AeroElectric-List Digest Archive

Sun 10/09/05


Total Messages Posted: 10



Today's Message Index:
----------------------
 
     1. 06:52 AM - Re: lean ops (Robert L. Nuckolls, III)
     2. 06:59 AM - Re: Positronic removal with hammer (Robert L. Nuckolls, III)
     3. 07:24 AM - Re: Re: Positronic removal with hammer (Bob White)
     4. 08:04 AM - Re: New comic book on circuit breaker issues (Ken)
     5. 08:05 AM - Re: IR alternator (Franz Fux)
     6. 10:52 AM - Re: IR alternator (Robert L. Nuckolls, III)
     7. 10:56 AM - Re: aggressive engine leaning (Robert L. Nuckolls, III)
     8. 11:19 AM - Re:In honor of the "Repeatable Experiment".  (Jerry2DT@aol.com)
     9. 11:48 AM - Re: Re:In honor of the "Repeatable ()
    10. 06:20 PM - Re: Re: aggressive engine leaning (George Braly)
 
 
 


Message 1


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    Time: 06:52:37 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: re: lean ops
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 10:46 PM 10/8/2005 -0500, you wrote: >--> AeroElectric-List message posted by: "George Braly" <gwbraly@gami.com> > >Bob, > >Not necessary to reduce power except that it might reduce the pressure >of the exhaust gases in a turbo'd engine and thereby reduce the amount >that gets into the heater plumbing. > >However, CO makes up about 4 to 9% of the exhaust when 50 to 150d F >rich of peak EGT. > >One of the primary sources of the efficiency of LOP operations comes >from further oxidizing the CO to COO (CO2) and it turns out that at 25 >to 50F LOP the level of CO in the exhaust stream is down about one order >of magnitude. Interesting! Thanks. I don't know where I was seeded with the notion that lean ops called for reduction in total power to "protect" the engine. I probably picked that up from a flight instructor years ago and we know that while flight instructors are whizzes at FARS, procedures and manipulating the airplane, their understanding of systems and underlying simple-ideas is often found lacking. Bob . . .


    Message 2


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    Time: 06:59:29 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Positronic removal with hammer
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 10:44 PM 10/8/2005 -0400, you wrote: >--> AeroElectric-List message posted by: CardinalNSB@aol.com > >Thank you Bob for the link, I was at least able to get an idea of the shape. > I went to the hobby store and got some thinwall tubing to try to emulate >the factory removal tool-it looks like a tube but has a spring loaded "gun" >inside it to punch out the contactor. I used a thinwall tube to go down >past >the "springs", then a small phillips inside the tube with some >gentle tapping >with a ballpeen hammer. (my wife always gets nervous when I use a hammer in >my aircraft repair). They popped out, some with a little more persuasion >than >others. These are the female solder cup types. I found a source for the >crimp type female, but not for the contactor block so I needed to get these >out. I stuck a few back in and they seem to work ok. Would it be >imprudent to >reuse these? How can I easily remove the old solder-propane torch, should I >heat them in a skillet, will hearing them harm them? Should I remove the >tiny spring loaded retaining clip before heating? These appear to be >brass, but >there is a lengthwise slit down the barrell which provides the tenion for >the male pen. You are to be commended for your resourcefulness. Sounds like you have a reasonable grasp of how these things fit together and an appreciation for their limits. To clean out the solder cups, hold the pin with a needle nose pliers and heat the joint with a soldering iron. Use some solder on the iron to 'wet' the contact between tip of iron and the pin. When the solder melts, shake the now loose wire and excess solder out of the pin. You can just fling it downward (careful not to throw hot globs of solder into your shoes or against polyester pants). Alternatively, striking the edge of your workbench with the pliers such that the open pin faces downward will accelerate the debris out of the solder cup and generally leave it quite clean and ready to accept the new wire. You need not disassemble the pin for any part of the recovery and reuse operations. Bob . . .


    Message 3


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    Time: 07:24:00 AM PST US
    From: Bob White <bob@bob-white.com>
    Subject: Re: Positronic removal with hammer
    --> AeroElectric-List message posted by: Bob White <bob@bob-white.com> One of the most effective ways to clean out a solder cup is to heat as you've described, then just drop the pin a foot or two onto a hard surface. Bob W. On Sun, 09 Oct 2005 08:58:59 -0500 "Robert L. Nuckolls, III" <nuckollsr@cox.net> wrote: > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> > > At 10:44 PM 10/8/2005 -0400, you wrote: > > >--> AeroElectric-List message posted by: CardinalNSB@aol.com > > > >Thank you Bob for the link, I was at least able to get an idea of the shape. > > I went to the hobby store and got some thinwall tubing to try to emulate > >the factory removal tool-it looks like a tube but has a spring loaded "gun" > >inside it to punch out the contactor. I used a thinwall tube to go down > >past > >the "springs", then a small phillips inside the tube with some > >gentle tapping > >with a ballpeen hammer. (my wife always gets nervous when I use a hammer in > >my aircraft repair). They popped out, some with a little more persuasion > >than > >others. These are the female solder cup types. I found a source for the > >crimp type female, but not for the contactor block so I needed to get these > >out. I stuck a few back in and they seem to work ok. Would it be > >imprudent to > >reuse these? How can I easily remove the old solder-propane torch, should I > >heat them in a skillet, will hearing them harm them? Should I remove the > >tiny spring loaded retaining clip before heating? These appear to be > >brass, but > >there is a lengthwise slit down the barrell which provides the tenion for > >the male pen. > > You are to be commended for your resourcefulness. Sounds like you > have a reasonable grasp of how these things fit together and an > appreciation for their limits. > > To clean out the solder cups, hold the pin with a needle nose pliers > and heat the joint with a soldering iron. Use some solder on the iron > to 'wet' the contact between tip of iron and the pin. When the solder > melts, shake the now loose wire and excess solder out of the pin. You can > just fling it downward (careful not to throw hot globs of solder into > your shoes or against polyester pants). Alternatively, striking the edge > of your workbench with the pliers such that the open pin faces downward > will accelerate the debris out of the solder cup and generally leave it > quite clean and ready to accept the new wire. You need not disassemble > the pin for any part of the recovery and reuse operations. > > Bob . . . > > > > > > > > -- http://www.bob-white.com N93BD - Rotary Powered BD-4 (real soon) Prewired EC2 Cables - http://www.roblinphoto.com/shop/


    Message 4


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    Time: 08:04:49 AM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: New comic book on circuit breaker issues
    --> AeroElectric-List message posted by: Ken <klehman@albedo.net> Wow! Enlightenment and understanding that can actually be used to make intelligent decisions. thankyou again Bob BTW I've also read that it is not possible to damage an engine by overleaning -provided power was not more than about 75%! Ken L. Robert L. Nuckolls, III wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> > >Thanks to Ken Baker's willingness to send me some very >good data on a circuit breaker failure he experienced, >I've been able to craft a new article on the topic. See: > >http://aeroelectric.com/articles/Breakers/Breakers.html > >If anyone else has breakers that might broaden our selection >(or de-selection) of parts, I'd be pleased to get exemplar >devices for study. > >Bob . . . > >


    Message 5


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    Time: 08:05:31 AM PST US
    From: "Franz Fux" <franz@lastfrontierheli.com>
    Subject: IR alternator
    --> AeroElectric-List message posted by: "Franz Fux" <franz@lastfrontierheli.com> Thanks Bob for your in depth answer, in your opinion, should the alternator be switched on before starting the engine or after, Franz -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: Re: AeroElectric-List: IR alternator --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 06:14 AM 10/8/2005 -0700, you wrote: >--> AeroElectric-List message posted by: "Franz Fux" ><franz@lastfrontierheli.com> > >Hi group, >I have an internally regulated 60v alternator from Vans as supplied in the >firewall foreward kit. I have wired it according to Bob's drawing Z11 with >the additional protection according to his drawing, using the >contactor(S701-1) he suggested. It is a prewired contactor that has a small >wire from the battery side to the smaller post where also the one side of >the diode terminates. Each time I turn on the battery this wire burns >through. I have checked all connections and they are according to Bob's >drawings. I am wondering if anybody could help me safe this puzzle and may >know what could be causing this short. The contactor you purchased had certain features pre-installed for the device to serve as a BATTERY contactor. If you study the z-figures for battery contactor wiring, you'll see that a wire between one of the fat terminals (battery side) connects to an adjacent small terminal. This wire is not shown in the old Z-24 depiction of a b-lead contactor. You need to remove this jumper for use as a b-lead contactor. Be aware that while Figure Z-24 (and documents describing installation of B&C over voltage protection products) increase risk for damage to an alternator if the alternator is switched off under load. The system you've installed WILL fulfill its intended purpose for absolute control of alternator combined with over-voltage protection. Just be aware that the alternator should not be switched off until after the engine stops except in cases of system malfunction where the alternator must be shut off due to OV condition -or- other reasons (like smoke in cockpit) where it's more important to get things electric shut down than it is to worry about hazards to the alternator. Studies are under way to devise an alternative to Z-24 so as to reduce if not eliminate risks to the alternator . . . in the mean time, you're on solid ground to proceed with an awareness of risks and operating procedures in place to mitigate those risks. Bob . . . -- --


    Message 6


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    Time: 10:52:16 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: IR alternator
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 08:02 AM 10/9/2005 -0700, you wrote: >--> AeroElectric-List message posted by: "Franz Fux" ><franz@lastfrontierheli.com> > >Thanks Bob for your in depth answer, in your opinion, should the alternator >be switched on before starting the engine or after, >Franz I don't think it's electrically critical and from what we understand about the startup dynamics under normal conditions, it doesn't matter. From the systems OPERATOR perspective, it seems practical and prudent to bring things up in steps so that the pilot can observe the effects of each new action separately. When I write POH supplements, I get high marks for orderly, one-step at a time instructions. So, lacking information suggesting that it's unwise, I'll say that the alternator be left OFF until the engine is running smoothly whereupon the pilot's attention can be shifted to cause an effects of bringing the electrical system up to full operation. Bob . . .


    Message 7


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    Time: 10:56:18 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: aggressive engine leaning
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 11:05 AM 10/9/2005 -0400, you wrote: >--> AeroElectric-List message posted by: Ken <klehman@albedo.net> > > Wow! >Enlightenment and understanding that can actually be used to make >intelligent decisions. >thankyou again Bob > >BTW I've also read that it is not possible to damage an engine by >overleaning -provided power was not more than about 75%! RAC's top engine guru is a few offices east of me in building. We'll see what he has to offer with respect to both historical and present fact. I'll hit up the guys over in flight test and our instructors in the flying club. It would be interesting to see if any of them can offer an attribution to this little nugget of aviation mythology . . . or who knows? We may find someone who want's to contest George's assertions. All in good fun and enlightenment as long as the gladiators bring data. Bob . . .


    Message 8


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    Time: 11:19:30 AM PST US
    From: Jerry2DT@aol.com
    Subject: Re:In honor of the "Repeatable Experiment".
    --> AeroElectric-List message posted by: Jerry2DT@aol.com Bob, I understand typically folks leave the external fan on the "77 Civic" type Autozone alternators referred to earlier. Will you be testing with/without the fan? I have one of these not flying yet, so inquiring minds... Jerry Cochran Wilsonville, OR Time: 08:50:00 AM PST US From: "Robert L. Nuckolls, III" <nuckollsr@cox.net> Subject: AeroElectric-List: In honor of the "Repeatable Experiment". --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> I've often used the term "repeatable experiment" much to the consternation and derision of some here on the list so it seems appropriate to take two lessons from the planned investigations into alternator performance and operating characteristics under abnormal conditions. I just received a shiny new ND alternator from one of the participants in this activity. Thank you Mr. Coggins! I'll endeavor to please you with a useful return on your investment. I've been talking with the folks who own the big variable speed drive and they're quite willing to give me access to it. However, after studying the brackets needed to mount a small, belt driven alternator on it and then constrict my study to time when they're open (my normal work hours) the time-to-first-test-results seems like it will be greater than if I were to build my own drive stand tailored to the task. I have a 2 hp DC motor and variable speed drive controller for it. My father-in-law is going to craft a fixture to hold the motor and alternator. In the mean time, I've shifted discussions with my old employer about trading some gray-matter time for an old environmental chamber they've relegated to the mod shop and are using as an oven for curing epoxies. This was the first chamber we ever owned and I was the first to operate the thing after it was purchased in 1976 for about $1200. If I can refurbish this ol' dog into operating condition, I'll end up with a tool that will allow me to test from -55C to +70C to explore temperature related issues with small articles that will fit in the chamber (it's about 1 cubic foot in volume). <<SNIP>>


    Message 9


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    Time: 11:48:33 AM PST US
    From: <nuckollsr@cox.net>
    Subject: Re:In honor of the "Repeatable
    Experiment". --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> Experiment". At 02:15 PM 10/9/2005 -0400, you wrote: >--> AeroElectric-List message posted by: Jerry2DT@aol.com > > >Bob, > >I understand typically folks leave the external fan on the "77 Civic" type >Autozone alternators referred to earlier. Will you be testing with/without >the fan? I have one of these not flying yet, so inquiring minds... > >Jerry Cochran >Wilsonville, OR The test article is fitted with internal, bi-directional fans. Most external fans have canted blades optimized for airflow in one direction. However, tests that we did at Electromech about 30 years ago showed that while the flow was reduced by turning the external fans "backwards", this was more than offset by pulley ratios on Lycoming engines that turned the alternator much faster than on cars. Now, having made this anecdote available, I'll suggest there is no substitute for data. It's not terribly difficult to thermocouple the stator wires and in some cases, diode heatsinks and GO MEASURE temperature rises under Vy climb at full load. I'm continually amazed at the numbers of threads over the years where builders are advised to take fans off 'cause they "run the wrong way". Or, "add blast tubes to avoid overheating", or any number of other remedies to mitigate an alternator failure . . . Yet not a single discussion talked about studies to measure operating temperatures or any suggestion that they be done. Alternator failures on OBAM aircraft are probably more rare than for certified ships where folks did a lot of testing to qualify 1960's technology onto spam cans. Those alternators fail mostly due to lack of exploitation of modern technology. OBAM aircraft have fewer failures probably because of the modern technology but we generally haven't a clue as to why they DO fail due to lack of data and a reluctance to go get it. It's easier to hip shoot the solutions . . . and if you blaze away at a problem long enough, odds are in your favor that you'll eventually "hit" it with the solution. Bob . . .


    Message 10


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    Time: 06:20:31 PM PST US
    Subject: Re: aggressive engine leaning
    From: "George Braly" <gwbraly@gami.com>
    --> AeroElectric-List message posted by: "George Braly" <gwbraly@gami.com> Bob, Actually, we have already had some of the Beech guys and the TCM guys and several FAA engine guys go through all of this. We teach a 16 hour weekend class on all of this about every other month. www.advancedpilot.com. It will be interesting to hear what your Beech guys say - - or how they "react". You should anticipate some howls and screams, and LOTS of opinions and old wive's tales - - but no data to the contrary. OTOH - - they will really dip their deals in deep do-do if they take that position - - because the A36 and the Baron IO-550 manual already SPECIFICALLY APPROVES LOP OPERATION at power settings up to about 78% power on the IO-550. They have been that way since 1984. Still are as of 2005. If the RAC/Beech folks take a different position - - then they need to re-write their own POH for those aircraft. Bob, keep in mind that there are only about 400 million hours of engine operation in piston powered aircraft with the engines operating at very high BMEPs (about equal to 90% of the BMEP of an IO-550) and the mixture set to about 50 to 75F LOP. Those engines typically went to about 3000 to 3600 hours between overhauls. The hard data is this: If you set an IO-550 engine up at 225 Hp and 75d F ROP, the peak internal cylinder pressures will be about 10% higher than the same engine at the same HP with the mixture set to about 50d F LOP. Further, the CHTs will be about 30 to 50d F HOTTER when ROP. The spark plug ceramic will be about 100 to 150dF hotter at the ROP setting (my data - - and yes, it really is hard to measure a thermocouple embedded in a spark plug ceramic putting out mv signals about 3/8ths of an inch from 16KV sparks happening at about 22Hz.) Regards, George -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: AeroElectric-List: Re: aggressive engine leaning --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 11:05 AM 10/9/2005 -0400, you wrote: >--> AeroElectric-List message posted by: Ken <klehman@albedo.net> > > Wow! >Enlightenment and understanding that can actually be used to make >intelligent decisions. >thankyou again Bob > >BTW I've also read that it is not possible to damage an engine by >overleaning -provided power was not more than about 75%! RAC's top engine guru is a few offices east of me in building. We'll see what he has to offer with respect to both historical and present fact. I'll hit up the guys over in flight test and our instructors in the flying club. It would be interesting to see if any of them can offer an attribution to this little nugget of aviation mythology . . . or who knows? We may find someone who want's to contest George's assertions. All in good fun and enlightenment as long as the gladiators bring data. Bob . . .




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