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Old 11-27-2011, 09:51 PM
stevengrasley stevengrasley is offline
Join Date: Oct 2011
Location: Marathon, FL
Posts: 40
Default How many pitot's do you need?

When configuring a -7A for IFR with a glass cockpit is seems the wisdom out there dictates to also install some steam gauge backups. If so, then can a single pitot work for the EFIS ADAHRS and the steam gauge? May sound like a dumb question but I have asked several folks... including AP's...and the range of answers is somewhat astounding. What is the input from the VAF crowd?

RV-7A, N783RV
Flying since 10/1/2013 Tach: 1450+ hours
Lyc O-360-A1A
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Old 11-27-2011, 10:00 PM
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AltonD AltonD is offline
Join Date: Sep 2005
Location: Dothan, Alabama
Posts: 1,492

I have one pitot feeding an autopilot, steam airspeed, and an AFS3500. There is no flow in the pitot line.
Alton DeWeese
N526RV RV7A Tip Up, IO360 180 W/Hartzel BA prop.
Flying ~950 hours since Aug 2010

Construction Log
?The secret of getting ahead is getting started. The secret of getting started is breaking your complex overwhelming tasks into small manageable tasks, and then starting on the first one.?

?Mark Twain
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Old 11-28-2011, 06:05 AM
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pierre smith pierre smith is offline
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,885
Default Yep

Since there really isn't any "flow" but rather pressure, you can use one pitot for multiple points.

My -10 has it to a D-100, a standby AS and the TruTrak autopilot.

Rv10 Sold
46 years ag pilot/CFI
Air Tractor 502/PT-6
Building RV-12, Wings, fuse, emp complete. FWF in progress.
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Old 11-28-2011, 08:09 AM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,462

For my IFR aircraft, I use a single Pitot (been flying that way for decades in spam cans...). Pitot heat should take care of ice (although I flight plan to avoid evene the potential of icing, or I don't go!) - you are susceptable to a perfectly aimed bug of course. I personally consider that a low risk.
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
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Old 11-28-2011, 08:35 AM
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JoeM JoeM is offline
Join Date: May 2011
Location: Perryville, MD
Posts: 93

Just my opinion as a not yet pilot or aircraft owner but it seems the most likely item to cause a failure of the airspeed/altimeter indications would be leaks or clogging of the pitot/static probes and lines. I would see nothing wrong with separate systems.
Joe Mikus
MSgt USAF Ret Avionics Tech
Perryville, MD
Student Sport Pilot
Future RV-12 Builder?
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Old 11-28-2011, 08:57 AM
Sid Lambert Sid Lambert is offline
Join Date: Jul 2005
Location: North Atlanta
Posts: 1,120

One for each pilot on-board.
Sid Lambert

RV-7 Sold
RV-4 - Flying - O-320 Fixed Pitch - Red over Yellow

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Old 11-28-2011, 09:12 AM
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Mark12A Mark12A is offline
Join Date: Jun 2011
Location: Huntsville, AL
Posts: 89
Default Sid Stole It...

I quickly read through the thread title and I though it said, "How many pilots do you need?"

That sounds like the entry line for any number of crude jokes. Especially around fighter pilots.
Jay Staub
Lt. Col., USAF, Ret.
N6565S Reserved
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Old 11-28-2011, 09:32 AM
krw5927 krw5927 is offline
Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,966

Put 2 pitots in and you'll always wonder which one's right. Small chance they'll both read exactly the same.

Kind of like asking a guy with 2 watches what time it is.
Kurt W.
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Old 11-28-2011, 09:57 AM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,654

Originally Posted by Ironflight View Post are susceptable to a perfectly aimed bug of course. I personally consider that a low risk.
If you don't use a pitot cover on the ground, there's a much higher chance for a clogged pitot due to a bug. Happened to me once.

Now I use one of those flip-up-in-the-wind covers, test it on preflight, and in the next 1,400 hours of mostly rural airports, have had no problems and no cover malfunctions.

Here's a link to one:

The only issue with these is that they pop open during the take-off roll and the airspeed needle swings wildly for a second right when you'd like to have it work. As a result my take-offs are by feel. And before lift-off everything's fine. The gadget is recommended.

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Old 11-28-2011, 02:05 PM
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Don Don is offline
Join Date: Jan 2005
Location: Richmond, VA
Posts: 696

Originally Posted by Sid Lambert View Post
One for each pilot on-board.
I read it correctly but my first thought was, 'It depends on how many airplanes you own.' I prefer having one pitot for every plane I own. Right now I have two pitot tubes but I might need a third on soon<g>...but the wife doesn't share my opinion...yet.
Don Alexander
RV-9A 257SW Purchase Flying - O-320, Dynon D100
RV-9A 702DA (reserved) Finish Kit IOX-340
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