|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

06-10-2018, 01:23 PM
|
|
|
|
Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,189
|
|
and...
Then we would need to look at the switches. contactors, and relays, too.
Also would need to account for insulating the cavity that contains the turbine for heat, sound, and the potential for an unconfined turbine failure...not to mention the the separate fuel system for the turbine and preventative measures to ensure that no kerosene gets into the main tanks or gasoline into the turbine...
That's just a short list but it's enough to get started! 
__________________
Bob
Aerospace Engineer '88
RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...
Dues+ Paid 2019,...Thanks DR+
|

06-18-2018, 02:44 PM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
The NTSB published a final report on the SQ-12 engine power loss:
https://app.ntsb.gov/pdfgenerator/Re...Final&IType=LA
Short version: All the injectors on one circuit breaker.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
|

06-18-2018, 03:17 PM
|
|
|
|
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
|
|
Well, duhhh.
It would be amusing to think about all those guys who poo poo alternative engines, and then throw something like that, with such obviously un-thought-out design work, on a 'traditional' engine and call it good. But for how scary it is...
Charlie
|

06-18-2018, 04:42 PM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
Let's treat the information in the spirit of aviation safety culture...lessons to be learned, "There but for the grace of God", etc.
Too often, "duh" is only obvious in retrospect.
The docket should be interesting, when available.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Last edited by DanH : 06-18-2018 at 04:48 PM.
|

06-18-2018, 06:08 PM
|
 |
|
|
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
|
|
5 amp ok for each injector. Not ok for for all 4.
|

06-18-2018, 07:23 PM
|
|
|
|
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
|
|
Dan,
From the installation manual, here are all the instructions I could find for power to the system:
11. Ignition power (these wires stay bundled and fed from a separate IGNITION breaker).
12. ECU power (black to ground bus, red to 5A ECU PWR breaker).
The closest thing I could find to a wiring diagram is a photo of the harness.
|

06-18-2018, 09:32 PM
|
|
|
|
Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,189
|
|
more...
If you are speaking about the EFII system, in the ignition install manual, right below the photo of the harness is this quote:
"...
The Ignition Power wires provide +12V power to the ignition coils. Provide +12V power to these wires through a single 10A circuit breaker.
The red ECU power wire needs to be connected to a source or +12V through a 5A circuit breaker. The black ECU power wire should be connected to your ground bus using a reliable crimped or soldered connection method..."
In the EFII install manual, this quote also appears:
"...The single ECU EFII systems require three +12V circuits and associated circuit breakers. The dual ECU systems require an extra breaker for the second ECU. If you plan on using an EFII Bus Manager, you may also need panel space for a Fuel Pump Mode Switch, and Start Battery Select
Switch. The circuit breaker requirements for below:
System ECU breaker(s)
EFII-4 5A
EFII-4R 5A (x2)
EFII-6 5A
EFII-6R 5A (x2)
the different versions of the EFII system are listed
Ignition breaker
10A 10A 10A 10A 15A 10A 15A 10A..."
The table format did not paste properly but all the info is there in the install manuals, if you care to check it out...
__________________
Bob
Aerospace Engineer '88
RV-10
Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful
Wiring...
Dues+ Paid 2019,...Thanks DR+
|

06-18-2018, 10:08 PM
|
|
|
|
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
|
|
I think you're looking at the *ignition* manual; not the full ignition/injection controller manual (subject of discussion).
I guess I should have included the link.
https://www.flyefii.com/media/EFII_I...al_rev9-13.pdf
And I don't see a proper wiring diagram, in either manual. I did find the text below, under 'grounding the vehicle systems'. (?)
"The single ECU EFII systems require three +12V circuits and associated circuit breakers. The
dual ECU systems require an extra breaker for the second ECU. If you plan on using an EFII Bus
Manager, you may also need panel space for a Fuel Pump Mode Switch, and Start Battery Select
Switch. The circuit breaker requirements for the different versions of the EFII system are listed
below:
System ECU breaker(s) Ignition breaker Fuel Pump breaker
EFII-4 5A 10A 10A
EFII-4R 5A (x2) 10A 10A
EFII-6 5A 15A 10A
EFII-6R 5A (x2) 15A 10A "
No indication of where the injectors get their power; it mentions breakers for ECU, Ignition, and fuel pump.
|

06-19-2018, 06:11 AM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
Docket items:
https://dms.ntsb.gov/public/61000-61...262/615998.pdf
https://dms.ntsb.gov/public/61000-61...262/615999.pdf
https://dms.ntsb.gov/public/61000-61...262/616000.pdf
https://dms.ntsb.gov/public/61000-61...262/616002.pdf
Speaking strictly about injector power, there are many lessons.
The investigation tends to focus on an obvious proximate cause, an undersized breaker. In this accident, the instrument panel vendor installed a single 5A breaker for injector power supply based on what may have been an offhand comment from the EFI vendor. That recommendation was accepted or overlooked by the owner/builder, the builder assistance crew, and the engine vendor, who helped with the installation. The lesson? Like everything else, final responsibility rests with the builder.... trust but verify. When in doubt, measure the operating current draw, size the supply wire for a reasonable margin, then size the breaker to protect the wire.
Don't be fooled by average current. Depending on the device, there may be a peak current followed by zero current (here, the typical injector), or a short inrush when first flicked on (the typical incandescent light), or a higher than normal current when under a temporary heavy load (like a DC motor). The lesson? Understand the device you're wiring.
A single circuit breaker to drive the coils and the four injectors is an extension of the "single crankshaft nut" philosophy. What it ignores is that if any one of the six component feeds (two coils, four injectors) becomes shorted to ground, all six components go offline. In this case someone wanted to separate the injector power from the coil power. Since that doesn't improve reliability, we can only conclude that again, it was a decision based on hubris rather than analysis. This contrasts with using six individual circuit protection devices, so that if any one is shorted, the other five remain functional. Most RV's will fly just fine on a single ignition, or with an injector loss, i.e. with one dead cylinder. The lesson? Subject every part of the wiring to a basic "short or open" analysis, as discussed elsewhere. Ignore the probability of a short or open, but rather, understand what happens if it does short or open.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Last edited by DanH : 06-19-2018 at 07:42 AM.
|

06-19-2018, 08:51 PM
|
 |
|
|
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
|
|
There was a fatal accident with our EFI installed on an Egg 6 engine a number of years back, which I helped the TSB up here investigate since they were unfamiliar with these engines or EFI. After going over the obvious, I found the cause in about 15 minutes for the power loss. Injector power was mis-wired to the wrong breaker value (adjacent breaker). In this case a 3 amp one.
It did not show up in extensive ground running as the rpms did not get quite as high as they did with the prop unloaded a bit in flight (current draw a bit higher at higher rpms). Engine stopped at about 300 feet after takeoff and a landing was attempted on the crossing runway. Stall/spin and my friend test flying, was killed.
As Dan said, this is vitally important stuff.
For Vertical Power users, please read our warnings about setting breakers values on these devices when using our EFI.
Last edited by rv6ejguy : 06-19-2018 at 08:55 PM.
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 12:12 AM.
|