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BuckWynd

Joined: 27 Nov 2007
Posts: 10

Posted: Tue Nov 27, 2007 12:02 pm Post subject: Z-12 and Z-13/20 features questions

It's that time in my building process where I'm making the big decisions regarding the electrical system. At this point I like the idea of a 20-amp aux alternator in addition to the main alternator. I want to see if I've got my design concepts straight here. Maybe someone can help.



1. What is the main benefit of a Z-13/20 over a Z-12 system? Is it that with a Z-12, you must manually load-shed your system in the event of a main alternator failure? Both designs have 20-amp aux alternators, both have one main battery, and both have E-buses. The biggest difference I can see is that the Z-13/20 has an SPDT "E-Bus Alt Master" switch controlling an E-bus contactor, while the Z-12 merely has a switch powering the E-bus from the main battery. 



2. This one might help me answer the previous question for myself: On the Z-13/20 system, is the "E-bus Alt Master" switch intended to remain off until needed, or does it stay on during normal ops, allowing the 20A alternator to pick up the E-bus load after a failure of the main alternator?



3. Although my planned E-bus load is approximately 10A right now, I'd definitely consider lowering it below 8A, and use a SD-8 PM alternator and the Z-13/8 design, if the complexity and weight were big enough of an issue. While perusing the two designs side-by-side, I could not help but notice that the 8A alternator requires the use of a voltage regulator, a 20-50uF capacitor, an over-voltage module, a contactor and the related connectors and wiring for these items. The 20A alternator requires just an LR-3 controller, apparently. Is the weight savings of the 8A alternator worth the tradeoff in less individual components and wiring that is apparently required for a 20A one? I can't find the weights of these items anywhere. 



Thanks to the members of this list for a great learning resource!

_________________
Buck Wyndham
RV-8 N18XL (working on fuselage & systems)
Northern Illinois

nuckolls.bob(at)cox.net
Guest

Posted: Tue Nov 27, 2007 2:02 pm Post subject: Z-12 and Z-13/20 features questions

At 12:02 PM 11/27/2007 -0800, you wrote:



 	  Quote: 	
		  



It's that time in my building process where I'm making the big decisions 

regarding the electrical system. At this point I like the idea of a 20-amp 

aux alternator in addition to the main alternator. I want to see if I've 

got my design concepts straight here. Maybe someone can help.



1. What is the main benefit of a Z-13/20 over a Z-12 system? Is it that 

with a Z-12, you must manually load-shed your system in the event of a 

main alternator failure? Both designs have 20-amp aux alternators, both 

have one main battery, and both have E-buses. The biggest difference I can 

see is that the Z-13/20 has an SPDT "E-Bus Alt Master" switch controlling 

an E-bus contactor, while the Z-12 merely has a switch powering the E-bus 

from the main battery.


	


   First, why are you considering the SD20 in the first

   place. How do you plan to use your airplane and what

   equipment do you plan to install that drives a

   10+ amps ebus loads?

 	  Quote: 	
		  2. This one might help me answer the previous question for myself: On the 

Z-13/20 system, is the "E-bus Alt Master" switch intended to remain off 

until needed, or does it stay on during normal ops, allowing the 20A 

alternator to pick up the E-bus load after a failure of the main alternator?



3. Although my planned E-bus load is approximately 10A right now, I'd 

definitely consider lowering it below 8A, and use a SD-8 PM alternator and 

the Z-13/8 design, if the complexity and weight were big enough of an 

issue. While perusing the two designs side-by-side, I could not help but 

notice that the 8A alternator requires the use of a voltage regulator, a 

20-50uF capacitor, an over-voltage module, a contactor and the related 

connectors and wiring for these items. The 20A alternator requires just an 

LR-3 controller, apparently. Is the weight savings of the 8A alternator 

worth the tradeoff in less individual components and wiring that is 

apparently required for a 20A one? I can't find the weights of these items 

anywhere.


	


   I'm having trouble imagining any ENDURANCE-bus load

   that makes addition of 6 pounds and ~$700 to build

   costs an attractive notion.



   Let's talk about that before we dissect architectures.



   Bob . . .

BuckWynd

Joined: 27 Nov 2007
Posts: 10

Posted: Tue Nov 27, 2007 6:41 pm Post subject: Re: Z-12 and Z-13/20 features questions

 	  nuckolls.bob(at)cox.net wrote: 	
		    First, why are you considering the SD20 in the first

   place. How do you plan to use your airplane and what

   equipment do you plan to install that drives a

   10+ amps ebus loads? 	


 	  Quote: 	
		     I'm having trouble imagining any ENDURANCE-bus load

   that makes addition of 6 pounds and ~$700 to build

   costs an attractive notion.



   Let's talk about that before we dissect architectures.

	


Hi Bob,



To answer your questions, I'm considering installing an SD20 because, frankly, a). it's available and b). I'm comfortable with a bit of "overkill" when it comes to electrical power generation. Cost is simply not an issue, and weight-saving, while important to me, is secondary to building a robust electrical system. (As an aside, I'm saving over 30 pounds from a "stock" RV-8 by using a lightweight composite prop and lightweight aluminum landing gear. Other improvements will save even more weight.)



My airplane will be used for a lot of day VFR, but also some fairly regular IFR cross-country, and occassional night flying. It wil be highly-electrical dependent, with dual GRT EFIS displays, a backup Dynon D-10A, a Garmin 430, a Garmin SL-30, a Garmin 330 transponder, a PMA9000 audio panel, and a Trutrak Digiflight II VSVG autopilot.  Not all of these items are on the E-bus, of course, but some are.



My concept of the E-bus (and I do NOT mind calling it an Essential Bus -- it does not scare me or exude a negative connotation -- it's what every sophisticated airplane I've flown in 28 years calls it) is to cover the loads of the aircraft's important avionics and some carefully selected accessories while I comfortably divert to a suitable airport where maintenance can be undertaken. I do not necessarily want to continue to my planned destination -- that goes against my personal ideas of safety. (That topic is a whole other thread which I do not want to get into here...)



So there you have it -- I guess I'm attracted to a 20-amp alternator because it exists; because installing one would allow me a margin of "comfortable operability" without utilizing my main battery's capacity one iota while I'm diverting to a suitable airport; and because cost is not part of the equation.



So what remains in the equation are weight, complexity (number of parts, wires and connectors), and reliability. 



If you need to have a complete list of my E-bus loads, I'll certainly post them here in a day or so when I return home and consult my notebook...



Thanks in advance. I truly appreciate all input on this matter.



Buck

_________________
Buck Wyndham
RV-8 N18XL (working on fuselage & systems)
Northern Illinois

nuckolls.bob(at)cox.net
Guest

Posted: Tue Nov 27, 2007 8:50 pm Post subject: Z-12 and Z-13/20 features questions

At 06:41 PM 11/27/2007 -0800, you wrote:



 	  Quote: 	
		  

nuckolls.bob(at)cox.net wrote:

 >   First, why are you considering the SD20 in the first

 >    place. How do you plan to use your airplane and what

 >    equipment do you plan to install that drives a

 >    10+ amps ebus loads?





 >    I'm having trouble imagining any ENDURANCE-bus load

 >    that makes addition of 6 pounds and ~$700 to build

 >    costs an attractive notion.

 >

 >    Let's talk about that before we dissect architectures.

 >



Hi Bob,



To answer your questions, I'm considering installing an SD20 because, 

frankly, a). it's available and b). I'm comfortable with a bit of 

"overkill" when it comes to electrical power generation. Cost is simply 

not an issue, and weight-saving, while important to me, is secondary to 

building a robust electrical system. (As an aside, I'm saving over 30 

pounds from a "stock" RV-8 by using a lightweight composite prop and 

lightweight aluminum landing gear. Other improvements will save even more 

weight.)



My airplane will be used for a lot of day VFR, but also some fairly 

regular IFR cross-country, and occassional night flying. It wil be 

highly-electrical dependent, with dual GRT EFIS displays, a backup Dynon 

D-10A, a Garmin 430, a Garmin SL-30, a Garmin 330 transponder, a PMA9000 

audio panel, and a Trutrak Digiflight II VSVG autopilot.  Not all of these 

items are on the E-bus, of course, but some are.


	


   Which ones are and what are their en-route

   current requirements?

 	  Quote: 	
		  My concept of the E-bus (and I do NOT mind calling it an Essential Bus -- 

it does not scare me or exude a negative connotation -- it's what every 

sophisticated airplane I've flown in 28 years calls it) is to cover the 

loads of the aircraft's important avionics and some carefully selected 

accessories while I comfortably divert to a suitable airport where 

maintenance can be undertaken. I do not necessarily want to continue to my 

planned destination -- that goes against my personal ideas of safety. 

(That topic is a whole other thread which I do not want to get into here...)



So there you have it -- I guess I'm attracted to a 20-amp alternator 

because it exists; because installing one would allow me a margin of 

"comfortable operability" without utilizing my main battery's capacity one 

iota while I'm diverting to a suitable airport; and because cost is not 

part of the equation.



So what remains in the equation are weight, complexity (number of parts, 

wires and connectors), and reliability.



If you need to have a complete list of my E-bus loads, I'll certainly post 

them here in a day or so when I return home and consult my notebook...


	


    Hmmmm . . . if you really want the SD-20, then

    go with Z-12. Z-13/20 sucks and I'm taking it out

    at the next revision. It wasn't a very good idea

    in the first place. . .  In fact, I think I'll

    take it out of Appendix Z now.



    Bob  . . .

Peter Laurence

Joined: 10 Jan 2006
Posts: 50

Posted: Wed Nov 28, 2007 5:02 am Post subject: Z-12 and Z-13/20 features questions

Buck,



 I'll put my three cents in here.



Having wired two aiplanes as per Bob's drawings, I 've wonderd whether the E 

buss concept was   necessary.  One wiring project was  a velocity with a 

B&c 40 amp alt on the vacuum pad, a 60  main with an E buss. It seems that 

the only time one will have to use the E buss is 1. failure of the battery 

contactor (and that's another issue  ) or 2. failure of both alternators. 

For that to happen your engine is probably not running!.



If your going to use a dual alternators, split the buses and eliminate the E 

buss. Or, use a main buss and eliminate the E buss.

I'm wiring my RV9A and decided that all devices will go on the main buss.

In the event of an alt failure, pull the field breaker and if necessary, 

turn off the battery contactor. Have a 50 to 60 amp breaker/switch from the 

battery plus to the main buss. You become the E buss and shut down non 

essentail devices--It takes about 5 to 10 seconds.

Close the breaker and you have an essential buss. It seems to me that at one 

time or another, all these instruments are "essential" to flight.

Peter



 	  Quote: 	
		  

 Hi Bob,



 To answer your questions, I'm considering installing an SD20 because, 

 frankly, a). it's available and b). I'm comfortable with a bit of 

 "overkill" when it comes to electrical power generation. Cost is simply 

 not an issue, and weight-saving, while important to me, is secondary to 

 building a robust electrical system. (As an aside, I'm saving over 30 

 pounds from a "stock" RV-8 by using a lightweight composite prop and 

 lightweight aluminum landing gear. Other improvements will save even more 

 weight.)



 My airplane will be used for a lot of day VFR, but also some fairly 

 regular IFR cross-country, and occassional night flying. It wil be 

 highly-electrical dependent, with dual GRT EFIS displays, a backup Dynon 

 D-10A, a Garmin 430, a Garmin SL-30, a Garmin 330 transponder, a PMA9000 

 audio panel, and a Trutrak Digiflight II VSVG autopilot.  Not all of these 

 items are on the E-bus, of course, but some are.



 My concept of the E-bus (and I do NOT mind calling it an Essential Bus --  

 it does not scare me or exude a negative connotation -- it's what every 

 sophisticated airplane I've flown in 28 years calls it) is to cover the 

 loads of the aircraft's important avionics and some carefully selected 

 accessories while I comfortably divert to a suitable airport where 

 maintenance can be undertaken. I do not necessarily want to continue to my 

 planned destination -- that goes against my personal ideas of safety. 

 (That topic is a whole other thread which I do not want to get into 

 here...)



 So there you have it -- I guess I'm attracted to a 20-amp alternator 

 because it exists; because installing one would allow me a margin of 

 "comfortable operability" without utilizing my main battery's capacity one 

 iota while I'm diverting to a suitable airport; and because cost is not 

 part of the equation.



 So what remains in the equation are weight, complexity (number of parts, 

 wires and connectors), and reliability.



 If you need to have a complete list of my E-bus loads, I'll certainly post 

 them here in a day or so when I return home and consult my notebook...



 Thanks in advance. I truly appreciate all input on this matter.



 Buck



 --------

 Buck Wyndham

 RV-8 N18XL (working on fuselage &amp; systems)

 Northern Illinois





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=148988#148988

nuckolls.bob(at)cox.net
Guest

Posted: Wed Nov 28, 2007 8:43 am Post subject: Z-12 and Z-13/20 features questions

At 07:58 AM 11/28/2007 -0500, you wrote:



 	  Quote: 	
		  

<Dr.Laurence(at)mbdi.org>



Buck,



I'll put my three cents in here.



Having wired two aiplanes as per Bob's drawings, I 've

wonderd whether the E buss concept was necessary.


	


   Not if you have design goals that eliminate it . . .

   The concept of "necessary" is unique to individual

   percepti



 	  Quote: 	
		     One wiring project was  a velocity with a B&c 40 amp alt on the vacuum 

 pad, a 60  main with an E buss. It seems that the only time one will have 

 to use the E buss is 1. failure of the battery contactor (and that's 

 another issue  ) or 2. failure of both alternators. For that to happen 

 your engine is probably not running!.


	


   Yup, that's figure Z-12 . . .

 	  Quote: 	
		  If your going to use a dual alternators, split the buses and eliminate the 

E buss. Or, use a main buss and eliminate the E buss.

I'm wiring my RV9A and decided that all devices will go on the main buss.

In the event of an alt failure, pull the field breaker . . .


	




   Your alternator field power doesn't go through the

   ship's DC PWR MASTER switch?



 	  Quote: 	
		    and if necessary, turn off the battery contactor.


	


    . . . when would it be necesary? What indications

    does the pilot get and how are they interpreted

    to drive a decision to open the battery contactor?



 	  Quote: 	
		  Have a 50 to 60 amp breaker/switch from the battery plus to the main buss.


	


    ????



 	  Quote: 	
		  You become the E buss and shut down non essentail devices--It takes about 

5 to 10 seconds.

Close the breaker and you have an essential buss. It seems to me that at 

one time or another, all these instruments are "essential" to flight.


	


   The ENDURANCE-Bus is crafted for minimum power

   consumption for battery only operations. In no

   way is it intended or crafted to make any ESSENTIAL

   device unavailable to the pilot. Further, piling

   "all these instruments" into the classification

   of "essential" suggests that everything on the

   panel should have backups . . .



   I respectfully suggest that (1) with modern

   alternators and (2) artfully maintained RG

   batteries that Z-11 offers DC SYSTEM reliability

   that far exceeds that which is being flown

   in tens of thousands of TC aircraft wired

   like a 1970 C-150.



   This condition exists irrespective of

   the suite of devices installed or

   which ones are deemed "essential".

   If one does nothing other than to

   exploit what modern alternators and

   batteries have to offer, SYSTEM

   reliability is at least equal to and

   probably MUCH better than what's flying

   in most light GA aircraft toay.



   Exploiting an unused vacuum pump

   pad by plugging the hole with something

   other than a cover plate is icing on

   the cake. An SD-8 alternator offers

   ENDURANCE load support for a fist-

   full of goodies for en-route operations

   while retaining 100% of the well-

   maintained battery's capacity for

   approach to landing. An approach where EVERY

   electro-whizzie in the airplane

   is available for comfortable termination

   of flight.



   Note that all of the above makes no

   mention of numbers, kinds or

   "criticality" of any particular

   piece of equipment. Crafting that

   list (and deciding which bus to

   drive it from) is driven by anticipate

   missions to be flown, panel space and

   weight issues and the size of one's

   pocketbook.



   But in no case, does the artfully

   crafted, failure tolerant system

   deprive the pilot of any piece of

   functional equipment. Once the

   alternator(s)/battery decisions are

   are made, then it matters very little

   what architecture is adopted.



   This is where design goals should

   strive to minimize weight, parts count

   and pilot-duties for perceiving and

   reacting to RARE failures of DC

   PWR supply equipment.



   Bob . . .

nuckolls.bob(at)cox.net
Guest

Posted: Wed Nov 28, 2007 9:01 am Post subject: Z-12 and Z-13/20 features questions

 	  Quote: 	
		  

Hi Bob,



To answer your questions, I'm considering installing an SD20 because, 

frankly, a). it's available and b). I'm comfortable with a bit of 

"overkill" when it comes to electrical power generation. Cost is simply 

not an issue, and weight-saving, while important to me, is secondary to 

building a robust electrical system. (As an aside, I'm saving over 30 

pounds from a "stock" RV-8 by using a lightweight composite prop and 

lightweight aluminum landing gear. Other improvements will save even more 

weight.)



My airplane will be used for a lot of day VFR, but also some fairly 

regular IFR cross-country, and occassional night flying. It wil be 

highly-electrical dependent, with dual GRT EFIS displays, a backup Dynon 

D-10A, a Garmin 430, a Garmin SL-30, a Garmin 330 transponder, a PMA9000 

audio panel, and a Trutrak Digiflight II VSVG autopilot.  Not all of these 

items are on the E-bus, of course, but some are.



My concept of the E-bus (and I do NOT mind calling it an Essential Bus -- 

it does not scare me or exude a negative connotation -- it's what every 

sophisticated airplane I've flown in 28 years calls it) is to cover the 

loads of the aircraft's important avionics and some carefully selected 

accessories while I comfortably divert to a suitable airport where 

maintenance can be undertaken. I do not necessarily want to continue to my 

planned destination -- that goes against my personal ideas of safety. 

(That topic is a whole other thread which I do not want to get into here...)



So there you have it -- I guess I'm attracted to a 20-amp alternator 

because it exists; because installing one would allow me a margin of 

"comfortable operability" without utilizing my main battery's capacity one 

iota while I'm diverting to a suitable airport; and because cost is not 

part of the equation.



So what remains in the equation are weight, complexity (number of parts, 

wires and connectors), and reliability.



If you need to have a complete list of my E-bus loads, I'll certainly post 

them here in a day or so when I return home and consult my notebook...



Thanks in advance. I truly appreciate all input on this matter.


	


    First, I'll suggest that your system should

    be capable of continued flight to airport

    of intended destination.  Comfortable

    completion of flight with a failed piece

    of equipment is dependent upon planing

    and understanding which leads to comfortable

    decision making.



    Yes, taking the family out to McD's with

    $1,000 cash in hand assuages any concerns

    about paying for the meal, but if you have

    to traverse 30 miles of sparsely populated

    terrain and have no spare tire, then your

    cash comfort is overshadowed by your inability

    to deal with an easily anticipated and

    planned-for failure.



    I'm only suggesting that your willingness

    to pile on levels of comfort because you

    have all this extra weight carrying ability

    is 'easy' but perhaps not the best we know

    how to do. I met an RV flyer at an airshow

    some years ago with Z-14, dual EFIS (can

    fly IFR from either seat) and the guy

    said he wasn't instrument rated, didn't

    fly with instrument rated passengers but

    thought the system would improve on the

    resale price of the airplane!



    I'm only suggesting that the optimum design

    minimizes weight, parts count, cost of

    ownership and probability of pilot error

    for failure management. Take care that

    the "wad of hundreds in the wallet" don't

    lull you into a false sense of security

    while increasing overall cost of ownership

    for your airplane.



    Bob  . . .

BuckWynd

Joined: 27 Nov 2007
Posts: 10

Posted: Wed Nov 28, 2007 10:34 am Post subject: Re: Z-12 and Z-13/20 features questions

Thanks, Bob, for the information. I agree that “money does not buy happiness” and does not cover for poor design or sloppy implementation.

 

I’m back from my trip, and I’ve looked up the information on my particular requirements. 



My enroute E-Bus loads:



EFIS/MFD 1:       1.5 A

EFIS/MFD 2:       1.5 A

AHRS/Magnetometer:    0.25 A

EIS (Engine Monitor):       0.5 A

Alt Field:              1.0 A

TruTrak Autopilot head:     0.5 A

A/P servo – Roll:          1.0 A

A/P servo – Pitch:         1.0 A

Garmin 430 NAV/GPS:     1.65 A

Garmin 330:         1.0 A

Flexible map light:      0.1 A



TOTAL: 10.0



“Wow,” you say. “I see some stuff that could be moved off the bus.” Yes, you’re right. The total is 10 amps, but I could move one of the EFIS displays and the EIS off the E-bus, for a savings of 2 amps. However, the Garmin 430 draws up to 6 amps (intermittent) when transmitting, so we’re back up to 14 already. I could consider the “transmit” feature of the radio to be off-limits until I get on the ground. Airplanes can certainly be flown without transmitting on the radio. I could also delete the autopilot head and servos, and just hand-fly.



These modifications would definitely keep me below 8 amps. However, my stated goal is to be able to SAFELY and COMFORTABLY fly the airplane IFR to the nearest suitable place where repairs can be made. Coordinating my divert with ATC and getting vectors and an approach clearance are part of the “safety and comfort” clause, in my opinion. Therefore, I think that both the transponder and radio should be part of an IFR E-Bus. Similarly, an autopilot is an invaluable tool in an irregular operation such as this -- a partial electrical failure in IFR conditions.



By the way, my Dynon D-10A is not listed because it has an internal battery.



So let’s say I install a backup 7.2 Ah battery for my EFIS displays, the EIS, and the AHRS (something I’ve been contemplating doing anyway). We’re still at over 12 amps when the comm radio is transmitting. See the issue? If I want my alternator to easily handle the entire E-bus load, not share it with the main battery at all, an 8A alternator appears to be too small to handle my particular IFR panel, at least when transmitting. 



VFR is a totally different story. I can safely recover a plane VFR (or even IFR but good VMC) with a zero load on my E-Bus. It’s when we get into the clouds that an 8A alternator appears to be insufficient for my needs.



I don’t particularly want to debate what should or should not be on a person’s E-bus – that discussion could go on for years (and has). People can justify whatever makes them comfortable.



Am I wrong in thinking that I’d like to save my ENTIRE main battery for the approach and landing phase of my emergency? If so, then I have no problem with an 8A aux alternator. Somebody slap me around if I need to get off that particular train of thought.



Bob, you have recently been “talking down” the Z-13/20, but mostly without further comment – just that it “sucks.” Since you’re the guy who designed it, I’ll have to take your word for it. But before I abandon all my cool CAD drawings and start over, it would be helpful to know a bit more about why you’ve soured on it – does the design have some missing functionality, less-than-optimal reliability, or a hidden gotcha that a person should know about? Is it that you disagree with people’s design requirements and that you feel no one should have a need for more than an 8A endurance load? Is the SD20 not living up to people’s expectations somehow? I haven’t seen any of these things addressed here in this forum.



Whatever the answer is, it’s just fine with me. I have no particular attachment to any one design. I just want to get the job done: a 10+ amp E-bus, provided entirely by a standby alternator.



If the Z-12 is the answer, great.



But how about a little more information for all of us regarding the Z-13/20?



Thanks, as always, for your input!



Buck

_________________
Buck Wyndham
RV-8 N18XL (working on fuselage & systems)
Northern Illinois

nuckolls.bob(at)cox.net
Guest

Posted: Thu Nov 29, 2007 7:34 am Post subject: Z-12 and Z-13/20 features questions

At 10:34 AM 11/28/2007 -0800, you wrote:



 	  Quote: 	
		  



Thanks, Bob, for the information. I agree that “money does not buy 

happiness” and does not cover for poor design or sloppy implementation.



I’m back from my trip, and I’ve looked up the information on my 

particular requirements.



My enroute E-Bus loads:



EFIS/MFD 1       1.5 A

EFIS/MFD 2       1.5 A

AHRS/Magnetometer    0.25 A

EIS (Engine Monitor)       0.5 A

Alt Field              1.0 A

TruTrak Autopilot head     0.5 A

A/P servo – Roll          1.0 A

A/P servo – Pitch         1.0 A

Garmin 430 NAV/GPS     1.65 A

Garmin 330         1.0 A

Flexible map light      0.1 A



TOTAL: 10.0


	


   I think the solution is quite clear. Since it's your

   goal NOT to craft and exploit the operational features

   of an ENDURANCE mode of flight, I suggest that

   the SD-8 is quite adequate to your needs. This

   presumes that you plan to include and artfully maintain

   an RG battery. There's no reason not to include the

   battery's capacity in your Plan-B for expediting

   a comfortable arrival with the earth in case of

   alternator failure. Using the battery to augment

   the SD-8 by a couple of amps is a perfectly

   valid thing to consider too.



   Installing an SD20 goes more to servicing an

   endurance mode limited only by volume of fuel

   aboard.



   In any case, Z-12 or Z-14 are my best recommendations

   for incorporating the SD-20 into a robust

   architecture.



   Bob . . .

tx_jayhawk

Joined: 10 Jun 2006
Posts: 9

Posted: Fri Nov 30, 2007 8:27 pm Post subject: Re: Z-12 and Z-13/20 features questions

Hi Bob,



Could you help us all understand specifically what you do not like about the Z-13/20?  I may be slow, but I'm not sure I understand the objection at this point.



I originally went with the Z-12 in my project but switched to a Z-13 in part based on some advice you provided.  I'm wondering what may have changed in your opinion.



Thanks in advance,



Scott

BuckWynd

Joined: 27 Nov 2007
Posts: 10

Posted: Sat Dec 01, 2007 1:12 am Post subject: Re: Z-12 and Z-13/20 features questions

 	  nuckolls.bob(at)cox.net wrote: 	
		  Using the battery to augment

   the SD-8 by a couple of amps is a perfectly

   valid thing to consider too.



   Installing an SD20 goes more to servicing an

   endurance mode limited only by volume of fuel

   aboard.



   In any case, Z-12 or Z-14 are my best recommendations

   for incorporating the SD-20 into a robust

   architecture.



   Bob . . . 	




Thanks Bob. I appreciate the input, and I'll definitely keep your thoughts in mind.



It's clear that you feel the 20A alternator is not "robust" in a Z-13 architecture. I just wish I understood why. I guess I'll have to wait until AEC Edition 12 comes out...

_________________
Buck Wyndham
RV-8 N18XL (working on fuselage & systems)
Northern Illinois

nuckolls.bob(at)cox.net
Guest

Posted: Tue Dec 04, 2007 7:26 am Post subject: Z-12 and Z-13/20 features questions

At 01:12 AM 12/1/2007 -0800, you wrote:

 	  Quote: 	

nuckolls.bob(at)cox.net wrote:

 > Using the battery to augment

 >    the SD-8 by a couple of amps is a perfectly

 >    valid thing to consider too.

 >

 >    Installing an SD20 goes more to servicing an

 >    endurance mode limited only by volume of fuel

 >    aboard.

 >

 >    In any case, Z-12 or Z-14 are my best recommendations

 >    for incorporating the SD-20 into a robust

 >    architecture.

 >

 >    Bob . . .

Thanks Bob. I appreciate the input, and I'll definitely keep your thoughts 

in mind.

It's clear that you feel the 20A alternator is not "robust" in a Z-13 

architecture. I just wish I understood why. I guess I'll have to wait 

until AEC Edition 12 comes out...

   The architecture is clumsy. It will "function as advertised"

   but it's not a design I'm proud of and it tends to encourage

   folks to "overkill" on their engine driven power sources

   at the expense of $time$ and weight.

   Many folks have mistaken my lack of recommendation

   as being advice NOT to do a particular thing. When

   I say it's not something I cannot recommend, it's

   a personal judgement as to whether or not it's the

   best we know how to do . . . the elegant solution.

   I.e, it's not a design I would put on my airplane.

   When some suggestion has issues of safety,

   cost of ownership or obvious design flaws with

   respect to performance, I'll be direct in my

   suggestion that you DO NOT do this particular

   thing and explain in detail why.

   I've never told folks NOT to install off-the-shelf

   or off-the-junker alternators per anyone's lucid

   and accurate instructions. I have discouraged

   installation of barefoot IR alternators for reasons

   cited and carefully explained many times. However,

   these are demonstrably high-quality products with

   much lower risks compare to their ancestors. If

   one is willing and able to accomplish an educated

   consideration and acceptance of those risks,

   fine by me.

   My mission here is to first educate and then

   recommend based on my own recipes for success

   and sense of elegant solution. A secondary

   goal is to assist the neophyte in steering

   around perceived pot-holes. Only then will

   my advice become much more energetic than

   a recommendation.

   Bob . . .

nuckolls.bob(at)cox.net
Guest

Posted: Tue Dec 04, 2007 7:26 am Post subject: Z-12 and Z-13/20 features questions

At 08:27 PM 11/30/2007 -0800, you wrote:



 	  Quote: 	
		  



Hi Bob,



Could you help us all understand specifically what you do not like about 

the Z-13/20?  I may be slow, but I'm not sure I understand the objection 

at this point.



I originally went with the Z-12 in my project but switched to a Z-13 in 

part based on some advice you provided.  I'm wondering what may have 

changed in your opinion.


	


   See other posting. If it's already installed as

   13/20 then leave it in.



   Bob . . .

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

jpx(at)qenesis.com
Guest

Posted: Wed Dec 05, 2007 5:04 am Post subject: Z-12 and Z-13/20 features questions

 	  Quote: 	
		   From: "Robert L. Nuckolls, III" <nuckolls.bob(at)cox.net>

 Subject: Re: Re: Z-12 and Z-13/20 features questions

    The architecture is clumsy. It will "function as advertised"

    but it's not a design I'm proud of and it tends to encourage

    folks to "overkill" on their engine driven power sources

    at the expense of $time$ and weight.


	


Bob,

I believe these comments refer specifically to Z13/20, but not Z13/8 ?

Jeff Page

Dream Aircraft Tundra #10

nuckolls.bob(at)cox.net
Guest

Posted: Wed Dec 05, 2007 6:50 am Post subject: Z-12 and Z-13/20 features questions

At 07:58 AM 12/5/2007 -0500, you wrote:



 	  Quote: 	
		  



>From: "Robert L. Nuckolls, III" <nuckolls.bob(at)cox.net>

>Subject: Re: Re: Z-12 and Z-13/20 features questions

>    The architecture is clumsy. It will "function as advertised"

>    but it's not a design I'm proud of and it tends to encourage

>    folks to "overkill" on their engine driven power sources

>    at the expense of $time$ and weight.



Bob,

I believe these comments refer specifically to Z13/20, but not Z13/8 ?

Jeff Page

Dream Aircraft Tundra #10


	


   Absolutely. If I were building an airplane today,

   13/8 would be my architecture of choice. It's

   my considered opinion that 13/8 offers the

   simplest, lightest and lowest cost approach to

   system reliability.



   I think 13/20 germinated the morning after

   the night before and too many beers . . .

   or maybe it was those halbanero peppers . . .



   Bob . . .

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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