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I agree, Al. One thing that Steve mention caused me to recall a small design or rather fabrication detail I make early-on with regard to my electrical connections. I do not use anything but the enclosed circle terminal on any of my critical systems electrical connections. There is no way short of the terminal breaking (or you not putting in the screw {:>)) that it will come loose (well, at least a very low probability {:>)). The only down side is its a real pain in the rear end to have to completely undo a screw to get a terminal loose. I also both crimp/solder and strain relieve with heat shrink tubing all such connections. Not fool proof, but I have not had an electrical problem since I started flying - to the point I have now removed one of my two17AH batteries.
I think the old adage KISS goes a long ways - as you know, it is possible to decrease reliability (not to mention increasing weight and cost) by increasing redundancy pass a certain point - more parts to break.
My design is such that you can even shut off the master switch and the engine will continue to run. Even turning off the power to the EFI CPU it turns out will not cause the engine to shut down (turns out there is an unintended "sneak" circuit that provides an alternative path for power - not one I would wish to rely on for long but still a back up of sorts).
There are two things that will immediately and unequivocally shut down my engine - pulling the ignition CB, turning off power to the injectors, turning off power to both the fuel pumps. In hindsight, I wish I had put each of the ignition modules (lead/trail) on separate CB.
Appreciate you inputs, Al, I can tell by your FEMA on your website you know of what you speak.
Ed A
----- Original Message ----- From: "al p wick" <alwick@juno.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Sunday, December 04, 2005 1:56 PM
Subject: [FlyRotary] Re: Intersting flight
Nice of you to share the information Steve. That represents the best
opportunity for other conversions to be successful. Glad it worked out as
well as it did.
There are all these patterns to failures. I've found it's important to
understand the patterns. Other pilots will read your report, feel
uncomfortable, decide they need to........... but gradually this
discomfort will fade. And they still haven't taken the action they need
to take. So it's important to write down your action list. If you write
it down in 12" high letters and post at your work station, you greatly
increase your chances of taking action...because you've increased social
pressure.
We had a crash just two months ago with exact same root cause. Electrical
failure causes loss of power. Keith too crashed for same reason 2 years
ago. Our installations are at much higher risk than Lyc because we are
power dependant. So we need to be most thorough in this area.
So let's consider the "other" causes.
1) All crashes are the result of change. So when you were improving your
wiring, that change opened you up to new potential failures. So any time
we work on the plane, we take a minute before we close it up to seek the
inadvertent change. We look around, wiggle things, try to find our
oversight.
2) Why don't auto's have this same failure? I noticed on my engine they
have multiple sources for ground. Something like 5 attach points. Two
power sources to ecm. They have all wires in looms, so you can't strain
one wire. Looms have anchors, so you can't strain the looms. So there is
great value in understanding why other installs are successful. We seldom
notice stuff like this.
3) We go brain dead in emergencies. We focus better in some ways, but
lose stuff too. It's pretty interesting. So practicing failure is
valuable. I've found even more effective is using graphics, audible
warnings, computer monitoring. So, the computer would have found that
first 10 ms power blip when you fired up the plane. Perhaps not.
Off soap box. Thanks for sharing info. I've added "review ignition
wiring" to my list.
-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
On Sat, 3 Dec 2005 06:28:46 -0800 (PST) Steve Brooks
<prvt_pilot@yahoo.com> writes:
I made it down to South Carolina, to among other
things, fly the Cozy. It had been 2 months to the day
since I had been down, so the remaining 8 hours of the
40 test hours have been slow to come off.
On Thursday I washed about 30 lbs of dust off of the
plane (open T hanger) and checked everything out. I
did a high speed run down the runway, but didn't have
time to get in a flight.
Yesterday I went to the airport after it warmed up a
few degrees, and took off. The engine was running
very strong in the cooler air (54 degrees). I had
planned to do about a 30 minute flight ad land, just
to check everything out, and was was doing turns and
just cruising around about 6-7 miles from the airport
at about 2900 MSL (2300 AGL). While flying straight
and level, I felt a sudden miss in engine. When I
check the I/P, I also noticed that the digital gauges,
fuel and oil, had rebooted. I immediately started a
turn toward the airport.
About 15 seconds later, I lost total electric. The
I/P went dead, and so did the engine. This isn't
good, I thought. Actually, it was more like, OH SH**.
I took a look at the airport, and I was too far to
make it there, so I looked around, and a 4 lane
highway, which has light traffic appeared to be my
best option. I had just started turning toward that
highway, when the electric power came back, and the
engine picked back up.
I immediately started a climb, and headed toward the
airport again. I already knew that there was a plane
in the pattern doing touch and goes (unicom field), so
I called the airport and advised the other aircraft
that I had a serious issue, and needed to make a
straight in landing.
It didn't lose power again, on the trip back to the
airport, but that 6-7 miles seemed to take forever. I
stayed on the high side on altitude, for obvious
reasons, and then had to bleed altitude (and speed)
while on short final. I came in a little fast, and
touched down earlier than normal, but still was on the
ground, and very happy.
Since I have two separate electrical systems (engine
and everything else), I was really stunned that I lost
both like that. After thinking about it for I while,
I figured out that the master switch was the only
common link. I pulled the I/P cover off, and found
that the ground connector was pulled off of the
terminal and just sitting there barely touching the
contact.
The cause of this was the fact that when I did an
annual on the plane in May, I had added some addition
ty-raps to dress up the wiring a little more. In
doing so, I had stretched the ground wire which runs
to the master switch, which energizes the two master
relays.
It was an easy fix, but now I have to replenish the
adrenalin supply, and figure out how to get the ridge
out of the seat cushion.
After some ground testing, I made another flight
(circling the airport) and everything checked out OK.
I have an emergency bypass switch that will supply
power to the engine systems from either the forward or
aft battery. I didn't think to switch it over, but I
really didn't get to the point of doing any trouble
shooting, so I'm not sure if I would have thought of
that option or not. It was without power for only
about 20 seconds, but it seemed much longer. I will
definitely remember the emergency power switch, should
I every have an issue like that again, but I hope that
never happens.
This isn't nearly as harrowing as some of the
experiences that Ed or John have had, but it was
plenty for me. I don't want any more glider time.
Steve Brooks
Cozy MKIV
Turbo rotary
--
Homepage: http://www.flyrotary.com/
Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/
-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
--
Homepage: http://www.flyrotary.com/
Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/
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