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Static port question

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rv10(at)sinkrate.com
Guest

Posted: Mon Sep 04, 2006 6:50 pm Post subject: Static port question

Does anyone have any pictures of how they ran their static port tubing?  Did you drill out holes for bushings in the ribs and what size did you use?  I went with the Van’s pop-rivet kit because I never got around to researching anything else and the time has come to install.    

   

Any pointers would be appreciated.  

   

-Ben Westfall  

#40579 Tailcone… still   

   

   

   

       [quote][b]

billderou(at)yahoo.com
Guest

Posted: Tue Sep 05, 2006 11:12 am Post subject: Static port question

Sorry no pictures - but - 

  I believe the only critical item is routing both ports up to the highest point on the nearest bulkhead and then tee off for a single run to the panel. This will drain the water back out the port and not into the instrumentation.

   

  It would also be a good idea to perform a leak test and a flying test. Without a correct static port no instrumentation on your panel can be be accurate.

   

  A simple flying test, derived from a very few observations, is to open your static line inside the cockpit during a flight. The altitude should increase 200 feet (or so). If it decreases then your static port is drawing a vacuum and your airspeeds will be incorrectly low and your altitudes high.

   

  Bill DeRouchey

  N939SB, Flying

  billderou(at)yahoo.com (billderou(at)yahoo.com)

  



Ben  Westfall <rv10(at)sinkrate.com> wrote:

  [quote]              Does anyone have any pictures of how they ran their static port tubing?  Did  you drill out holes for bushings in the ribs and what size did you use?  I went with the Van’s pop-rivet kit because I never got around to researching anything else and the time has come to install.  <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

   

  Any pointers would be appreciated.

   

  -Ben Westfall

jdalton77(at)comcast.net
Guest

Posted: Tue Sep 05, 2006 3:09 pm Post subject: Static port question

Since we're on the static port question, and for  those of you in the know, is there any significant reason, other than  appearance, to go with the SafeAir vs. the Vans "pop rivet?"  For those who  have installed the Cleveland, how about that one.  It sure looks nice and  it's a lot cheaper than the SafeAir.

  

  

  

  

 [quote]   ---

LarryRosen

Joined: 16 Jan 2006
Posts: 415
Location: Medford, NJ

Posted: Tue Sep 05, 2006 5:29 pm Post subject: Static port question

*You can see how Deems the static tubing here

<http://www.deemsrv10.com/album/Sec%2035%20Access%20covers%20and%20Floor%20panels/index.html>

look at pictures DSC03048, 49 & 50.

*

_________________
Larry Rosen
#40356
N205EN (reserved)
<http>

Tim(at)MyRV10.com
Guest

Posted: Wed Sep 06, 2006 6:10 am Post subject: Static port question

New news from me on Static ports.



Note: I know nothing about the SafeAir ones.



I have the original cleaveland ones.  They are supposed to sit

out about .010" from the skin, and you're supposed to paint

them so they do stick out. (Just found that out yesterday).

I've been doing some test flights to check my airspeed accuracy,

and I found that I was about 6.5-7.5kts TAS low in cruise.

My static ports are absolutely flush, unpainted, and even with the

skin.



Last night, I did a test, I took some .050 material, and cut 2

small discs and drilled a small hole.  I stuck those over the

static ports and taped them down with plain old scotch tape.

I test-flew it again and found that I am now only 4 kts off

in my TAS.  So there is definitely some importance to the static

port design on an RV-10.



Yesterday I got on the way from Cleaveland a pair of their newer

static ports.  I saw them on an RV-10 at Van's Homecoming.  They

stick out a ways and are domed in shape.  My guess is that these

will be much better than the original flat ones, based on the

quick and dirty test from last night.



My main point is, make sure you don't have flush static ports,

and that you have at least some part of them sticking out past

the skin.  Again, I don't know what the SafeAir's are like,

and I've never really heard anyone provide any data on playing

around with their airspeed to see if it was accurate.  If you have

the original flush ones or yours don't stick out, perhaps some

machining or filing of the backside of them where they hit the

skin would be in order.  Just make sure they stick out a little.



Also, I encourage you builders to go out once you're flying

and actually gather and provide some data on your planes.

It's pretty rare that we see any true specs beyond the

minimum amount of info, but it's the only way to get good data.

In my case, I want the airspeed as accurate as possible. The

Chelton's calculate TAS, and from the heading offset from

ground track and TAS and Groundspeed, they calculate winds.

This can be pretty accurate, but imagine this:



Groundspeed is 160kts, TAS shows as 157kts, but the TAS is

reading 6kts low.  So the system *thinks* you have a tail wind,

cruising over ground faster than through the air.  In reality,

you have a light headwind.   The lower the winds, and the

larger the error in airspeed, the more incorrect these

values can become.  I'm going to keep playing and hopefully

get my error down to at most a couple KTS.  I have 3 separate

instruments all reading the same airspeed, so it's not instrument

error.



Tim Olson - RV-10 N104CD - Flying

do not archive

jdalton77 wrote:

[quote] Since we're on the static port question, and for those of you in the 

 know, is there any significant reason, other than appearance, to go with 

 the SafeAir vs. the Vans "pop rivet?"  For those who have installed the 

 Cleveland, how about that one.  It sure looks nice and it's a lot 

 cheaper than the SafeAir.

  

  

  

  

 

     ---

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Wed Sep 06, 2006 9:20 am Post subject: Static port question

Here is a shot of the solution Dr. Carl Cadwell used on his Lancair IVP.

Sorry to the string and can folks. That was before he started such a

stir with his Epic LT which has led to the 51% Rule rewrite.



These static ports are critical in their exact location and design for

accurate pressure indication.  Horseshoes and hand grenades are not

going to do it.  You should see what is necessary for RSVM mapping.



John Cox

Do not Archive



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Tim(at)MyRV10.com
Guest

Posted: Wed Sep 06, 2006 10:17 am Post subject: Static port question

Wow, that's the first time I've ever seen such a thing as that.

Very interesting.  Maybe tonight or tomorrow I'll stick something

thick on the plane in front of the port like that just to see

what happens.  I've never used a hand grenade, but M-80's and

firecrackers can be fun. 



Tim Olson - RV-10 N104CD - Flying 138 hrs

do not archive

John W. Cox wrote:

 	  Quote: 	
		   Here is a shot of the solution Dr. Carl Cadwell used on his Lancair IVP.

 Sorry to the string and can folks. That was before he started such a

 stir with his Epic LT which has led to the 51% Rule rewrite.

 

 These static ports are critical in their exact location and design for

 accurate pressure indication.  Horseshoes and hand grenades are not

 going to do it.  You should see what is necessary for RSVM mapping.

 

 John Cox

 Do not Archive

Rick S.

Joined: 12 Feb 2006
Posts: 347
Location: Las Vegas

Posted: Wed Sep 06, 2006 11:44 am Post subject: Static port question

That's not all that unusual, it seems a bit extreme but it does allow the air to breakup over the actual port. If I recall the oply problems folks have had with the Cleaveland ports (I'm using those) is making them flush with the skin. I think Mike piped in about the face of the port needs to be a thousandth or so above the actual aircraft skin otherwise the hole will act like a venturi and create a negative static pressure as the airflow passes over the static port.



Rick S.

40185

_________________
Rick S.
RV-10
40185

indigoonlatigo(at)msn.com
Guest

Posted: Wed Sep 06, 2006 12:42 pm Post subject: Static port question

Not that I really know, but doesn't this venturi happen anyway and isn't 

that why there is a port on both sides of the fuselage to cancel out the 

negatives and positives of the other port?



My sailplane has a total of six in the tail boom located 120 degrees apart 

and they are as flush as they can be.



John G.

 	  Quote: 	
		  From: Rick <ricksked(at)earthlink.net>

Reply-To: rv10-list(at)matronics.com

To: rv10-list(at)matronics.com

Subject: RE: Static port question

Date: Wed, 6 Sep 2006 12:43:31 -0700 (GMT-07:00)






That's not all that unusual, it seems a bit extreme but it does allow the 

air to breakup over the actual port. If I recall the oply problems folks 

have had with the Cleaveland ports (I'm using those) is making them flush 

with the skin. I think Mike piped in about the face of the port needs to be 

a thousandth or so above the actual aircraft skin otherwise the hole will 

act like a venturi and create a negative static pressure as the airflow 

passes over the static port.



Rick S.

40185

Tdawson(at)avidyne.com
Guest

Posted: Wed Sep 06, 2006 1:03 pm Post subject: Static port question

No kidding.  I'm in Cali for a few days with the Air Force Reserve, and we had to plow out here at FL280 because, even though our RVSM modification has been done, the FAA is taking it's time with the paperwork!  And plowing along at that altitude meant we had to make a fuel stop because we can't take off from our home base with a full load . . . 



TDT

40025

Do not archive



________________________________



From: owner-rv10-list-server(at)matronics.com on behalf of Tim Olson

Sent: Wed 9/6/2006 2:17 PM

To: rv10-list(at)matronics.com

Subject: Re: Static port question






Wow, that's the first time I've ever seen such a thing as that.

Very interesting.  Maybe tonight or tomorrow I'll stick something

thick on the plane in front of the port like that just to see

what happens.  I've never used a hand grenade, but M-80's and

firecrackers can be fun. 



Tim Olson - RV-10 N104CD - Flying 138 hrs

do not archive

John W. Cox wrote:

 	  Quote: 	
		   Here is a shot of the solution Dr. Carl Cadwell used on his Lancair IVP.

 Sorry to the string and can folks. That was before he started such a

 stir with his Epic LT which has led to the 51% Rule rewrite.



 These static ports are critical in their exact location and design for

 accurate pressure indication.  Horseshoes and hand grenades are not

 going to do it.  You should see what is necessary for RSVM mapping.



 John Cox

 Do not Archive

Tim(at)MyRV10.com
Guest

Posted: Wed Sep 06, 2006 1:29 pm Post subject: Static port question

I think it would depend on the plane and the location for how it

all works in the end.  I'm not sure I agree with what Rick said

below though exactly the way he said it.  It would seem to me

that if you had a venturi effect giving a little negative

pressure to the static system that you could end up with an

airspeed reading that would be HIGH, since the differential pressure

would be greater....not low.  Mine is 6.5-7.5kts low with the

flush ports, and with them sticking out it's more like 4

so far.  I'm hoping to figure out exactly what dynamics make it

perfect.



Tim Olson - RV-10 N104CD - Flying

do not archive

John Gonzalez wrote:

 	  Quote: 	
		   

 

 Not that I really know, but doesn't this venturi happen anyway and isn't 

 that why there is a port on both sides of the fuselage to cancel out the 

 negatives and positives of the other port?

 

 My sailplane has a total of six in the tail boom located 120 degrees 

 apart and they are as flush as they can be.

 

 John G.

 

 

> From: Rick <ricksked(at)earthlink.net>

> Reply-To: rv10-list(at)matronics.com

> To: rv10-list(at)matronics.com

> Subject: RE: Static port question

> Date: Wed, 6 Sep 2006 12:43:31 -0700 (GMT-07:00)

>

> 

>

> That's not all that unusual, it seems a bit extreme but it does allow 

> the air to breakup over the actual port. If I recall the oply problems 

> folks have had with the Cleaveland ports (I'm using those) is making 

> them flush with the skin. I think Mike piped in about the face of the 

> port needs to be a thousandth or so above the actual aircraft skin 

> otherwise the hole will act like a venturi and create a negative 

> static pressure as the airflow passes over the static port.

>

> Rick S.

> 40185

>

>

dlm46007(at)cox.net
Guest

Posted: Wed Sep 06, 2006 1:51 pm Post subject: Static port question

I believe the static port each side plumbed together is intended to help 

cancel out slips and skids which might cause higher or lower pressures than 

normal. Now about the yaw damper.

---

dlm46007(at)cox.net
Guest

Posted: Wed Sep 06, 2006 1:54 pm Post subject: Static port question

BTW the static ports on my certified Cardinal RG were each side of the 

fuselage just forward of the doors and were a 40 hole in the skin. 

completely flush.

---

dlm46007(at)cox.net
Guest

Posted: Wed Sep 06, 2006 2:00 pm Post subject: Static port question

One other thought; My certified pitot tube on the Glastar has the static 

ports in the pitot tube and flush to the side of the pitot tube . They are 

four holes in a line on the bottom (parallel to the wing) and four holes on 

a line on the top. probable reason to compensate for the angle of attack of 

the wing at any given moment.

---

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