Static ports
Posted: Thu Mar 25, 2021 12:47 pm
by wingnut99
So what is the conventional wisdom on static ports location?
I was thinking just behind the cockpit 8 or10 inches and a little below the top longerons which would put it below the ADHARS on the panel so there’d be no chance for water to make it’s way up there. That should be far enough above the wing and away from the prop. Seems to be in line with the Dynon recommendations but I don’t necessarily trust my interpretation of anything I read. I’m just hoping my Waiex doesn’t fly sideways and upside down. At least I’ll get to fly it once if it does.
Re: Static ports
Posted: Fri Mar 26, 2021 10:59 pm
by Jim1342
Google: “Static Port Location and Altitude Calibration, Reinhard Metz” for a complete procedure for determining the static port location.
Re: Static ports
Posted: Sat Mar 27, 2021 11:02 am
by Scott Todd
Or you can put it on the Pitot probe. You can male your own or buy one. Here is a simple one from Spruce. Its replaceable, cheap, and simple. 15144.
Re: Static ports
Posted: Sat Mar 27, 2021 11:54 am
by BRS
That’s the one I installed. Did it mainly because the pitot tube needed replacing and it was was easy to put them both in the same place. If I didn’t have to contend with a pitot tube then for sure I would put the static port(s) on the fuselage just to keep things nice and clean.
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I once owned a Diamond DA40 (fabulous aircraft) that had an autopilot oscillation issue. It was due to poor static-port placement. The solution was an optional service bulletin to install two static ports just aft of the rear cabin bulkhead, one on each side. I believe “each-side” was to nullify any error due to yaw. The two ports were connected by a tube that went up (not down) to a “T”. Going ‘up’ is to prevent moisture from collecting and blocking the tube thus causing errors.
Re: Static ports
Posted: Sat Mar 27, 2021 2:25 pm
by wingnut99
That’s pretty much what Dynon recommended but all plane’s are different so who knows for sure. I have the HDX which has the synthetic vision and the static ports combined with their pitot tube all work together to provide the synthetic vision. I’m about done with the panel and need to hook up the ADHARS with all the tubes while I still have easy access to it on the bench. It ought to be sweet if I did everything right.
Re: Static ports
Posted: Mon Mar 29, 2021 1:58 pm
by lgsievila
Wingnut,
Tried your prospective location on my Onex and they did not work there. Used the Dynon Provided ports with my Skyview when I installed the Dynon AOA Pitot tube. Ended up going back to my original location under the wing using the pitot portion of A/C Spruce pictured above so I have 2 pitot tubes under my right wing. My opinion you would have to be further back on the fuselage like some RV’s .
Re: Static ports
Posted: Tue Apr 06, 2021 11:59 am
by wingnut99
Thanks for the feedback. Unfortunately I already installed them. I talked with David at Dynon prior to that but he didn’t offer any exact location. Guess I’ll find out if they are going to work when I get airborne eventually.
Re: Static ports
Posted: Tue Apr 06, 2021 12:00 pm
by wingnut99
Thanks for the feedback. Unfortunately I already installed them. I talked with David at Dynon prior to that but he didn’t offer any exact location. Guess I’ll find out if they are going to work when I get airborne eventually.
Re: Static ports
Posted: Tue Apr 06, 2021 3:08 pm
by lgsievila
I had contacted Dynon as well and they didn’t have a good answer for me either. I would caution you to be sure of your IAS as mine was high at least 10 mph with static port in wrong place.
Re: Static ports
Posted: Tue Apr 06, 2021 3:33 pm
by wingnut99
Yeah I’ll be keeping a sharp eye on the GPS. It might be detectable in a high speed taxi.
Re: Static ports
Posted: Tue Apr 06, 2021 3:33 pm
by wingnut99
Yeah I’ll be keeping a sharp eye on the GPS. It might be detectable in a high speed taxi.
Re: Static ports
Posted: Tue Apr 06, 2021 7:51 pm
by lakespookie
Best way to correlate the static reading is with a cone test.
Re: Static ports
Posted: Tue Apr 06, 2021 11:20 pm
by BRS
lakespookie wrote:Best way to correlate the static reading is with a cone test.
what is a cone test?
Re: Static ports
Posted: Tue Apr 06, 2021 11:56 pm
by Bryan Cotton
I think he means a trailing static probe. That seems like overkill. We used to do something similar in flight test at Sikorsky for new aircraft designs. Why not just see how your static system works? Fly with somebody’s Cessna and do altimeter checks. If your static system is off either try moving it or do like we did at Schweizer - tweak with fences in front of or behind the port.
Re: Static ports
Posted: Wed Apr 07, 2021 10:04 am
by builderflyer
Now that we have GPS, using a trailing cone to determine static system error seems a bit outdated. My Sonex has the homebrew pitot-static system as shown on the plans. Initially the airspeed indicator read about 10% high at cruise speeds due to the static pressure being too low. The cure, through trial and error, was to add a collar of varying dimensions behind the static ports on the static tube until just the right combination was found. Subsequently, the airspeed indicator reads correctly (IAS / CAS) within 1 or 2 mph from 90 mph to 190 mph. Can’t do much better than that but I’d still like to move the static ports to the sides of the fuselage and get rid of the ugly static tube beneath the wing especially since there is also a pitot tube and AOA tube there as well.
Art,Sonex taildragger #95,Jabiru 3300 #261
Re: Static ports
Posted: Sun Apr 11, 2021 10:22 pm
by lakespookie
Bryan Cotton wrote:I think he means a trailing static probe. That seems like overkill. We used to do something similar in flight test at Sikorsky for new aircraft designs. Why not just see how your static system works? Fly with somebody’s Cessna and do altimeter checks. If your static system is off either try moving it or do like we did at Schweizer - tweak with fences in front of or behind the port.
You are right it would be a bit overkill but it is effective and pretty much spot on in most cases.
Re: Static ports
Posted: Fri May 07, 2021 9:43 am
by wingnut99
I wish some of the plans provided a little more exact information but as long as I have access to all you guys, I’ll be fine. Besides, the worst that can happen is moving them or using the fence approach. If I move them I get to plug the holes with disco lights!