Matronics Email Lists :: View topic - Philosophy of Design

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Philosophy of Design - Endurance Bus

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

dale.r(at)cox.net
Guest

Posted: Mon Dec 22, 2008 8:59 am Post subject: Philosophy of Design - Endurance Bus

Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   ...

    I presume you're talking about the alternate feed path

    to the e-bus. What is the value in putting a breaker on

    the panel for this function as opposed to a switch? Do you

    plan to pre-flight check this path?  Is there also wire

    protection on this path located right at the battery

    bus?


	


Bob,



   There are apparently some elements of the concept that I

don't have a good handle on yet.  Forgive me if it is already

covered in AEC; but that's a big volume and I'm actually

jumping a bit ahead in my build, so that I can do some of the

ground-work while it's still convenient to do them in an

early stage of the fuselage construction.



   I'm building a glass pusher (COZY) with an "alternative"

engine.  No mags.



   To my understanding - so far - the "endurance" bus has only

the things on it that I ~must~ have to conclude my flight

safely - albeit possibly truncated - in the event that my

alternator fails. So, I'm having a problem understanding why

one would want to switch access to that bus.  To connect to

a back-up supply of electrons?



   I'm planning to connect the bus supporting my bare

essentials directly to the battery, then run a switched/fused

connection to my "everything else" bus from that.  To

accomplish that, I'm running a "0" cable from the B+

terminal to my starter solenoid (about 18") and then a pair

of #6 welding cables (+ & -) to the front of the airplane, and

another #10 wire to the ECU which, at present, is only a few

inches from the battery.



   Am I overlooking something important?



Dale R.

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 22, 2008 12:08 pm Post subject: Philosophy of Design - Endurance Bus

At 10:56 AM 12/22/2008, you wrote:

 	  Quote: 	
		  



Robert L. Nuckolls, III wrote:

>...

>    I presume you're talking about the alternate feed path

>    to the e-bus. What is the value in putting a breaker on

>    the panel for this function as opposed to a switch? Do you

>    plan to pre-flight check this path?  Is there also wire

>    protection on this path located right at the battery

>    bus?



Bob,



   There are apparently some elements of the concept that I

don't have a good handle on yet.  Forgive me if it is already

covered in AEC; but that's a big volume and I'm actually

jumping a bit ahead in my build, so that I can do some of the

ground-work while it's still convenient to do them in an

early stage of the fuselage construction.



   I'm building a glass pusher (COZY) with an "alternative"

engine.  No mags.



   To my understanding - so far - the "endurance" bus has only

the things on it that I ~must~ have to conclude my flight

safely - albeit possibly truncated - in the event that my

alternator fails. So, I'm having a problem understanding why

one would want to switch access to that bus.  To connect to

a back-up supply of electrons?


	


   Not necessarily. The original concept for an E-bus

   was to support devices useful for en-route flight

   ops for the purpose of (1) bypassing the battery contactor

   and eliminating its parasitic (no value added) load and

   (2) powering up goodies useful for confident continued flight

   until airport of destination is in sight.

 	  Quote: 	
		     I'm planning to connect the bus supporting my bare

essentials directly to the battery, then run a switched/fused

connection to my "everything else" bus from that.  To

accomplish that, I'm running a "0" cable from the B+

terminal to my starter solenoid (about 18") and then a pair

of #6 welding cables (+ & -) to the front of the airplane, and

another #10 wire to the ECU which, at present, is only a few

inches from the battery.



   Am I overlooking something important?


	


   Dunno . . . the z-figures architectures are finely

   sorted for the purpose of minimizing failure modes,

   keeping transition from plan-a to plan-b. The grand

   notion was that loss of an alternator should not

   automatically turn into an emergency with an immediate

   landing on foreign tarmac. The premise of the e-bus

   stood on a 3-legged "stool" that says (a) equipment

   needed for x-hours of en-route flight can be exceedingly

   low energy, (b) it's easy to KNOW how long the ship's

   battery will support this energy requirement and (c)

   once you're cleared to land, the concrete ahead belongs

   to you and turning the master switch back ON to support

   more goodies adds no potential for hazard to the flight

   even if the battery folds before you get the wheels on

   the ground.



   Adding the SD-8 allows one to increase endurance loads

   up to and perhaps a bit over the ability of the SD-8

   to deliver . . . while keeping the battery mostly (if

   not totally) reserved for descent and approach to landing.



   If shuffling the busses and re-sorting items feed by

   those accommodates alternative design goals,

   by all means. Just be aware not all changes are "golden"

   and may introduce failure mode effects that demand

   a new understanding on the part of the pilot.



   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum