Dual airspeed indicators

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Dual airspeed indicators

Postby monte.yarger » Thu Oct 02, 2014 10:12 am

I am laying out my instrument panel and want to have a small backup airspeed indicator for the EFIS. Can I simply "T" into the pitot line for both or is it more complicated than that? Have been trying to research it without much luck and was hoping someone may have done this previously. Some questions thar run through my small brain: How do they do it on tandem seat aircraft with 2 airspeed indicators? Wasn't sure if there would be a loss of accuracy by splitting the air pressure? 2 separate pitot tubes seems like overkill. I have a single low budget pitot/static tube from aircraft spruce on left wing. Thanks for any feedback!

Monte Yarger
Waiex 94 Jab 3300
Retired Navy!
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Re: Dual airspeed indicators

Postby gammaxy » Thu Oct 02, 2014 10:39 am

A "T" will be no problem. The pressure doesn't get split--it should be the same everywhere within the system.
Chris Madsen
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Re: Dual airspeed indicators

Postby kmacht » Thu Oct 02, 2014 11:32 am

monte.yarger wrote:I am laying out my instrument panel and want to have a small backup airspeed indicator for the EFIS. Can I simply "T" into the pitot line for both or is it more complicated than that? Have been trying to research it without much luck and was hoping someone may have done this previously.


I did the exact same setup in my plane. I have a T in the line where one side goes to a backup airspeed indicator and the other goes to the EFIS. Shouldn't be a problem.

Keith
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Re: Dual airspeed indicators

Postby daleandee » Thu Oct 02, 2014 12:00 pm

monte.yarger wrote:I am laying out my instrument panel and want to have a small backup airspeed indicator for the EFIS. Thanks for any feedback!

Monte Yarger
Waiex 94 Jab 3300
Retired Navy!


Monte,

I considered the same thing you are doing and decided I could have redundancy and a more useful instrument by installing a Lift Reserve Indicator instead of a second airspeed indicator. Here's a link to a recent conversation about LRI instruments:

http://sonexbuilders.net/viewtopic.php?f=21&t=714&p=10065&hilit=lift+reserve+indicator#p10065

Just some food for thought ...

Dale
N319WF

PS: Thank you sir, for your service!
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Re: Dual airspeed indicators

Postby Rynoth » Thu Oct 02, 2014 7:01 pm

Lri is a great backup for airspeed since it's another probe and set of lines. Going with a T still means that if something happens to your pitot/static lines, both airspeeds will be gone.
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Re: Dual airspeed indicators

Postby fastj22 » Thu Oct 02, 2014 8:05 pm

Rynoth wrote:Lri is a great backup for airspeed since it's another probe and set of lines. Going with a T still means that if something happens to your pitot/static lines, both airspeeds will be gone.

I had dual ASI, one digital one analog with a simple T in the lines. Worked well.
When I upgraded to the LRI, I took out the analog ASI and the Ts.

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Re: Dual airspeed indicators

Postby monte.yarger » Fri Oct 03, 2014 5:35 am

Thanks to all....I will consider the LRI. A little concerned how to route and mount the tubing now that my wings are closed in but I'm sure I could figure it out.
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