AeroElectric-List Digest Archive

Sun 10/20/13


Total Messages Posted: 13



Today's Message Index:
----------------------
 
     1. 06:19 AM - Re: Relay for Critical Power Feed (Eric M. Jones)
     2. 07:59 AM - Re: Re: Relay for Critical Power Feed (Robert L. Nuckolls, III)
     3. 08:19 AM - Re: Re: Relay for Critical Power Feed (Robert L. Nuckolls, III)
     4. 08:46 AM - Re: Relay for Critical Power Feed (Eric M. Jones)
     5. 09:05 AM - Re: Relay for Critical Power Feed (Eric M. Jones)
     6. 09:14 AM - Re: Relay for Critical Power Feed (Eric M. Jones)
     7. 09:45 AM - Re: Re: Relay for Critical Power Feed (Robert L. Nuckolls, III)
     8. 10:05 AM - Jabiru 2200 voltage regulator (Charles Deiterich)
     9. 12:00 PM - Re: Re: Relay for Critical Power Feed (Robert L. Nuckolls, III)
    10. 12:00 PM - Re: Re: Relay for Critical Power Feed (Robert L. Nuckolls, III)
    11. 12:07 PM - Jabiru 2200 voltage regulator again (Charles Deiterich)
    12. 01:02 PM - Re: EXP 2 Bus workaround (Ken)
    13. 03:00 PM - Re: Jabiru 2200 voltage regulator again (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 06:19:19 AM PST US
    Subject: Re: Relay for Critical Power Feed
    From: "Eric M. Jones" <emjones@charter.net>
    Don't use Type-70 Stancore-White-Rodgers-Emerson-Tyco contactors in your aircraft. The reasons are plentiful: They have a 122 deg F maximum ambient. They are not water or fuel proof, they won't open against high currents or voltages. They are position sensitive and have low G-withstands. Disregard the fact that they have been used and failing for many years. There are better ways to go. Bob N. and I have argued this for years. Here are some excerpts from the archives: --Relay mounting. Type 70 Stancor Rodgers White Emerson Tyco. See: http://www.alliedelec.com/Images/Products/Datasheets/BM/STANCOR/Stancor_Industrial-Control_5760005.pdf So the manufacturer says, "mount plunger vertical, cap down". I checked into the engineering data on this part and of course the corporate conglomeratization has destroyed the engineering knowledge that built the part. The manufacturer PROMISED they'd get back to me.....BUT It's not DO-160 bubela. And it's only 122 deg F max operating temp. Etc. etc. I spent many hours tracking down the designers of this Stancor-White-Rogers Emerson Tyco Type-70. The only info that remains available seems to be the present specs. The available newly produced Type-70 specs simply make it unsuitable. Will it work, Yes. Will it fail? Yes, sooner than you'd like. It is entirely possible that Cessna had a custom model. Is Cessna still using these? Possibly, but certificated a/c tend to use old original technology until it bleeds. There's no reason you should follow them. The Kilovac Czonkas II's are made in many types. There is a marine model too that is perfectly usable. (Blue Sea Systems p/n 9012) But I don't have stock in Kilovac. There are many makers of newer stuff [Gigavac has come out with similar contactors]. For my airplane, I'll use a Flaming River Battery switch if I can, and an EV200 otherwise.... ps: Guess how Kilovac and Gigavac clamp coil voltages generated from the collapsing magnetic field? That's right...internal bidirectional zeners. "Everything you've learned in school as "obvious" becomes less and less obvious as you begin to study the universe. For example, there are no solids in the universe. There's not even a suggestion of a solid. There are no absolute continuums. There are no surfaces. There are no straight lines." - R. Buckminster Fuller -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410914#410914


    Message 2


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    Time: 07:59:13 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Relay for Critical Power Feed
    At 08:18 AM 10/20/2013, you wrote: > >Don't use Type-70 Stancore-White-Rodgers-Emerson-Tyco contactors in >your aircraft. The reasons are plentiful: They have a 122 deg F >maximum ambient. They are not water or fuel proof, they won't open >against high currents or voltages. They are position sensitive and >have low G-withstands. Disregard the fact that they have been used >and failing for many years. There are better ways to go. Bob N. and >I have argued this for years. Here are some excerpts from the archives: "Better" is non quantitative. Just a few weeks ago I received a failed, 70-series contactor removed from a 70's model Cessna. The owner believed that it was the original contactor. We did a tear down and discovered that indeed, the contacts had become intermittent due to corrosion on contacts exacerbated by ingress of moisture. Mechanically the device was intact and functional . . . after 30+ years of service. Emacs! Here's the mating set of contacts . . . Emacs! For a device that has been operated for 30+ years "outside the spec sheet" envelope of limits it looks pretty good to me. Would this Cessna owner be well advised to install something "better"? If "better" means that some other device will not succumb to moisture (sealed contact chamber) and it has higher ambient temperature ratings, then yes, this carry-over from the 1940's has some peers with improvements that have evolved over time . . . often crafted to meet the needs of a more antagonistic environment. But when cherry-picking of features that are "better" becomes a driving force in our decision making processes, then other authors on this List could opine that one should avoid the IO-360 in favor of some newer technology. Or perhaps we are well advised to abandon panel mounted switches . . . We gave up these switches Emacs! in favor of these . . . Emacs! For reasons that are fairly obvious. But consider the constellation of simple-ideas that come with the use of this part in your airplane: Emacs! There are 10 new metallic joints added to every current carrying path by the use of these switches. That's a fist-full of new opportunities for failure. But each opportunity for failure is exploited by environmental conditions and craftsmanship of the installer. These switches HAVE suffered some interesting failures . . . Emacs! Question: Have switches of this genre ever bubbled to the surface as a hazard so egregious as to generate an AD against hundreds of thousands of such devices flying for the past 70 years? This switch has suffered that dubiou honor . . . Emacs! Every owner of a Baron or Bonanza has a new item on his/her worry-list due to an un-foreseen deficiency in the design . . . a deficiency that took decades of field service before it bubbled up and people-paid- to-worry took notice. Even people-paid-to-worry have not banned the humble ol' workhorse that is the 70-series contactor from flying aboard airplanes. We can sing the ballad of dueling specsheets but the bottom line is that this product has a SERVICE HISTORY that demonstrates it to be good value. I.e. performance traded against cost of ownership while being attentive to increased risks. Since we're ALL building failure tolerant electrical systems I can confidently suggest that consideration of "better" contactors is driven more by our desire to own and drive a Benz as opposed to a Ford . . . in spite of the fact that both vehicles have high order probability of getting us from point A to point B over 15 years and 200,000 miles at low risk . . . but with markedly different costs of ownership. Everything Eric has offered is true. The point of this discussion . . . indeed the point of this List is to sift the simple-ideas of any recipe for success and make decisions based on cost of ownership weighed against risk while sprinkling in some personal preferences for V-Power or EXP-Bus in with the gaggle of fuses and toggle switches. Just as S-K vs. Harbor Freight tools are judged in the marketplace, the value of a recipe-for success in our airplanes is demonstrated in the air. It's not WHAT we choose to use but the UNDERSTANDING we bring to airplane to keep OPERABILITY high, RISKS low while fitting COST of ownership to our own bank accounts. The 70-series contactor has demonstrated itself not to be a black hat lurking behind a rock awaiting the opportunity to give you a bad day in the cockpit. In 50 years of hammering on airplanes I can confidently assert that the greatest risks for failure to perform are human factors issues of installation, maintenance or operation. Failure to perform based inattention to specifications is VERY low on the list things cause pilots to break a sweat while airborne. Failure tolerant design strives to make any failure a MAINTENANCE and COST OF OWNERSHIP issue as opposed to a reason for breaking a sweat. Bob . . .


    Message 3


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    Time: 08:19:49 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Relay for Critical Power Feed
    > >I spent many hours tracking down the designers of this >Stancor-White-Rogers Emerson Tyco Type-70. Those guys died years ago . . . > The only info that remains available seems to be the present > specs. The available newly produced Type-70 specs simply make it > unsuitable. Will it work, Yes. Will it fail? Yes, sooner than you'd like. Quantify "sooner" and "like" . . . and lay foundation for those numbers. >It is entirely possible that Cessna had a custom model. They did not. Everything Cessna purchased in those days were catalog items folded into the qualified parts stream by virtue of words and illustrations on a piece of paper (we called them C-Drawings). Beech did the same thing on the W-31 breaker-switches. I did the same thing at Electro-Mech. But when C-H was selling thousands per year to Beech and Cessna versus hundreds of thousands per year to customers unwashed by the FARS, who do you think drove design decisions? >Is Cessna still using these? I'll have access to Cessna's great data-base-in-the-sky in a few weeks. I'll see what is being offered as spares for a 1970 C-172. >Possibly, but certificated a/c tend to use old original technology >until it bleeds. Does the IO-360 bleed? Has the lead-acid battery been relegated to the pages of aviation history? Has the incandescent landing light been pried out and replaced with LED as a hazard to the airframe and occupants? >ps: Guess how Kilovac and Gigavac clamp coil voltages generated from >the collapsing >magnetic field? That's right...internal bidirectional zeners. We explored the value of Benz versus Ford style coil suppression about 13 years ago. I went to the bench and did qualitative and quantitative measurements on the differences in performance and benefits derived therefrom. Did you find errors in either my process, measurement or reasoning? http://tinyurl.com/nva2xdy http://tinyurl.com/25wjo7w http://tinyurl.com/jwxxav8 Bob . . .


    Message 4


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    Time: 08:46:48 AM PST US
    Subject: Re: Relay for Critical Power Feed
    From: "Eric M. Jones" <emjones@charter.net>
    Your photo of the 30 year old contactor discloses: 30 years ago they looked like they were built better. The one you show is not the same one that is being used now. I stand my ground: Published specification for the Type-70 contactor say not to use it in the applications for which it is being used. Regardless of the fact that one can get away with it, better solutions are at hand. > Does the IO-360 bleed? Has the lead-acid battery been relegated to the pages of aviation history? Has the incandescent landing light been pried out and replaced with LED as a hazard to the airframe and occupants? > Strawman arguments Bob. You can do better. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410920#410920


    Message 5


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    Time: 09:05:51 AM PST US
    Subject: Re: Relay for Critical Power Feed
    From: "Eric M. Jones" <emjones@charter.net>
    Attached disassembled Type-70 (minus cap). -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410921#410921 Attachments: http://forums.matronics.com//files/type_70_411.jpg


    Message 6


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    Time: 09:14:56 AM PST US
    Subject: Re: Relay for Critical Power Feed
    From: "Eric M. Jones" <emjones@charter.net>
    Attached disassembled Type-70 (minus cap and copper coil). A long cost-cutting way down from the part you show. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410923#410923 Attachments: http://forums.matronics.com//files/type_70_119.jpg


    Message 7


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    Time: 09:45:08 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Relay for Critical Power Feed
    Been having some problems with cut-n-paste between PhotoShop and my email client . . . the email client doesn't always keep the ducks lined up. The workaround seems to be to save the image to hard drive and then import to the email client as a file . . . Reposted with corrected images . . . At 08:18 AM 10/20/2013, you wrote: > >Don't use Type-70 Stancore-White-Rodgers-Emerson-Tyco contactors in >your aircraft. The reasons are plentiful: They have a 122 deg F >maximum ambient. They are not water or fuel proof, they won't open >against high currents or voltages. They are position sensitive and >have low G-withstands. Disregard the fact that they have been used >and failing for many years. There are better ways to go. Bob N. and >I have argued this for years. Here are some excerpts from the archives: "Better" is non quantitative. Just a few weeks ago I received a failed, 70-series contactor removed from a 70's model Cessna. The owner believed that it was the original contactor. We did a tear down and discovered that indeed, the contacts had become intermittent due to corrosion on contacts exacerbated by ingress of moisture. Mechanically the device was intact and functional . . . after 30+ years of service. Emacs! Here's the mating set of contacts . . . Emacs! For a device that has been operated for 30+ years "outside the spec sheet" envelope of limits it looks pretty good to me. Would this Cessna owner be well advised to install something "better"? If "better" means that some other device will not succumb to moisture (sealed contact chamber) and it has higher ambient temperature ratings, then yes, this carry-over from the 1940's has some peers with improvements that have evolved over time . . . often crafted to meet the needs of a more antagonistic environment. But when cherry-picking of features that are "better" becomes a driving force in our decision making processes, then other authors on this List could opine that one should avoid the IO-360 in favor of some newer technology. Or perhaps we are well advised to abandon panel mounted switches . . . We gave up these switches Emacs! in favor of these . . . Emacs! For reasons that are fairly obvious. But consider the constellation of simple-ideas that come with the use of this part in your airplane: Emacs! There are 10 new metallic joints added to every current carrying path by the use of these switches. That's a fist-full of new opportunities for failure. But each opportunity for failure is exploited by environmental conditions and craftsmanship of the installer. These switches HAVE suffered some interesting failures . . . Emacs! Question: Have switches of this genre ever bubbled to the surface as a hazard so egregious as to generate an AD against hundreds of thousands of such devices flying for the past 70 years? This switch has suffered that dubiou honor . . . Emacs! Every owner of a Baron or Bonanza has a new item on his/her worry-list due to an un-foreseen deficiency in the design . . . a deficiency that took decades of field service before it bubbled up and people-paid- to-worry took notice. Even people-paid-to-worry have not banned the humble ol' workhorse that is the 70-series contactor from flying aboard airplanes. We can sing the ballad of dueling specsheets but the bottom line is that this product has a SERVICE HISTORY that demonstrates it to be good value. I.e. performance traded against cost of ownership while being attentive to increased risks. Since we're ALL building failure tolerant electrical systems I can confidently suggest that consideration of "better" contactors is driven more by our desire to own and drive a Benz as opposed to a Ford . . . in spite of the fact that both vehicles have high order probability of getting us from point A to point B over 15 years and 200,000 miles at low risk . . . but with markedly different costs of ownership. Everything Eric has offered is true. The point of this discussion . . . indeed the point of this List is to sift the simple-ideas of any recipe for success and make decisions based on cost of ownership weighed against risk while sprinkling in some personal preferences for V-Power or EXP-Bus in with the gaggle of fuses and toggle switches. Just as S-K vs. Harbor Freight tools are judged in the marketplace, the value of a recipe-for success in our airplanes is demonstrated in the air. It's not WHAT we choose to use but the UNDERSTANDING we bring to airplane to keep OPERABILITY high, RISKS low while fitting COST of ownership to our own bank accounts. The 70-series contactor has demonstrated itself not to be a black hat lurking behind a rock awaiting the opportunity to give you a bad day in the cockpit. In 50 years of hammering on airplanes I can confidently assert that the greatest risks for failure to perform are human factors issues of installation, maintenance or operation. Failure to perform based inattention to specifications is VERY low on the list things cause pilots to break a sweat while airborne. Failure tolerant design strives to make any failure a MAINTENANCE and COST OF OWNERSHIP issue as opposed to a reason for breaking a sweat. Bob . . .


    Message 8


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    Time: 10:05:47 AM PST US
    From: Charles Deiterich <cffd66@yahoo.com>
    Subject: Jabiru 2200 voltage regulator
    I have Jabiru 2200 serial # 988 which has the 10 amp alternator.- I have the circuit diagram of the Kabota regulator.- Is there a writeup on how t he regulator works?- It appears to have a differential amplifier to sense the bus voltage and the then compares it to the AC coming from the alterna tor.- I just don't understand how the zener diode provides a reference wi thout a resistor to control the current through the zener and also how the AC wave is compared to the reference.- But then again I have always have had problems with PNP circuits.=0AChuck D.


    Message 9


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    Time: 12:00:01 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Relay for Critical Power Feed
    At 11:10 AM 10/20/2013, you wrote: > >Attached disassembled Type-70 (minus cap and copper coil). A long >cost-cutting way down from the part you show. Really? Are we privy to the conversations that transpired during the last 50 years worth of engineering/management/ manufacturing/marketing meetings wherein the design features of this product like were decided? I'll invite our readers to review the library of 70 series photos at http://tinyurl.com/kcc26jt These photos only go back to about 1960 . . . it seems likely that a 1940 tear-down would show yet other differences. I would guess that this product line has enjoyed a host of cost-cutting changes. Advancements in materials and automation are nearly always responsible for reductions in cost and/or improvements in meeting design goals. But consider that of the trio of failure teardowns illustrated in the library of pictures, 2 failures were the result of assembly error . . . a human factor I cited earlier today. The third failure occurred at or beyond any practical expectations for service life on the product . . . the thing operated as designed and expired gracefully (random intermittent). Further it was not a player in the classic trio of conditions that precede so many sad events in aviation and elsewhere. You seem to use the phrase "cost cutting" as an epithet. I have participated in dozens of tasks where cost-cutting was a mission imperative. However, in no instance was degradation of service life or performance considered a component of the acceptable solution. More often than not, the upgrade reduced costs while improving on the value of the product. Bob . . .


    Message 10


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    Time: 12:00:04 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Relay for Critical Power Feed
    > > Does the IO-360 bleed? Has the lead-acid battery been relegated > to the pages of aviation history? Has the incandescent landing > light been pried out and replaced with LED as a hazard to the > airframe and occupants? > >Strawman arguments Bob. You can do better. Okay, strike that paragraph. What about the others? Bob . . .


    Message 11


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    Time: 12:07:56 PM PST US
    From: Charles Deiterich <cffd66@yahoo.com>
    Subject: Jabiru 2200 voltage regulator again
    I have Jabiru 2200 serial # 988 which has the 10 amp alternator.- I have the circuit diagram of the Kabota regulator.- Is there a writeup on how t he regulator works?- It appears to have a differential amplifier to =0Ase nse the bus voltage and the then compares it to the AC coming from the alte rnator.- I just don't understand how the zener diode provides a =0Arefere nce without a resistor to control the current through the zener =0Aand also how the AC wave is compared to the reference.- But then again I have alw ays have had problems with PNP circuits.=0AChuck D.=0A=0A=0AFurther study s hows that Q1 and Q2 are to light a low voltage lite and are not part of a d ifferential amplifier.- Q3 and Q4 are for the regulator.- My comment ab out the current limit on the zener still stands.- circuit is from: http:/ /www.aeroelectric.com/Pictures/Schematics/PM_Regulator/Kubota_Schematic.jpg =0A=0AChuck D.=0A


    Message 12


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    Time: 01:02:57 PM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: EXP 2 Bus workaround
    If this question was for Ken... On my one off z14 architecture 4 cylinder soob, I run two ecu's all the time, one off each little battery. Two sets of injectors. Whichever set of injectors is fed +12 volts flows fuel. If both are on by mistake the engine loses some power but continues to run but a bit rough. I'm happy with two switches for this. I don't need or want one either/or switch although initially I was thinking that two mechanically interconnected switches might be OK. Similar with ignition. Whichever set of DIS coils is fed +12 volts feeds the single plugs through MSD and homemade (polarity issue) HV coil joiners. Both can be left on indefinitely or for landing and take off but I only use one at a time. In steady state cruise 18amps runs my airplane. That includes running the VHF radio, transponder, intercom, engine monitor, gps, and maybe an amp (or less) to the battery. If I did not have two alternators I'd size the battery for about 15 amps for alternator failed operation. Injectors are about 12 ohms and run 80% duty at full power and in my case about 50% duty in cruise. Ignition is about 5 amps at full power but a little less in cruise. Similarly the injectors draw a little bit more at full power but in total only maybe an amp or less difference between full power and cruise for the complete system. My system would certainly be overkill for most folks but it has some unique advantages in terms of simple emergency procedures, troubleshooting, and redundancy. With recycled parts, the dollar and weight cost was trivial if not the labor. 530 flight hours on the Murphy Rebel as of this morning. Ken On 19/10/2013 9:09 PM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 04:01 PM 10/14/2013, you wrote: > >> On Oct 14, 2013, at 12:16 PM, Ken wrote: >> >>> You are in the ballpark Fred but it's probably safe to round down to >>> 20 amps for a no alternator battery life calculation. >> >> Ken...thank you for your "3rd party validation"...at this stage of the >> game, I'd rather be conservative, and I'm looking forward to Bob's >> assessment. > > I think I'm down to the last missing data point. > > How do you switch between ECU modules? Do you have > a wiring diagram of this feature you can sketch or scan > to share? > > > Bob . . . > >


    Message 13


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    Time: 03:00:54 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Jabiru 2200 voltage regulator again
    > >Further study shows that Q1 and Q2 are to light a low voltage lite >and are not part of a differential amplifier. Q3 and Q4 are for the >regulator. My comment about the current limit on the zener still >stands. circuit is from: >http://www.aeroelectric.com/Pictures/Schematics/PM_Regulator/Kubota_Schematic.jpg Yes, the circuit was dissected into two functions at: http://tinyurl.com/c8usyw2 http://tinyurl.com/c6doa97 . . . and you're right. The base-emitter junction of Q4 in series with the hopefully small dynamic resistance of the zener places the transistor at serious risk. This design would not even come close to passing DO160 input voltage tests. But then, not many garden tractors are subject to the kinds of trash on the bus as airplanes. I've not seen a schematic for a PM regulator that offers warm-fuzzy feelings to an airplane jockey. These bang-bang regulators have proven quite sufficient for the lawn equipment markets and few folks have complained about them in airplanes . . . at least few to none here on the List. They may have a field service history one step above dismal but not articulated here. If you're pondering a DIY project for a PM regulator, consider adding some impedance in series with the base of Q4. It doesn't need to be very big. The way this thing is wired, the zener's operating current is VERY low . . . a milliamp or less. Also poor design practice . . . this is not up on the knee for predictable conduction at the rated voltage. So 100 ohms in series would protect the transistor and have very little effect on regulation. An adjustable regulator might modify the input circuit to include a potentiometer which would add useful base current protection for Q4. If you're up to brass-boarding some experiments, I've had a few ideas for an upgrading of the circuit's performance. Bob . . .




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