Dual airspeed instruments questions

Fisrt of all, Thanks for all of the great information. It helps a bunch.
As for why I need two airspeed indicators, I'm planning to use a standard
airspeed indicator (read cheap) to start with, and I want to eventually
place a Dynon Aviation EFIS-D10 in the panel when I'm finished. I just
wanted to know if I needed to replace my old airspeed indicator or could tee
in the new instrument. Plus I didn't want to have to add a second
pitot/static system if I didn't have to. Thanks again

Louis G.

"Jay" wrote in message
om...
Curious why you would do that in the first place? Couldn't you get
away with GPS speed (average of 2 runs in opposite direction to pull
our windage) to check your differential air pressure based airspeed
instrument.

Also, if you put 2 instruments on the same ports, one of the biggest
sources of error (port placement) will be applied equally to both
instruments.

I'm leaning towards the idea of an all electronic panel (GPS centric)
with minimum no-electric emergency cluster.

Regards

"Louis Gallego" wrote in message
news:kdMKb.80815$xX.581325@attbi_s02...
Does anyone know how one would install two separate airspeed indicators?
I
suspect one would need a separate pitot tube systems. Is this correct?
Also, how does one go about correcting an error (either too fast or
slow) in
the indicator. I'm 2/3 done with the fuselage of my Zenith Zodiac 601XL
and
was just thinking ahead.
Thanks in advance,

Louis G.

From: "karel adams"


"Ron Natalie" schreef in bericht
om...

"Rob Turk" wrote in message
all.nl...
"Eric Miller" wrote in message
et...

Use a tee fitting just as you would for a static source; you only
need one
pitot system to supply two ASIs.


A problem (bug, dirt, ice) in the pitot would influence both ASI's.
Two
pitots makes sense if you install dual ASI for redundancy.

And two statics wouldn't be a bad idea either. On larger aircraft
the pilot and
copilot have independent static sources as well.

I've had two static system failures and one pitot failure over 25
years of flying.
All were the result of some foreign object lodged in the tubing (2 mud
daubers
and a gooey piece of something which we weren't quite sure what it
was).

I've also come out and found the static ports taped over after
maintenance.

In the "Instruments" chapter of my PPL ground school,
I was taught that many planes have two static ports
and a three-way valve to select between
"static" and "alternate static"

KA

On T-39s we had 4 static sources: 2 pilot and 2 copilot. One on each side was
an alternate and mounted in the nose wheel well. The select switches were
mounted on the lower outboard corners of the instrument panels.

Dan, U.S. Air Force, retired

From: "Eric Miller"
Date: 1/7/2004 3:02 PM Central Standard Time
Message-id:


"Ron Natalie" wrote in message
om...

In my own plane, I was amused in that I do have two static ports (they are
teed together from opposite side of the plane). The mud dauber managed
to climb in past the tee to plug the thing up totally.

You gotta respect a bug that goes to *that* much trouble to ruin your day!

Eric

And hope he doesn't have relatives in your area.

Dan, U. S. Air Force, retired