---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 02/09/19: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:40 AM - Arplast PV50 Propeller Motor (BobD) 2. 03:05 AM - Re: Arplast PV50 Propeller Motor (Jan de Jong) 3. 05:15 AM - Re: Arplast PV50 Propeller Motor (Mike Gregory) 4. 05:34 AM - Re: Arplast PV50 Propeller Motor (Robert L. Nuckolls, III) 5. 05:54 AM - Re: Arplast PV50 Propeller Motor (Jan de Jong) 6. 10:45 AM - Re: Battery disconnect with dual battery and trickle charger (Bill Watson) 7. 03:04 PM - Re: Battery disconnect with dual battery and trickle charger (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 01:40:28 AM PST US Subject: AeroElectric-List: Arplast PV50 Propeller Motor From: "BobD" The 6V Electric Motor on the Arplast PV50 propeller on my Europa has failed. Having researched the forums, there has been talk about replacing the 6V Motor with the 12V model, and I am putting together a MOD request to the UK LAA to do this. It seems sensible, as the aircraft provides 12V to the motor. However, I am not well versed in the skills required to compare the two models, so I hope someone here can look at the attached spec sheet for the motors, and let me know if they can find any reason not to do this. Conversely, any reasons why it may be a good idea would help with my submission to the LAA The current model is 2224U006SR, and I am looking at replacing this with a 2224U012SR I also wonder why the original Propeller manufacturer (no longer in business) would use a 6V motor on a 12V system (unless the 12V option wasn't available at the time)? -------- Bob Dawson Europa XS TG || 912 ULS || G-NHRJ || Dynon Skyview || PilotAware || SmartAss3 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=487487#487487 Attachments: http://forums.matronics.com//files/en_2224_sr_dff_206.pdf ________________________________ Message 2 _____________________________________ Time: 03:05:39 AM PST US Subject: Re: AeroElectric-List: Arplast PV50 Propeller Motor From: Jan de Jong If I read this correctly the 6V item has nominally: stall current 3.1A (6 / 1.94) stall torque 21.2 mNm as used: stall current 7.2A (14 / 1.94) stall torque about 50 mNm The 6V motor will only survive if used infrequently for short periods. There is a thermal time constant of 6.8 seconds that is of interest in this regard. For the 12V item the nominal values and the proposed 'as used' values are close together. That leads to good reliability, but also to less than half the torque Arplast apparently wanted. So. Most likely the 6V item must be used with care and the 12V item is probably not up to the task. IMHO. Jan de Jong #461 'back to building' On 2/9/2019 10:39 AM, BobD wrote: > > The 6V Electric Motor on the Arplast PV50 propeller on my Europa has failed. Having researched the forums, there has been talk about replacing the 6V Motor with the 12V model, and I am putting together a MOD request to the UK LAA to do this. It seems sensible, as the aircraft provides 12V to the motor. However, I am not well versed in the skills required to compare the two models, so I hope someone here can look at the attached spec sheet for the motors, and let me know if they can find any reason not to do this. Conversely, any reasons why it may be a good idea would help with my submission to the LAA > > The current model is 2224U006SR, and I am looking at replacing this with a 2224U012SR > > I also wonder why the original Propeller manufacturer (no longer in business) would use a 6V motor on a 12V system (unless the 12V option wasn't available at the time)? > > -------- > Bob Dawson > Europa XS TG || 912 ULS || G-NHRJ || Dynon Skyview || PilotAware || SmartAss3 > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=487487#487487 > > > Attachments: > > http://forums.matronics.com//files/en_2224_sr_dff_206.pdf > > ________________________________ Message 3 _____________________________________ Time: 05:15:59 AM PST US From: "Mike Gregory" Subject: RE: AeroElectric-List: Arplast PV50 Propeller Motor Bob, Jan is quite correct to warn that you are unlikely to get the stall torque needed to move the blades under flight loads with a 12v rated version of the fitted 6v motor. When visiting the factory of another VP prop manufacturer in 2000, I asked the same question: "Why are you using a 6v motor in a 12v electrical system" and was told that they needed to overdrive the 6v motor to get the torque necessary, but the duty cycle was low and the back-EMF reduced the current as soon as the motor was running. A number of things need to operate properly for this 6v motor to be reliable in service, in particular: - The flight loads must not cause the motor to struggle, so that the high starting current lasts for long enough to overheat the motor - this will depend on airspeed, blade shape, lubrication, etc. - The controller should not cause the system to hunt, i.e. make frequent movements to adjust the blade pitch, especially in the cruise, which can increase the duty cycle well beyond the design limit. The increased temperature and brush wear will be likely to cause premature failure. - To avoid hunting in the cruise, switching the controller to manual can help, but you then need to keep a check and make adjustments, or switch back to auto when the flight mode changes. - To find out if the motor is being overloaded, monitoring the drive current would indicate whether it was struggling whenever the controller was demanding a change in pitch, and the frequency of changes would readily show hunting. The controller may well have an indicator light to show when the motor is running. In short, I would not recommend changing from the 6v motor without knowing that the replacement would cope with the loads, and in any case not before exploring the operation of the controller and propeller in your aeroplane and the flight profiles you follow. Good luck! Mike -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jan de Jong Sent: 09 February 2019 11:15 Subject: Re: AeroElectric-List: Arplast PV50 Propeller Motor If I read this correctly the 6V item has nominally: stall current 3.1A (6 / 1.94) stall torque 21.2 mNm as used: stall current 7.2A (14 / 1.94) stall torque about 50 mNm The 6V motor will only survive if used infrequently for short periods. There is a thermal time constant of 6.8 seconds that is of interest in this regard. For the 12V item the nominal values and the proposed 'as used' values are close together. That leads to good reliability, but also to less than half the torque Arplast apparently wanted. So. Most likely the 6V item must be used with care and the 12V item is probably not up to the task. IMHO. Jan de Jong #461 'back to building' On 2/9/2019 10:39 AM, BobD wrote: > > The 6V Electric Motor on the Arplast PV50 propeller on my Europa has failed. Having researched the forums, there has been talk about replacing the 6V Motor with the 12V model, and I am putting together a MOD request to the UK LAA to do this. It seems sensible, as the aircraft provides 12V to the motor. However, I am not well versed in the skills required to compare the two models, so I hope someone here can look at the attached spec sheet for the motors, and let me know if they can find any reason not to do this. Conversely, any reasons why it may be a good idea would help with my submission to the LAA > > The current model is 2224U006SR, and I am looking at replacing this with a 2224U012SR > > I also wonder why the original Propeller manufacturer (no longer in business) would use a 6V motor on a 12V system (unless the 12V option wasn't available at the time)? > > -------- > Bob Dawson > Europa XS TG || 912 ULS || G-NHRJ || Dynon Skyview || PilotAware || SmartAss3 > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=487487#487487 > > > Attachments: > > http://forums.matronics.com//files/en_2224_sr_dff_206.pdf > > ________________________________ Message 4 _____________________________________ Time: 05:34:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Arplast PV50 Propeller Motor At 05:14 AM 2/9/2019, you wrote: > >So. Most likely the 6V item must be used with care and the 12V item >is probably not up to the task. > >IMHO. > >Jan de Jong >#461 'back to building' Agreed . . . Bob . . . ________________________________ Message 5 _____________________________________ Time: 05:54:34 AM PST US Subject: Re: AeroElectric-List: Arplast PV50 Propeller Motor From: Jan de Jong Maybe good to mention also that heat production goes with the square of the current... ________________________________ Message 6 _____________________________________ Time: 10:45:11 AM PST US Subject: Re: AeroElectric-List: Battery disconnect with dual battery and trickle charger From: Bill Watson On 1/26/2019 12:33 PM, Charlie England wrote: > On 1/26/2019 10:23 AM, Robert L. Nuckolls, III wrote: >>> >>> I bought a 'no name' SLA battery through ebay back in mid November >>> for a Kolb project that won't fly until spring. I just checked its >>> voltage, and it's still at 12.8V. How long do you plan for the plane >>> to sit between flights? While some have had decent luck using >>> 'maintainer' chargers on SLA batteries, many have seen greatly >>> reduced lifespans when using maintainers. If the battery technology >>> doesn't need it (extremely low self-discharge rate), why risk it? >>> Odyssey's technical documents will show you the self-discharge rate >>> for one of their healthy batteries. >> >> If you have a demonstrated incident of >> death-by-maintainer, then the maintainer >> was (1) badly designed or (2) defective. >> >> An 'ideal' recharge/maintenance plot >> looks like this: >> >> https://tinyurl.com/k6xr9mk >> >> Here's a measured performance on >> a Schumacher XC75 charger on a >> 100AH truck battery >> >> https://tinyurl.com/k6xr9mk >> >> Here's a plot on a Schumacher WM1562A >> on a 20AH SLVA >> >> https://tinyurl.com/mtqyhxb >> >> Here's a Battery Tender Jr. on a 7AH >> SVLA >> >> https://tinyurl.com/b4td78b >> >> While some do not closely follow the >> 'ideal' plots, they do achieve a top-off >> followed by a drop-and-hold to the >> maintenance level. I've been >> using various charger/maintainer >> products for decades on both vehicles >> and lab batteries with expected >> results: Some of my lab batteries are >> over ten years old and still deliver >> a substantial fraction of their >> name-plate capacity. I.e. still >> over 80%. >> >> I've yet to test any Harbor Freight >> maintainer that produces the necessary >> performance . . . doesn't mean that >> there are none . . . just that the >> two I tested went into the round-file >> and that was over 10 years ago. >> >> While it's true that well constructed >> SVLA batteries may not benefit greatly >> from the use of a maintainer, it's >> not a BAD thing to do either and >> in some cases a necessary thing to do. >> >> >> >> >> Bob . . . >> > Bob, > > No disagreement that if everything is 'right', it'll be ok. But. The > fact remains that quite a few a/c-application SLA users that have > practiced maintainer continuous use, report relatively short lived > batteries. on the other hand, I don't recall ever hearing a report of > short battery life from someone who *doesn't* have a maintainer in > continuous service, even in planes that aren't regularly flown. My a/c > fits the latter category; it often goes longer than a month without > flying, and I've never had an issue with short battery life. > > Given that SLAs can go many months with minimal self-discharge (begs > the question of need), and the risk of unintentional use of an > incorrect or defective charger, why go to the trouble? Now if it's > going to sit for a year... > > Charlie I was one of those people who ruined a number of O-680s with a Battery Tender branded maintainer. It was established that it was an earlier version than that being mentioned here, probably manufactured circa '85. I also managed to ruin a 680 by undercharging it in flight. I was just under the recommended minimum charging voltage for Odysseys and it slowly died. I have a dual alt/batt/bus setup so it was easy to compare it to the other battery. One lesson learned was not to put the LRC3 in such a difficult place to reach that you can't adjust the charging voltage. All of that was an awfully expensive way to learn what was already known. A situation I can cite that might call for use of a maintainer or top-off is where you shutdown without the battery being fully charged. I have 3 EFIS screens and the landing light among other things, sharing one bus. When I land at night followed by a long taxi, I can see the bus voltage on the one bus with the pad mounted secondary alternator, is low. I try to cross connect the 2 buses before landing at night but sometimes forget. When I forget, I try to top off the battery. Don't really know if it's a problem or not. Bill --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 7 _____________________________________ Time: 03:04:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Battery disconnect with dual battery and trickle charger >I was one of those people who ruined a number of O-680s with a >Battery Tender branded maintainer. It was established that it was an >earlier version than that being mentioned here, probably >manufactured circa '85. Hmmmm . . . didn't know they went back that far. Doubt that they were software driven. I didn't start using them until about 1998 . . . in fact, the top-off/ maintainer curves I've published were probably produced by one of my earliest examples. > > I try to cross connect the 2 buses before landing at night but > sometimes forget. When I forget, I try to top off the > battery. Don't really know if it's a problem or not. Do you know what the drain is on the battery . . . and for how long? Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.