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Dual static line runs?

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tomhanaway

Joined: 12 Aug 2006
Posts: 111
Location: Murphy, NC

Posted: Sun Apr 26, 2009 3:36 am Post subject: Dual static line runs?

Trutrak suggests that a large # of demands on static line may cause lag in auto pilot.  Their suggestion is to run two static lines forward to panel IF this occurs.



My current panel is two AFS 4500's, one AFS 3400, 2&1/4" backup altimeter and airspeed, trutrak adi and vsvg2 autopilot , and 430w garmin stack for demands on static line.



Has anyone actually found a need for a second static line (still using just  the original two static ports) or is one sufficient?



I'd like to avoid second line but if I'm  going to run one, now's the time.



Thanks,

Tom H.

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Sun Apr 26, 2009 5:02 am Post subject: Dual static line runs?

I used that Tygon tubing for static and I've not seen any problems

even with at least 7 items tapped off of it.  I'm not sure if tubing

size for other types of tubing would have an effect or not, but

I can only say that what I'm using seems to be fine.  I'd give

it a try I guess before you worry about pulling more lines, because

unless you add 2 more static ports, I don't know that adding the

additional volume of another line would be a good thing.



Tim Olson - RV-10 N104CD - Flying

do not archive

tomhanaway wrote:

 	  Quote: 	
		   

 <tomhanaway(at)comcast.net>

 

 Trutrak suggests that a large # of demands on static line may cause

 lag in auto pilot.  Their suggestion is to run two static lines

 forward to panel IF this occurs.

 

 My current panel is two AFS 4500's, one AFS 3400, 2&1/4" backup

 altimeter and airspeed, trutrak adi and vsvg2 autopilot , and 430w

 garmin stack for demands on static line.

 

 Has anyone actually found a need for a second static line (still

 using just  the original two static ports) or is one sufficient?

 

 I'd like to avoid second line but if I'm  going to run one, now's the

 time.

 

 Thanks, Tom H.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p 41293#241293

jesse(at)saintaviation.co
Guest

Posted: Sun Apr 26, 2009 5:06 am Post subject: Dual static line runs?

I have not seen the need for 2 static lines.  If you are worried about  

it, you can put your Auto Pilot closest to the static port in your  

routing, then your EFIS, then your backup instruments.



do not archive



Jesse Saint

Saint Aviation, Inc.

jesse(at)saintaviation.com

Cell: 352-427-0285

Fax: 815-377-3694



On Apr 26, 2009, at 7:37 AM, tomhanaway wrote:



 	  Quote: 	
		   



 Trutrak suggests that a large # of demands on static line may cause  

 lag in auto pilot.  Their suggestion is to run two static lines  

 forward to panel IF this occurs.



 My current panel is two AFS 4500's, one AFS 3400, 2&1/4" backup  

 altimeter and airspeed, trutrak adi and vsvg2 autopilot , and 430w  

 garmin stack for demands on static line.



 Has anyone actually found a need for a second static line (still  

 using just  the original two static ports) or is one sufficient?



 I'd like to avoid second line but if I'm  going to run one, now's  

 the time.



 Thanks,

 Tom H.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 41293#241293

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Sun Apr 26, 2009 5:29 am Post subject: Dual static line runs?

I'd keep the altimeter and air data instruments closest in all cases

if you find any issues.  Knowing the correct altitude on an IMC

approach is more important than how quickly the autopilot reacts.



But, I doubt you'd have a problem.



Tim Olson - RV-10 N104CD - Flying

do not archive

Jesse Saint wrote:

 	  Quote: 	
		   

 

 I have not seen the need for 2 static lines.  If you are worried about 

 it, you can put your Auto Pilot closest to the static port in your 

 routing, then your EFIS, then your backup instruments.

 

 do not archive

 

 Jesse Saint

 Saint Aviation, Inc.

 jesse(at)saintaviation.com

 Cell: 352-427-0285

 Fax: 815-377-3694

 

 On Apr 26, 2009, at 7:37 AM, tomhanaway wrote:

 

> 

>

> Trutrak suggests that a large # of demands on static line may cause 

> lag in auto pilot.  Their suggestion is to run two static lines 

> forward to panel IF this occurs.

>

> My current panel is two AFS 4500's, one AFS 3400, 2&1/4" backup 

> altimeter and airspeed, trutrak adi and vsvg2 autopilot , and 430w 

> garmin stack for demands on static line.

>

> Has anyone actually found a need for a second static line (still using 

> just  the original two static ports) or is one sufficient?

>

> I'd like to avoid second line but if I'm  going to run one, now's the 

> time.

>

> Thanks,

> Tom H.

>

>

> Read this topic online here:

>

> http://forums.matronics.com/viewtopic.php?p 41293#241293

>

>

rene(at)felker.com
Guest

Posted: Sun Apr 26, 2009 5:55 am Post subject: Dual static line runs?

I agree with Tim and Jesse and have not seen a need for it.  I also agree

with Tim that I wonder if it even would do any good without another set of

ports.....the tubing ID is so much bigger than the static port opening.  I

am not a fluid dynamics expert....but I did stay in a Condo in Park City

Last night.  I have the following off of may static system....



Backup altimeter

Backup ADI

Backup AS indicator

Autopilot

Grand Rapids EFIS

Blue mountain EFIS

AOA



My autopilot works great....

 



Rene' Felker

RV-10 N423CF Flying

801-721-6080



--

Dick Sipp

Joined: 11 Jan 2006
Posts: 215
Location: Hope, MI

Posted: Sun Apr 26, 2009 5:58 am Post subject: Dual static line runs?

I would have to agree wtih Tim and Jesse, I also have multiple taps and all 

static related indications are

very close.



Dick Sipp

N110DV 130 hours

jim(at)CombsFive.Com
Guest

Posted: Sun Apr 26, 2009 12:14 pm Post subject: Dual static line runs?

That is weird.  Is this specified in the manuals?  There is no flow in either the static or the pitot system, only pressure.  Very low pressures to boot.  Is that something someone told you on the phone?really curious.Jim C--> RV10-List message posted by: "tomhanaway" <tomhanaway(at)comcast.net>Trutrak suggests that a large # of demands on static line may cause lag inauto pilot.  Their suggestion is to run two static lines forward to panelIF this occurs.My current panel is two AFS 4500's, one AFS 3400, 2&1/4" backup altimeterand airspeed, trutrak adi and vsvg2 autopilot , and 430w garmin stack fordemands on static line.Has anyone actually found a need for a second static line (still usingjust  the original two static ports) or is one sufficient?I'd like to avoid second line but if I'm  going to run one, now's thetime.Thanks,Tom H.Read this topic online here:http://forums.matronics.com/viewtopic.php?p 41293#241293   [quote][b]

tomhanaway

Joined: 12 Aug 2006
Posts: 111
Location: Murphy, NC

Posted: Sun Apr 26, 2009 1:29 pm Post subject: Re: Dual static line runs?

Jim, actually in writing. Page 2 of the vsvg2 install manual (see below).  Based on everyone's comments, it sounds like the single line has sufficient volume.  I'm using the safeair 1 system.  

Thanks to all. One more "mental demon" put to rest.

Tom

Pitot and Static Connections

All multi-servo TruTrak autopilots require connections to the pitot and static lines. The preferred method of this connection

would be tee fittings near the aircraftâ€™s altimeter. The static line for the autopilot requires due care in its construction, as

excessive lag or insufficient static orifices can cause the autopilot to oscillate (hunt) in pitch. Although there is compensation

within the autopilot sufficient to handle moderate amounts of lag, the importance of a good static port and line cannot be

overstated. In some cases problems can be caused by having a large number of devices (including the autopilot) connected to a

single, insufficient, static port. In other cases, the static line itself is adequate but there are one or more devices connected to the

same line, one of which has a large static reservoir. A simple remedy for this problem if it occurs is a tee-fitting near the static

port, and a dedicated line to the autopilot only. Obviously, an insufficiently-large orifice coupled with large static reservoirs

can aggravate the problems associated with lag.

jim(at)CombsFive.Com
Guest

Posted: Sun Apr 26, 2009 5:32 pm Post subject: Dual static line runs?

I am currently installing an VSGV DII and missed that statement.  I could see where a older mechanical instrument might have a set of "Bellows" and that by itself could set up some pressure fluctuations.  The newer electronic EFIS units depend on mems based pressure sensors and would not have any such devices.  I have been focusing on the servo installation this weekend.  The connections to the control unit will happen this week.Comment for anyone currently running wiring.  Run ALL the wires you ever think you might need.  Going back and adding them is NOT a fun process.Thanks Tom for the post.Jim CombsN312F Flying (Soon with autopilot!)--> RV10-List message posted by: "tomhanaway" <tomhanaway(at)comcast.net>Jim, actually in writing. Page 2 of the vsvg2 install manual (see below). Based on everyone's comments, it sounds like the single line hassufficient volume.  I'm using the safeair 1 system.Thanks to all. One more "mental demon" put to rest.TomPitot and Static ConnectionsAll multi-servo TruTrak autopilots require connections to the pitot andstatic lines. The preferred method of this connectionwould be tee fittings near the aircraftâ&euro;&trade;s altimeter. The static line forthe autopilot requires due care in its construction, asexcessive lag or insufficient static orifices can cause the autopilot tooscillate (hunt) in pitch. Although there is compensationwithin the autopilot sufficient to handle moderate amounts of lag, theimportance of a good static port and line cannot beoverstated. In some cases problems can be caused by having a large numberof devices (including the autopilot) connected to asingle, insufficient, static port. In other cases, the static line itselfis adequate but there are one or more devices connected to thesame line, one of which has a large static reservoir. A simple remedy forthis problem if it occurs is a tee-fitting near the staticport, and a dedicated line to the autopilot only. Obviously, aninsufficiently-large orifice coupled with large static reservoirscan aggravate the problems associated with lag.Read this topic online here:http://forums.matronics.com/viewtopic.php?p 41355#241355   [quote][b]

wayne.e(at)grandecom.net
Guest

Posted: Mon Apr 27, 2009 3:31 am Post subject: Dual static line runs?

Tom,

  

 I used the Safeair system also and I have the  TruTrak Sorcerer auto pilot and a bunch of other static required  instruments and I've had no problems at  all. I've also had my instruments IFR certified and they found no  problems.

  

 Wayne Edgerton 

 N602WT  flying

    [quote][b]

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