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Posted for "Ted Noel" <tednoel@cfl.rr.com>:
Gary,
Does your system work from the suction side of the turbo? That makes a
lot of sense, and suggests that all-electric might not be so bright. As long
as the stick is turning, you would have vacuum. How much can it create?
Ted Noel
All-electric L-IV-P
----- Original Message -----
From: "Gary Casey" <glcasey@adelphia.net>
Lots of good posts on the subject - go to the "aero-electric" list as
suggested by some to get multiple pro all-electric opinions. On my ES I
am
going to an electronic engine control, so it will have a redundant
electrical system, but still a vacuum gyro. Why? Mostly because I have
this (patented) pressure regulator that will operate vacuum gyros from a
turbocharged engine (mine is) with no vacuum pump. So the plane will be
sort of a flying test bed/tax write-off. Otherwise the all-electric
scheme
would maybe be the way I would go.
However, I believe you can fly safely with the older, cheaper systems.
Here's what I did on my Cessna for just that purpose: I have a vacuum
system with no backup and a standard electrical system (also no backup).
The backup for the vacuum system is my S-TEC autopilot, which I chose
specifically because it is all-electric, getting it's information from the
turn coordinator. The on/off button for the A/P is on the yoke so I don't
have to reach for it. I consider that to be more effective backup than a
backup vacuum system (more expensive, too - but the vacuum system won't
fly
the plane for me). I consider the A/P to be almost a no-go item for an
IFR
flight and I turn it on and check it on the ground as a pre-flight item.
The A/P is also the backup for the other single-failure-mode system; me.
I
show regular right-seat passengers (my wife) how to turn on the A/P to
level
the wings. For my ES I plan to install the Autotrak A/P system which has
internal electric gyros. I do change the vacuum pump every 700 hours for
peace of mind, but I see no statistical proof that it is a good
prevention.
I've had both pump and instrument failures, including turn coordinators,
over the years.
Gary Casey
ES project
C177RG
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