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Hey Paul,
I Appreciate your 2 cents, there is a lot to
consider. When I purchased the aircraft it was a MARGINAL VRF panel, I
have a IO 550 with dual Mags. The EFIS is OP TECH with a AHRS but it wired to
it's own switch. The Avionics Master was just to power the radio stack and the
encoder for ease of operation vs: turning on and off the individual 5 switches.
I have an all electric panel with electric backup 2 1/4 ADI, ALT, VSI and
Airspeed. I'll fly some light to marginal IFR. I never need to get anywhere that
bad, but it nice to have the equipment for when you do run into the unexpected.
I really appreciate every ones feed back, I'm new to this sight and it's been a
Great Help. Paul, I was thinking about just adding another battery for a backup,
but I think I may go with the second 20 amp alt. and a single Battery. Thoughts
???
Thanks again
Jeff
----- Original Message -----
Sent: Wednesday, September 26, 2007 2:06
PM
Subject: [LML] Re: Lancair Legacy
Avionics Master Switch Wiring Question
Jeff,
To your first
question on batteries/alternators I have several
questions.
- Are you using magnetos or
electronic ignition? If you have dual electronic ignition I consider dual
batteries/alternators essential. If you have a single electronic/single mag
system then you need to seriously consider what happens if you lose the
source to the electronic system?
- Are you’re instruments all
electric or do you have vacuum power backup? If all electric then I would
again strongly consider dual batteries/alternators
Considering the
avionics master I have to ask why you want one. The avionics today are very
tough. I don’t consider them necessary. On the other hand, if you have dual
power busses, and radios split between them for redundancy, then you need
either no avionics master switches or two of them (one for each buss). A
single switch is a single point failure.
Does your glass panel
have an AHRS? If so you may wish to power it from both busses (thru diode
isolators). Many of these cannot restart in flight and inadvertent hitting of
an avionics master could render your primary flight display useless for the
remainder of the flight.
These and many others
have run through my head and been discussed here many times. I spent many
years designing missile test range tracking and safety systems. It’s not
an easy question. First you need to understand how you intend to use your
aircraft, and what could happen during failures. Try to write it out if you
can to help clarify your expectations. The worst time to figure out how the
system should work is in hard IFR when the lights starting to dim.
My two
cents
Paul
Bricker
N63PB
From:
Lancair Mailing List
[mailto:lml@lancaironline.net] On Behalf Of
jeff@eurocars4less.com
Sent: Tuesday, September 25, 2007 9:55
PM
To:
lml@lancaironline.net
Subject: [LML] Lancair Legacy Avionics
Master Switch Wiring Question
First time user on LML.
Marv's been very helpful in getting me started. Thanks
Marv!!
Working on re-building a Legacy
Panel. Wanted to get some thoughts on Battery
/alt. systems for the Legacy. read thru aero connections, (lots of options)
but wanted to get some real world feedback from builders and owners on
the different set-ups. Dual battery w/ single 60 amp alt. vs: dual alt. ( 60
& 20 amp) with single battery, or dual / dual. I have a single alt /
single battery setup now, wanted to see if it was worth changing
things around now while everything is apart. Going from a marginal VFR
panel to an IFR OP TECH . glass panel with a Garmin Stack. Any Thoughts
??? Thanks
My second question, was on
wiring a Garmin stack to an avionics master switch purchased from
Lancair. The rocker switch is rated at 15 amps, needless to say the radio
stack runs allitle over the switches capacity. I guess I'll have to use a 30
AMP relay for the switching. Any info. on finding the correct relay to
use, wiring insights, schematics, ect. . . would be
appreciated.
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