 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
mark.supinski(at)gmail.co
Guest
|
 Posted: Fri Jul 03, 2009 7:58 pm Post subject: Switch wiring conundrum |
 |
|
Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI injectors using a single 2-XX switch. I can't find a way to do what I want to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I have a single 3 position switch (Primary - Both - Secondary). That part is easy enough using a 2-10. Here's the added trick: whenever Both is not selected, I need to tie a certain line on the EFI to ground. (This lets the EFI know one bank is offline & it automatically doubles the fuel flow through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each bank to a 2-3. One side of 2-3 control whether the bank gets power, the other side controls whether the EFI line ties to ground. When an injector bank has failed, the pilot is "guessing" which bank to take offline. If he guesses right, the engine smooths out & all is well for a no-sweat landing. If he guesses wrong, the engine runs off & he must quickly restore power to the bank he just turned off & remove power from the "other" bank. Using two separate switches for this seems like a recipe for frantically flipping switches to try to get the engine back on if the pilot guesses wrong. My idea is that if it is a single pri-both-sec switch, it is much easier to simply reverse the position of the single switch you already have a hold of should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do this without requiring 2 switches! Or, at least I can find out it is impossible & I can resign myself to having two switches.
Thanks,
Mark
[quote][b]
| | - 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 |
|
|
|
| Back to top |
|
 |
bob(at)bob-white.com
Guest
|
| Posted: Fri Jul 03, 2009 8:52 pm Post subject: Switch wiring conundrum |
|
|
Hi Mark,
There isn't as much of a problem with the two switch solution as you
are imagining. When you turn off one bank and the engine doesn't run
better, you already have your hand on that switch and can immediately
turn it back on. Then just turn off the second switch (which is
probably, or should be, right next to it).
Bob W.
On Fri, 3 Jul 2009 21:55:14 -0600
"Mark R. Supinski" <mark.supinski(at)gmail.com> wrote:
| Quote: | Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI
injectors using a single 2-XX switch. I can't find a way to do what I want
to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I
have a single 3 position switch (Primary - Both - Secondary). That part is
easy enough using a 2-10. Here's the added trick: whenever Both is not
selected, I need to tie a certain line on the EFI to ground. (This lets the
EFI know one bank is offline & it automatically doubles the fuel flow
through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each bank
to a 2-3. One side of 2-3 control whether the bank gets power, the other
side controls whether the EFI line ties to ground. When an injector bank
has failed, the pilot is "guessing" which bank to take offline. If he
guesses right, the engine smooths out & all is well for a no-sweat landing.
If he guesses wrong, the engine runs off & he must quickly restore power to
the bank he just turned off & remove power from the "other" bank. Using two
separate switches for this seems like a recipe for frantically flipping
switches to try to get the engine back on if the pilot guesses wrong. My
idea is that if it is a single pri-both-sec switch, it is much easier to
simply reverse the position of the single switch you already have a hold of
should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do this
without requiring 2 switches! Or, at least I can find out it is impossible
& I can resign myself to having two switches.
Thanks,
Mark
|
--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://roblinstores.com/
| | - 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 |
|
|
|
| Back to top |
|
|
mrspudandcompany(at)veriz
Guest
|
| Posted: Sat Jul 04, 2009 4:45 am Post subject: Switch wiring conundrum |
|
|
[quote]
Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI injectors using a single 2-XX switch. I can't find a way to do what I want to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I have a single 3 position switch (Primary - Both - Secondary). That part is easy enough using a 2-10. Here's the added trick: whenever Both is not selected, I need to tie a certain line on the EFI to ground. (This lets the EFI know one bank is offline & it automatically doubles the fuel flow through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each bank to a 2-3. One side of 2-3 control whether the bank gets power, the other side controls whether the EFI line ties to ground. When an injector bank has failed, the pilot is "guessing" which bank to take offline. If he guesses right, the engine smooths out & all is well for a no-sweat landing. If he guesses wrong, the engine runs off & he must quickly restore power to the bank he just turned off & remove power from the "other" bank. Using two separate switches for this seems like a recipe for frantically flipping switches to try to get the engine back on if the pilot guesses wrong. My idea is that if it is a single pri-both-sec switch, it is much easier to simply reverse the position of the single switch you already have a hold of should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do this without requiring 2 switches! Or, at least I can find out it is impossible & I can resign myself to having two switches.
Thanks,
Mark
I think you are overlooking an important point. With one switch you have a "single point of failure", which cauld kill both EFI's simultaneously. My preference/recommendation is TWO switches.
Roger
[b]
| | - 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 |
|
|
|
| Back to top |
|
|
klehman(at)albedo.net
Guest
|
| Posted: Sat Jul 04, 2009 4:45 am Post subject: Switch wiring conundrum |
|
|
My first thought would be to use a transistor or NAND gate chip to
reverse the logic of the on signal.
Second thought is that you may not want to flick switches in a hurry. I
run independent systems and it does take a second to fill the second
fuel rail if I don't prime it first. By that I mean the second fuel rail
seems to get the fuel very slowly sucked out of it during cruise.
Third thought is that I would not use a single switch point of failure
for both injectors anyway. Note that it is no big deal if the engine
gets double the required fuel for a short period. It will still run and
make power during that time. Another option is to use a mechanical bar
arranged to mechanically operate two or more switches simultaneously.
Ken
Mark R. Supinski wrote:
| Quote: | Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI
injectors using a single 2-XX switch. I can't find a way to do what I
want to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I
have a single 3 position switch (Primary - Both - Secondary). That part
is easy enough using a 2-10. Here's the added trick: whenever Both is
not selected, I need to tie a certain line on the EFI to ground. (This
lets the EFI know one bank is offline & it automatically doubles the
fuel flow through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each
bank to a 2-3. One side of 2-3 control whether the bank gets power, the
other side controls whether the EFI line ties to ground. When an
injector bank has failed, the pilot is "guessing" which bank to take
offline. If he guesses right, the engine smooths out & all is well for
a no-sweat landing. If he guesses wrong, the engine runs off & he must
quickly restore power to the bank he just turned off & remove power from
the "other" bank. Using two separate switches for this seems like a
recipe for frantically flipping switches to try to get the engine back
on if the pilot guesses wrong. My idea is that if it is a single
pri-both-sec switch, it is much easier to simply reverse the position of
the single switch you already have a hold of should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do
this without requiring 2 switches! Or, at least I can find out it is
impossible & I can resign myself to having two switches.
Thanks,
Mark
|
| | - 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 |
|
|
|
| Back to top |
|
|
mark.supinski(at)gmail.co
Guest
|
| Posted: Sat Jul 04, 2009 7:54 am Post subject: Switch wiring conundrum |
|
|
Well, that's certainly something to stew on.
I wish I had better information on what the failure modes for these injectors really were. For instance -- do injectors fail open or fail closed? Wiring in the switching is optional in the manual - implying I could happily go flying with no ability to disable injector banks in flight. I truly do not have room for two switches without making radical changes. I think I have to go stare at the drawings and the physical panel some more & either come to terms with no switches or two switches...
Thanks all-
Mark
On Sat, Jul 4, 2009 at 6:43 AM, Roger <mrspudandcompany(at)verizon.net (mrspudandcompany(at)verizon.net)> wrote:
[quote]
| Quote: |
Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI injectors using a single 2-XX switch. I can't find a way to do what I want to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I have a single 3 position switch (Primary - Both - Secondary). That part is easy enough using a 2-10. Here's the added trick: whenever Both is not selected, I need to tie a certain line on the EFI to ground. (This lets the EFI know one bank is offline & it automatically doubles the fuel flow through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each bank to a 2-3. One side of 2-3 control whether the bank gets power, the other side controls whether the EFI line ties to ground. When an injector bank has failed, the pilot is "guessing" which bank to take offline. If he guesses right, the engine smooths out & all is well for a no-sweat landing. If he guesses wrong, the engine runs off & he must quickly restore power to the bank he just turned off & remove power from the "other" bank. Using two separate switches for this seems like a recipe for frantically flipping switches to try to get the engine back on if the pilot guesses wrong. My idea is that if it is a single pri-both-sec switch, it is much easier to simply reverse the position of the single switch you already have a hold of should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do this without requiring 2 switches! Or, at least I can find out it is impossible & I can resign myself to having two switches.
Thanks,
Mark
I think you are overlooking an important point. With one switch you have a "single point of failure", which cauld kill both EFI's simultaneously. My preference/recommendation is TWO switches.
Roger
|
| Quote: |
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
[b]
| | - 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 |
|
|
|
| Back to top |
|
|
Sam
Joined: 18 May 2008
Posts: 135
|
| Posted: Sat Jul 04, 2009 12:06 pm Post subject: Switch wiring conundrum |
|
|
Mark - FWIW, I went through this same conundrum earlier this year. I finally grasped the fact that two switches would be the most reliable.
Sam
www.samhoskins.blogspot.com
On Sat, Jul 4, 2009 at 10:52 AM, Mark R. Supinski <mark.supinski(at)gmail.com (mark.supinski(at)gmail.com)> wrote:
[quote] Well, that's certainly something to stew on.
I wish I had better information on what the failure modes for these injectors really were. For instance -- do injectors fail open or fail closed? Wiring in the switching is optional in the manual - implying I could happily go flying with no ability to disable injector banks in flight. I truly do not have room for two switches without making radical changes. I think I have to go stare at the drawings and the physical panel some more & either come to terms with no switches or two switches...
Thanks all-
Mark
On Sat, Jul 4, 2009 at 6:43 AM, Roger <mrspudandcompany(at)verizon.net (mrspudandcompany(at)verizon.net)> wrote:
| Quote: |
| Quote: |
Hello everyone-
I've been wracking my brain trying to figure out a way to control my EFI injectors using a single 2-XX switch. I can't find a way to do what I want to do (perhaps there is no way).
Here's what I'm trying to accomplish:
I have 2 banks of injectors. I need to be able to wire them such that I have a single 3 position switch (Primary - Both - Secondary). That part is easy enough using a 2-10. Here's the added trick: whenever Both is not selected, I need to tie a certain line on the EFI to ground. (This lets the EFI know one bank is offline & it automatically doubles the fuel flow through the remaining bank.)
The suggested implementation from the EFI manufacturer is to wire each bank to a 2-3. One side of 2-3 control whether the bank gets power, the other side controls whether the EFI line ties to ground. When an injector bank has failed, the pilot is "guessing" which bank to take offline. If he guesses right, the engine smooths out & all is well for a no-sweat landing. If he guesses wrong, the engine runs off & he must quickly restore power to the bank he just turned off & remove power from the "other" bank. Using two separate switches for this seems like a recipe for frantically flipping switches to try to get the engine back on if the pilot guesses wrong. My idea is that if it is a single pri-both-sec switch, it is much easier to simply reverse the position of the single switch you already have a hold of should the guess be wrong.
Hopefully someone is cleverer than I am and can figure out how to do this without requiring 2 switches! Or, at least I can find out it is impossible & I can resign myself to having two switches.
Thanks,
Mark
I think you are overlooking an important point. With one switch you have a "single point of failure", which cauld kill both EFI's simultaneously. My preference/recommendation is TWO switches.
Roger
|
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
a>http://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
[b]
| | - 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 |
|
_________________
Sam Hoskins
www.samhoskins.blogspot.com |
|
| Back to top |
|
|
klehman(at)albedo.net
Guest
|
| Posted: Sat Jul 04, 2009 6:09 pm Post subject: Switch wiring conundrum |
|
|
FWIW here is my opinion on electronic injectors:
The most likely failure mode is low flow due clogging or zero flow due
to a wiring fault. Clogging/leaking risk is likely raised on some
aircraft due to using filters that are not as fine as in automobiles.
Coil failure resulting in no flow or continuous (stuck on) flow is rare
but both have been known to occur I'm told. I consider a stuck on
injector or a leaking injector to have no serious consequence for
aviation other than a rough idle after landing. And of coarse some fire
risk when on the ground or at idle.
ie. the major risk is a wiring problem or blown fuse/relay caused by a
wiring problem.
Ken
Mark R. Supinski wrote:
| Quote: | Well, that's certainly something to stew on.
I wish I had better information on what the failure modes for these
injectors really were. For instance -- do injectors fail open or fail
closed?
|
| | - 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 |
|
|
|
| Back to top |
|
|
mark.supinski(at)gmail.co
Guest
|
| Posted: Sat Jul 04, 2009 8:27 pm Post subject: Switch wiring conundrum |
|
|
Thanks to everyone for their thoughts.
I "bit the bullet" and celebrated the 4th of July by spending a delightful 5 hours under my instrument panel moving components / rewiring / etc to shoe-horn in room for another switch -- which got in there with 0.05" to spare. God then smiled on me & miraculously there were even two new 2-3 switches squirreled away in the back of the tool chest to allow me to directly replace the old 2-10.
Mark
On Sat, Jul 4, 2009 at 8:05 PM, Ken <klehman(at)albedo.net (klehman(at)albedo.net)> wrote:
[quote] --> AeroElectric-List message posted by: Ken <klehman(at)albedo.net (klehman(at)albedo.net)>
FWIW here is my opinion on electronic injectors:
The most likely failure mode is low flow due clogging or zero flow due to a wiring fault. Clogging/leaking risk is likely raised on some aircraft due to using filters that are not as fine as in automobiles.
Coil failure resulting in no flow or continuous (stuck on) flow is rare but both have been known to occur I'm told. I consider a stuck on injector or a leaking injector to have no serious consequence for aviation other than a rough idle after landing. And of coarse some fire risk when on the ground or at idle.
ie. the major risk is a wiring problem or blown fuse/relay caused by a wiring problem.
Ken
Mark R. Supinski wrote:
| Quote: | Well, that's certainly something to stew on.
I wish I had better information on what the failure modes for these injectors really were. For instance -- do injectors fail open or fail closed?
|
===========
-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
===========
http://forums.matronics.com
===========
le, List Admin.
="_blank">http://www.matronics.com/contribution
===========
[b]
| | - 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 |
|
|
|
| Back to top |
|
|
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Thu Jul 09, 2009 6:20 am Post subject: Switch wiring conundrum |
|
|
At 11:25 PM 7/4/2009, you wrote:
| Quote: | Thanks to everyone for their thoughts.
I "bit the bullet" and celebrated the 4th of July by spending a
delightful 5 hours under my instrument panel moving components /
rewiring / etc to shoe-horn in room for another switch -- which got
in there with 0.05" to spare. God then smiled on me & miraculously
there were even two new 2-3 switches squirreled away in the back of
the tool chest to allow me to directly replace the old 2-10.
|
I think this is a good move my friend. In about a year,
I'll be able to share the unfortunate details on an electrical
system wherein the system designer took ingredients for
biscuits, bread, hot cereal, and dumplings and
stirred them into a new product that turned out to
be less than palatable . . . and was in fact
hazardous to health.
It's in our best interests to first consider the
manufacturer's instructions for integrating any critical
components into an airplane. But it does not automatically
follow that the manufacturer of a product is well versed
in the art of failure mode effects analysis and design
for failure tolerance. We should strive for the lightest,
least expensive and least numbers of parts that minimize
the need for pilot attention and intervention. I.e. the
elegant solution. EVERY design is fair game for critical
review.
There's no such thing as a SAFE airplane, automobile,
handgun or skateboard. There are considerations of design,
installation, operation and environment that always yield
to logical incorporation of simple-ideas into minimum risk
recipes for success.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
| | - 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 |
|
|
|
| Back to top |
|
|
|
|
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
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
