Hi
Mike,
Was not trying to get
you to change your wiring, just providing my viewpoint on my preference.
As I said - having the switches brings some down side such as possible component
failure (switches), miswiring causing trouble shooting and head scratching,
etc.
Yes, I once had an
injector fail to open (turned out to have developed an open coil) in
flight – at the time of flight was not certain what the problem was but found
that by switching off the affected pair made the engine run smoother and EGT
even out. Could undoubtedly have made it home without doing that in this
case, but it was nice to isolate the problem and come home with a smooth running
engine.
Early on I discovered
that some of the injectors I was trying out on the ground – were bad (coil OK
with Ohm meter check) but just wouldn’t inject fuel, the switches make it much
easier to isolate which pair and then which injector was the bad 0ne. If
you don’t have a bunch of old injectors to check then this does provide any
benefit.
Yes, you can always
pull the electrical connector on the injectors, but with my primary injectors in
the block behind my intake manifold – it is not an easy job. Switches make
it easier.
No fuses, but I do have
Circuit Breakers in those lines, so you are correct - a shorted wire should
cause no ultimate problem that the popping circuit breaker wouldn’t take care
of.
Agree, you can kill the
engine any number of ways. However, early on the EC2 had a sneak circuit
that provided sufficient power through the injector power wires to the old EC2
(long ago corrected) to continue to power it. So you can imagine my
surprise after I first installed the EC2 and turn off the power to it a (but not
the injectors) – the engine continued to run. So not knowing what was
going on , I killed the engine using my injector switches and found I like the
way that brought the engine to an immediate stop.
Yes, you can turn off
the fuel pump but there is still pressurized fuel in there for a moment or two
that can continue to inject into your engine until the pressure drops down.
You can turn of the ignition and ditto. Again no biggie, but I like
the way the engine stops when the injectors are turned off – there is No wind
down, the engine stops producing power
immediately.
Again, was as not
trying to get you to change your wiring, just providing my viewpoint on my
preference .
Ed
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Tuesday, March 16, 2010 10:22
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Injector Select
Switch [FlyRotary] Re: Civil Discourse was : [FlyRotary] Re:
Ut-Oh...
1) Have you ever had an injector
failure that required this?
2) There were a number of
occasions during initial debug when it was helpful to disable injector pairs. It
was easy enough to do this by pulling power where they were plugged into the
essential bus. Not as convenient as flipping a switch, but I don’t anticipate
having to mess with it ever again.
3) Are your supply lines to your
injectors fused? If not, why not? If they do short in flight how do you
know to turn off the switches?
4) I turn off the fuel pump to
kill the engine. I suppose this does leave a possibility of a little fuel in the
chamber? Not sure there is any reason for
concern?
Sent: Tuesday,
March 16, 2010 6:30 AM
Subject:
[FlyRotary] Injector Select Switch [FlyRotary] Re: Civil Discourse was :
[FlyRotary] Re: Ut-Oh...
I also find the
“Injector Select” switches useful for several purposes, Rino.
1. If a problem
with one injector of a pair occurs, I can turn that pair off and fly home on the
remaining pair.
2. They are great
for trouble shooting injector problems by permitting you to choose which pair
will be on without question.
3. In the highly
unlikely (but possible) event that a power wire to a pair should short to
ground, you can turn the power off to that pair.
4. I also use them to
turn off the engine – that ensures no residue fuel in the
housings.
But, if not wired
correctly they can cause a new installation some puzzling problems {:>) and
they do add another component and we know components can fail – although if
sized properly for the correct current and installing quality switches and wire
correct the failure in one will not take you down and the likelihood of both
failing at the same time is rather remote.
But, once again, you
can certainly fly without them – I just find them very
useful.
My
0.02
Ed
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Rino
Sent:
Tuesday, March 16, 2010 8:05 AM
To: Rotary motors
in aircraft
Subject: [FlyRotary] Re: Civil Discourse
was : [FlyRotary] Re: Ut-Oh...
I find the "injector
failure Switches" convenient during the warmup to test the operation of the
injectors just like the primary and seconday plugs
test.
----- Original
Message -----
Sent: Tuesday, March 16,
2010 1:23 AM
Subject: [FlyRotary] Re:
Civil Discourse was : [FlyRotary] Re:
Ut-Oh...
I chose not to
implement the "injector failure switches". I don’t know if there are any
statistics on it, but I suspect injector failure is an extremely
rare occurrence. On the other hand if one did fail I'd rather fly the
plane and troubleshoot the problem after I'm on the ground. But that’s
part of the advantage in going the Experimental route - build it the way you
want it.
Sent: Monday, March 15,
2010 8:47 AM
Subject: [FlyRotary] Re:
Civil Discourse was : [FlyRotary] Re:
Ut-Oh...
In the event of a
primary or secondary injector failure, the affected injector set can be
switched off and the cold start switch used to richen up the remaining
injectors. This as per Tracy's instructions. I haven't tried this,
and hope I never have to in the heat of battle, but there it is.
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__________
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