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12-21-2010, 09:36 AM
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Join Date: Jan 2010
Location: Hingham Mass.
Posts: 64
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Quote:
Originally Posted by rleffler
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Thank you Bob.
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RV-10
Wings
N71TR
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12-21-2010, 02:04 PM
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Join Date: Nov 2009
Location: Palo Alto, CA
Posts: 22
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Correct in software?
I'm curious -- with the combination of widely-used EFIS devices and static port errors... Why can't the errors be corrected in software?
I understand why a bad static port can't be fixed for an analog gage, since the gage assumes a fixed (linear?) relationship between static and pitot pressure. But what about for an EFIS? Can't you just do a series of flight tests at assorted known altitudes and airspeeds (say, flying in formation with a calibrated aircraft), plug in "this is how fast and high I am" and derive the pressure curves for your particular plane and installation?
I am a new builder, so please forgive my ignorance. I'm just curious why we have to go to such efforts with physical kludges when this sounds like a software problem to me.
Chris
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12-21-2010, 02:22 PM
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Join Date: Mar 2006
Location: Rhinelander, Wi
Posts: 85
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static ?
My question----Has anybody tried 2 ports, one on each side of fuse, tied to static system on left and right sides of the instrument plumbing? Sort of an "averaging" of pressures. ignorance is bliss 
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RV-9 -- 0-320 -- 993RV--
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12-21-2010, 03:54 PM
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Join Date: Oct 2005
Posts: 1,516
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Dual Static Ports
I thought everybody uses dual static ports?
__________________
Ernst Freitag
RV-8 finished (sold)
RV-10 Flyer 600 plus hours
Running on E10 mogas
Don't believe everything you know.
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12-21-2010, 05:32 PM
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Join Date: Mar 2010
Location: Cleveland, OH
Posts: 69
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Quote:
Originally Posted by mark schoening
My question----Has anybody tried 2 ports, one on each side of fuse, tied to static system on left and right sides of the instrument plumbing? Sort of an "averaging" of pressures. ignorance is bliss 
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Quote:
Originally Posted by N427EF
I thought everybody uses dual static ports?
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Yea, most planes have a static port on either side of the plane, and these are tied into a Tee, which then is the static tube. Just imagine only having one static port in a crosswind.
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Alex
5.0 hours towards my ticket.
Just need to finish college and buy a kit...
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12-22-2010, 10:53 AM
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Join Date: Oct 2007
Location: Belvidere, IL
Posts: 169
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If you want to install an untested static port on an IFR airplane, it would be advisable to test it. I suppose you could do this with a home-made trailing static cone and use a water manometer to compare the two static sources.
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David Shelton, Aerospace Engineer and Soaring Nut.
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12-22-2010, 01:51 PM
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Join Date: Aug 2006
Location: Taylor Texas
Posts: 811
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easy fix!
Quote:
Originally Posted by jjconstant
I have a heated pitot tube with the static ports on the tube as well. I have been calibrating my airspeed and there is a HUGE error in airspeed. I've made several attempts at a kluge fix and, while the airspeed is now within 2 1/2 kts at 160kts and 1 kt at 100kts, it indicates stall at 38 kts.
snip
Jeremy Constant
7A 95hrs, down for annual and squawk fixes
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Hey Jeremy:
Homey Depot sells the fix for your expensive heated pitot/static -- 1/16" rubber O rings! Install aft of the static holes to fix a fast-reading ASI, or in front of the holes for a slow-reading ASI. Keep making low passes at your home field (or another with a known elevation) to check your 'calibration' using your altimeter as the reference instrument. Once you get it right, a bit of RTV or Pro-seal will hold the O ring in place.
Every aft mounted static port I checked netted a 15% error @ cruise: look at the MPH scale and read it as knots. This was true using factory parts and location...YMMV of course!
FWIW, the altimeter is the only instrument you can actually use to check your static system. Use the low-pass method to see what yours tells you, and adjust from there. Do not rely on a pitot/static check to tell you that your static system actually works as it should in flight!
Carry on!
Mark
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12-22-2010, 02:45 PM
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Senior Curmudgeon
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
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Quote:
Originally Posted by F1Boss
the fix for your expensive heated pitot/static -- 1/16" rubber O rings! Install aft of the static holes to fix a fast-reading ASI, or in front of the holes for a slow-reading ASI.
Mark
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O.K., are you cutting them in half first? so they look like the setup in this photo I borrowed from David?

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Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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12-22-2010, 02:58 PM
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Join Date: Nov 2005
Location: KRTS
Posts: 1,798
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I can't believe I'm asking this question, but I can't think of a good answer...
In an unpressurized vessel (i.e. an RV) why can't you get a source of static air from within the plane itself? Something like an open port within the empennage?
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Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
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12-22-2010, 03:24 PM
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Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
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Because the air inside the structure is NOT static. It changes depending on air entering and/or departing the airplane.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
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