifteen minutes every time I utilize the auxiliary fuel tank. I do have excellent fuel use measuring capability and what I do now is note the fuel burned number when I turn on the pump and shut it off when the am ount of fuel known to be in the tank has been burned. Nevertheless=2C it would be nice to know within seconds when the tank has r un dry so that the pump could be turned off. I really would rather not be running the pump when it is not pumping fuel. Happy Skies=2C Old Bob In a message dated 4/20/2010 7:43:50 A.M. Central Daylight Time=2C ira.ramp il@gmail.com writes: Good engineering principles favor measuring the actual parameter you want=2C rather than a surrogate=2C especially when there is no reliable one-to-one mapping of one to the other. In the case of current draw=2C for example=2C overheating the coil or dirt in the mechanism will probably change the current draw Pressure downstream would depend on where the fill hose enters the downstream tank=2C if at the bottom=2C or at a positive hydrostatic head=2C the pressure downstream of the pump will stay positive while there is fuel in the tank. What about measuring fuel level in the feeding tank=2C is not that what you really want to make a decision with? When it reads zero=2C stop pumping? -------- Ira N224XS _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:O N:WL:en-US:WM_HMP:042010_2 ________________________________ Message 8 _____________________________________ Time: 11:05:32 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Re: Facet pumps: Energy vs. Flow Good Afternoon Mike, Believe it or not I do understand your frustration and the problems that are faced when dealing with the FAA. It is my opinion that the vast majority of the folks at FAA want to do a good job, but are so hamstrung with regulations and paper work that it is easier to just say no. However, I have had fairly good luck getting local approvals from my supervising FSDO. As I think we can all agree, each FSDO is a kingdom unto itself and what is easy to get approved at one office may be impossible at another. Nevertheless, I have gotten several local approvals here locally. I do hold an A&P with Inspection Authorization. It does help me know who I should present the data to and how the presentation should be made. In general, if we can think of a way to add something that has no chance of interfering with required equipment, the local approval has a better chance of being approved. Once again, the FAA has no obligation to ever issue a local approval. In fact, if an individual inspector does issue the approval, he is doing it on his own knowledge and is personally responsible for what happens. In many ways it is surprising that any FAA inspector ever issues a local approval. He/she has no obligation to do so. It is just a privilege he has been accorded. Failure to do so does not hurt his career at all, but making a dumb approval could end his career. Happy Skies, Old Bob In a message dated 4/20/2010 12:37:05 P.M. Central Daylight Time, mdnanwelch7@hotmail.com writes: Bob, Pardon me for butting in, but from my experience with certificated airplanes, it is virtually impossible to get a field approval like you're after. I used to have a 1961 Cessna 172, with an O-300 Continental. On those hot mid-summer California days (100+), my oil temps got well into the red on climbout!! I checked the accuracy of the gauge, and it was correct! Therefore, I wanted to add an oil cooler to my Cessna 172. It didn't come with one, but I could get a later model 172 oil cooler to fit. I sent off my Form 337 to the local FSDO, and their first reaction was "NO!" Their attitude was "if it didn't come with one, it doesn't need one!!" I was irritated (to say the least), and requested an appeal. They finally relented and said it would be okay. For crying out loud , it was just an oil cooler!! (all certified parts, too) My opinion is; there ain't no way you can legally add any kind of permanent parts to modify to your fuel pump, fuel lines, or anything else, on a certificated airplane, without that approved 337. Just my opinion................. Mike Welch ________________________________ Message 9 _____________________________________ Time: 01:53:26 PM PST US Subject: AeroElectric-List: Re: switch breaker on ALT field From: "rckol" Switch breakers will function for this application. I have read conflicting reports about the long term reliability of these. Some folks end up tearing them out because they don't hold up and others have no trouble with them. Sorry, I don't have any brand specific recommendations. I am not going to use them. Dick -------- rck Read this topic online here: http://forums.matronics.com/viewtopic.php?p=295024#295024 ________________________________ Message 10 ____________________________________ Time: 03:38:33 PM PST US Subject: AeroElectric-List: S704-1 on Hot Side of Firewall? From: "Noah" I requested the spec sheet for the S704-1 relay from B&C, and it is a Tyco T9A with an operating temp limit of 85C (185F). This seems a bit low for mounting in the engine compartment on the firewall. where I had been planning to mount it. I called B&C to ask them if they recommended mounting these in the engine compartment and the gentleman I spoke with was not sure - he recommended a post here. Anybody know what the firewall temps can climb to?? Anybody mounted one of these firewall forward in an RV and had problems? Or had it last 2000 hours without issue?? -------- Highest Regards, Noah Forden RV-7A Rhode Island Read this topic online here: http://forums.matronics.com/viewtopic.php?p=295030#295030 ________________________________ Message 11 ____________________________________ Time: 08:30:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: S704-1 on Hot Side of Firewall? At 05:36 PM 4/20/2010, you wrote: > >I requested the spec sheet for the S704-1 relay from B&C, and it is >a Tyco T9A with an operating temp limit of 85C (185F). This seems a >bit low for mounting in the engine compartment on the firewall. >where I had been planning to mount it. I called B&C to ask them if >they recommended mounting these in the engine compartment and the >gentleman I spoke with was not sure - he recommended a post here. > >Anybody know what the firewall temps can climb to?? Anybody mounted >one of these firewall forward in an RV and had problems? Or had it >last 2000 hours without issue?? It will be fine. These devices and their close cousins are used under the hood of motor vehicles and they're fine. The various companies I've worked for have done numerous studies of temperature under the cowl and found that nothing gets really all that hot as long as it's not exposed to direct infra-red radiation from stacks (particularly turbochargers). I've seen some RG battery cases melted because they were too close to exhaust pipes. Bob . . . ________________________________ Message 12 ____________________________________ Time: 08:36:06 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: switch breaker on ALT field At 03:50 PM 4/20/2010, you wrote: > >Switch breakers will function for this application. > >I have read conflicting reports about the long term reliability of >these. Some folks end up tearing them out because they don't hold >up and others have no trouble with them. Sorry, I don't have any >brand specific recommendations. I am not going to use them. The mil-qualified sw/breakers are fine. Actually, the P&B W31 series are reasonably decent too. There's about 80K in service in Bonanzas and Barons since way back when . . . and yes, a few have failed in a way that put smoke in the cockpit . . . but those were the 30A devices that control electric prop de-ice. Obviously, you can't get the features in single switches of any kind that are offered in the progressive- transfer 2-pole toggles (2-10, 2-50, 2-70) but if your design goals don't require this feature, then the single switches will do. Now, having said that, I'm not sure I'd recommend the W31 used upstream of a crowbar ov protection system that I designed. I've not studied the trip dynamics of this device in that application. The miniature TI/Klixon style breakers have been paired with our crowbar ov systems by the thousands with good service histories. 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