VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #91  
Old 05-17-2018, 07:29 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,792
Default

Quote:
Originally Posted by DanH View Post
True enough. For now we can only hope some EFI vendor will eventually automate the injector ECU swap.
I can only say that after months of work on the CPI-2 to automate switching from one power source to another and the dozens of associated problems and added components, pilot intervention may be a better solution.

Fully 3/4 of the CPI-2 development time has been soaked up trying to do this seemingly simple task. Now if we have to write more code to detect failures of the primary ECU and decide how, if and when we should switch over to the backup, we've added yet more complexity. The benefits become questionable.

I'm not saying we won't go there with the EM-6 since we may be able to apply a lot of the solutions and circuits developed on the CPI-2 but we'll be taking a long hard look at it first.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 424.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 05-17-2018 at 07:31 AM.
Reply With Quote
  #92  
Old 05-17-2018, 08:11 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,792
Default Switches

Here is the link for the Honeywell Mil Spec switches kindly provided by Les Kearney who is installing our EFI on his RV-10 just down the street:

https://sensing.honeywell.com/honeyw...05430-3-en.pdf
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 424.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


Reply With Quote
  #93  
Old 05-17-2018, 10:19 AM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 7,918
Default

Quote:
Originally Posted by rv6ejguy View Post
I'm not saying we won't go there with the EM-6....
In the meantime, it sure would be nice to see a complete wiring diagram for a dual EM-5. This one seems to be missing all the details for injector switching:

http://www.sdsefi.com/dualecu4.pdf

John Bright's notes state that injector switching is different for SDS and EFII installations. Robert doesn't seem to have published a diagram for his version of the EM, or for the System 32. Apparently Mr. Relentless didn't know the secret handshake when he installed the ACE 409 in the SQ12, as Robert says it got parked hard due to "non-standard wiring" (post #70).

So what was (or is) "standard", and how are they different?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #94  
Old 05-17-2018, 10:34 AM
unitink72 unitink72 is offline
 
Join Date: Oct 2014
Location: Cedar Rapids, IA
Posts: 156
Default

Quote:
Originally Posted by Pukauma View Post
So I include my latest electrical power architecture scheme. My goal is to be as SIMPLE as possible, with the least number of switches/relays/components. Not a lot of detail here, just concept.
Unfortunately this thread took a 3-page detour. Glad we're getting back to original intent. I'll take a stab at your diagram.

First of all, will you have regulators that you can adjust? I plan to do the B&C ones in mine, even though hopefully the main alt will be off-the-autozone-shelf externally regulated. With these you can reduce the diodes and have overvoltage protection.

I don't think you need two switches to feed the engine bus. I don't feel the need to mitigate the case where two battery contactors fail on a flight. That probability has to be astronomical. So why not feed one of the Engine bus leads right off the contactor?

Here's my design, mostly stolen from Zuldarin. Just a thought experiment so far, but have been thinking about it for some time:

__________________
Josh T
RV-10 #1750
N67SC reserved
http://n67sc.blogspot.com/
2018 Dues Paid
Reply With Quote
  #95  
Old 05-17-2018, 12:14 PM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 1,913
Default For the record:

Quote:
Originally Posted by Mike S View Post
Although this was originally in reference to automobile racing-----it is often quoted in things aeronautical ........and rightly so.

This quote, well, almost, was originally from Ed Heinemann of Douglas Aircraft.
It was said during a prelinary design review for the Douglas A4D. The actual quote was, "simplicate, and add lightness"
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 515 in 9 years (would have flown more this year if not for fire smoke)
also LS-6-15/18 sailplane
VAF donation Dec 2017
Reply With Quote
  #96  
Old 05-17-2018, 01:02 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,792
Default

Quote:
Originally Posted by DanH View Post
In the meantime, it sure would be nice to see a complete wiring diagram for a dual EM-5. This one seems to be missing all the details for injector switching:

http://www.sdsefi.com/dualecu4.pdf

John Bright's notes state that injector switching is different for SDS and EFII installations. Robert doesn't seem to have published a diagram for his version of the EM, or for the System 32. Apparently Mr. Relentless didn't know the secret handshake when he installed the ACE 409 in the SQ12, as Robert says it got parked hard due to "non-standard wiring" (post #70).

So what was (or is) "standard", and how are they different?
I didn't draw the details in for the injector relay switching as they are not germane to the basic power/ ground layout which is what this drawing is attempting to easily convey. It would just clutter up the schematic.

Injectors are ground switched through the ECU so only +12V connections are shown. Both ECUs are always active on the 4 cylinder setups, one running each set of 4 spark plugs. The primary ECU normally drives the 4 injectors. The relays just switch injector driving tasks over to backup when you throw the switch. The backup ECU only has essential sensors tied to it- Hall and MAP, no temps or TPS because they're not needed to keep the engine running.

6 cylinder dual ECU setups are quite different from the 4 cylinder ones.

I also don't show all the sensors or charging wiring either for the same reason.

We supply the ECU end of all the wiring completed, built to each customer's length and termination specs. Your task is basically down to connecting the red power and black ground wires provided and crimping the sensor pins once you pull the harnesses through the firewall grommet.

I have no knowledge of how the rebranded dual ECU setups were wired.

With any layout, we feel you must have a way to isolate the essential bus from each battery and alternator because if those go bad in some way you can take down the ECUs.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 424.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 05-22-2018 at 09:15 AM.
Reply With Quote
  #97  
Old 05-17-2018, 03:31 PM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 7,918
Default

Quote:
Originally Posted by Pukauma View Post
My goal is to be as SIMPLE as possible, with the least number of switches/relays/components...

This also stays in line with emergency procedures, as in masters off will not kill the engine.
Conceptually excellent.

Quote:
Originally Posted by rv6ejguy View Post
It would just clutter up the schematic.
The avionics standard is a professional pinout drawing, regardless of who assembles the harness. Why should EFI be different?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #98  
Old 05-17-2018, 04:58 PM
Pukauma Pukauma is offline
 
Join Date: Jul 2014
Location: West Covina, Ca
Posts: 51
Default

In response to:

Unitink72:
"First of all, will you have regulators that you can adjust?"

Yes, BandC also.

"I don't think you need two switches to feed the engine bus."
I would defer to the post from Ross at SDS......."With any layout, we feel you must have a way to isolate the essential bus from each battery and alternator because if those go bad in some way you can take down the ECUs."

Mike S:
"I used a switch rated at 20A, double pole and tied the two sides together----In theory this will double the load capacity of the switch."
I did some research on this. It seems that 99.9% of the time, one of the contacts will close first, carrying the full load. Kind of negates doubling them up. So I am looking for a 30A switch. Nevertheless, glad it is working for you, and creative thinking.

"In your diagram is one of the busses carrying essential loads like nav or com equipment? If so, you could tie the two busses together with a diode to provide power from either battery automatically, should one power source take a little nap."
I am considering this, but not sure if I want to tie the two together if not necessary. Diodes can fail either open or closed. Open would then negate it's benefit. And if closed could transfer problem from one bus to another. Just not sure of the benefit/potential risk yet.

I am also not sure about a bus-tie for the same rational. It could transfer overvoltages or issues to the other bus before it is recognized.

I did find this 30A switch. Could not find any locking switch rated at 30A. Any negative opinions? https://www.gamainc.com/product/28a-mtd/

Lastly, thank you for all the responses and help. I could not do this project without all the input.
__________________
Cliff Langlois
West Covina, CA
Cliffsrv10.blogspot.com

Project Sold 9/2018
RV-10
Empennage finished!
QB Fuselage and wings in hand
Taking a bite of the elephant every day.
Dues paid-grateful

Last edited by Mike S : 05-17-2018 at 06:52 PM.
Reply With Quote
  #99  
Old 05-17-2018, 05:17 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,792
Default

Quote:
Originally Posted by DanH View Post
Conceptually excellent.



The avionics standard is a professional pinout drawing, regardless of who assembles the harness. Why should EFI be different?
If we do a single schematic with every wire and pin shown it would be very hard to follow the basic concepts being discussed in this thread. We prefer to have separate drawings to more clearly illustrate each section. This is simply an overview of the basic power and ground connections, switches and breakers.

Lots of people's eyes glaze over when you have 150 connections shown on one frame.

Cliff's graphic is clearly understood by almost anyone because it's dirt simple. I'll put the question out there though- what are the diodes really doing for you though with the isolation switches on each bus feed, assuming you have only one source at a time connected to the bus, current can only flow one way. I'm thinking they could be ditched too. I've seen diodes fail both shorted and open a number of times over the years.

This thread is starting to drill down to just the essentials required to keep the electronics running with maximum reliability. It's good to see different ideas and evaluate their validity. I just gave this thread 4 stars here. Lots of useful discussion this week.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 424.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 05-17-2018 at 05:43 PM.
Reply With Quote
  #100  
Old 05-17-2018, 05:27 PM
rv7charlie rv7charlie is online now
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,143
Default

Quote:
Originally Posted by Pukauma View Post
"I don't think you need two switches to feed the engine bus."
I would defer to the post from Ross at SDS......."With any layout, we feel you must have a way to isolate the essential bus from each battery and alternator because if those go bad in some way you can take down the ECUs."

Mike S:
"I used a switch rated at 20A, double pole and tied the two sides together----In theory this will double the load capacity of the switch."
I did some research on this. It seems that 99.9% of the time, one of the contacts will close first, carrying the full load. Kind of negates doubling them up. So I am looking for a 30A switch. Nevertheless, glad it is working for you, and creative thinking.

"In your diagram is one of the busses carrying essential loads like nav or com equipment? If so, you could tie the two busses together with a diode to provide power from either battery automatically, should one power source take a little nap."
I am considering this, but not sure if I want to tie the two together if not necessary. Diodes can fail either open or closed. Open would then negate it's benefit. And if closed could transfer problem from one bus to another. Just not sure of the benefit/potential risk yet.

I am also not sure about a bus-tie for the same rational. It could transfer overvoltages or issues to the other bus before it is recognized.


Lastly, thank you for all the responses and help. I could not do this project without all the input.
Overvoltage issues should be handled by system(s) independent of bus switching. The B&C regulators should handle that.

I found some of these on ebay:
http://www.elecdirect.com/truck-trai...oggle-switches
The handle is a bit oversized, which you might be able to convince yourself is a good thing (differently shaped switches can help ergonomics).

I'm using one to directly switch my engine bus (auto style efi), and another (different area of the panel) as a bus tie switch. I have the luxury of two identical alternators (alt engine), so I have only engine and avionics buses; no need for load shedding. The avionics bus is switched by a standard master contactor, and starting is handled through the avionics bus.

Charlie

Last edited by Mike S : 05-17-2018 at 06:52 PM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 09:57 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.