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Weak Air Compressor?

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twvandusen

Joined: 20 Sep 2017
Posts: 11
Location: Clark Fork Idaho

Posted: Mon Sep 10, 2018 5:58 pm Post subject: Weak Air Compressor?

After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!

draftsjust417(at)gmail.co
Guest

Posted: Mon Sep 10, 2018 6:12 pm Post subject: Weak Air Compressor?

As an aside, I noticed a similar problem in my CJ6, and discovered 1 of my old landing gear hoses has a small longitudinal rupture that hissed out air beyond what the compressor could make up for.Readily checked and easily fixed, just an idea.

Congrats on certification!

Justin Drafts

N280NC

On Tue, Sep 11, 2018 at 6:28 AM, twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>

 

 After 14 months of working the problem, my NanchangÂ  finally received it's U.S. Airworthiness Certificate.Â  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.Â  The system still leaks some but it may also be a weak air compressor.Â  Is there a way to test the compressor?Â  What are the limits?Â  Thanks everyone!

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=483084#483084

 

 

 

 

 

 

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glipaz

Joined: 11 Jan 2011
Posts: 110

Posted: Mon Sep 10, 2018 11:08 pm Post subject: Re: Weak Air Compressor?

Were you making over 30atm before?   If not then maybe your pressure relief pop off valve needs adjusting and is set too low.  If you were making over 30atm before and are not now then you are likely leaking air in the hard line from the compressor to the snot bottle or the snot bottle itself is leaking air.  The banjo fitting on the compressor can leak.  Try tightening it or replace the crush washers on it and tighten.  If not then the flares on the hard line coming from the compressor might have a small crack and will leak.  If not, then test the fittings on the snot bottle and make sure the valve on the snot bottle is not leaking. If it is the valve then disassemble and clean it or replace it with a swagelock SS valve as has been described here before.

dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 11, 2018 5:47 am Post subject: Weak Air Compressor?

Did you attempt to adjust the pressure relief valve on the firewall (Pop Off Valve) break-over pressure?  It is adjustable.  A "rule of thumb" adjustment is 5 ATM's for each 1/2 turn.  Adjust to 50-55 ATM's.

Dennis

       From: twvandusen <twvandusen(at)gmail.com>

 To: yak-list(at)matronics.com 

 Sent: Monday, September 10, 2018 10:02 PM

 Subject: Yak-List: Weak Air Compressor?

--> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>

After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=483084#483084

http://forums.matronics.com

http:p;                             -Matt Dralle, List Admin.

http://www.matronics.com/contribution

Clouddog

Joined: 02 Jun 2016
Posts: 119
Location: Lebanon, TN

Posted: Tue Sep 11, 2018 6:56 am Post subject: Weak Air Compressor?

Another area to look at is the banjo fitting on the compressor. It has a valve that can carbon up. Suggest you take off the banjo fitting and check and clean the valve. Also when I did mine, I didn't get the crush washer tight enough and had a small leak at the banjo fitting when I reinstalled it. I tightened up the fitting and Wa-la..... air!



Greg Wrobel

On Mon, Sep 10, 2018, 21:04 twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:



 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>

 

 After 14 months of working the problem, my NanchangÂ  finally received it's U.S. Airworthiness Certificate.Â  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.Â  The system still leaks some but it may also be a weak air compressor.Â  Is there a way to test the compressor?Â  What are the limits?Â  Thanks everyone!

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=483084#483084

 

 

 

 

 

 

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dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 11, 2018 7:11 am Post subject: Weak Air Compressor?

Another thing that is easy to do and can make a huge difference on how fast the air tank will charge is to remove the "snot" bottle from the firewall and flush it out completely either with avgas or mineral spirits.  Fill the snot bottle with flushing liquid and shake well.  Flush all three orifices; input, output and drain.  Once you see the flushing liquid run clear out of all 3, dry it out with shop pressure and reinstall.  You'll be amazed how much faster your air bottle (or bottles if you have a CJ) will charge.



Dennis



       From: A. Dennis Savarese <dsavarese0812(at)bellsouth.net>

 To: "yak-list(at)matronics.com" <yak-list(at)matronics.com> 

 Sent: Tuesday, September 11, 2018 9:51 AM

 Subject: Re: Weak Air Compressor?

  

 

Did you attempt to adjust the pressure relief valve on the firewall (Pop Off Valve) break-over pressure?  It is adjustable.  A "rule of thumb" adjustment is 5 ATM's for each 1/2 turn.  Adjust to 50-55 ATM's.

Dennis



       From: twvandusen <twvandusen(at)gmail.com>

 To: yak-list(at)matronics.com 

 Sent: Monday, September 10, 2018 10:02 PM

 Subject: Weak Air Compressor?

  

 

--> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>



After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=483084#483084







http://www.matronics.com/Navigator?Yak-List



http://forums.matronics.com



 http:p;                             -Matt Dralle, List Admin.



http://www.matronics.com/contribution

dsavarese0812(at)bellsout
Guest

Posted: Tue Sep 11, 2018 7:13 am Post subject: Weak Air Compressor?

Excellent point Greg.  Especially about the crush washers.

Dennis

       From: Greg Wrobel <clouddog22(at)gmail.com>

 To: yak-list(at)matronics.com 

 Sent: Tuesday, September 11, 2018 11:00 AM

 Subject: Re: Weak Air Compressor?

Another area to look at is the banjo fitting on the compressor. It has a valve that can carbon up. Suggest you take off the banjo fitting and check and clean the valve. Also when I did mine, I didn't get the crush washer tight enough and had a small leak at the banjo fitting when I reinstalled it. I tightened up the fitting and Wa-la..... air!

Greg Wrobel

On Mon, Sep 10, 2018, 21:04 twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>

 After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=483084#483084

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 List" rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List

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 eferrer noreferrer" target="_blank">http://forums.matronics.com

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dougsappllc(at)gmail.com
Guest

Posted: Tue Sep 11, 2018 8:02 am Post subject: Weak Air Compressor?

Weak compressor:1. Check poppet valve and seat for carbon build up

2. Change out the poppet valve spring for a new one.

3. DO NOT try to reuse the banjo crush washers, order up a set of new.

4. Make 100% sure that your snot valve is fully closed (50% of the time this is the problem)

5. Pressurize the line from snot valve to compressor banjo and check for cracks or leaks

6. Don't think your doing it a favor by squirting WD-40 or MMM into the filter, your not.Â  It will just carbon up the poppet valve.

7. Give me a call and I'll loan you my KY2 compressor test kit.

Good luck,

Doug

Â Â 

On Tue, Sep 11, 2018 at 7:56 AM, Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:

 	  Quote: 	
		  Another area to look at is the banjo fitting on the compressor. It has a valve that can carbon up. Suggest you take off the banjo fitting and check and clean the valve. Also when I did mine, I didn't get the crush washer tight enough and had a small leak at the banjo fitting when I reinstalled it. I tightened up the fitting and Wa-la..... air!



Greg Wrobel

On Mon, Sep 10, 2018, 21:04 twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:



 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>

 

 After 14 months of working the problem, my NanchangÂ  finally received it's U.S. Airworthiness Certificate.Â  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.Â  The system still leaks some but it may also be a weak air compressor.Â  Is there a way to test the compressor?Â  What are the limits?Â  Thanks everyone!

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=483084#483084

 

 

 

 

 

 

 ===========

 List" rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List

 ===========

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 eferrer noreferrer" target="_blank">http://forums.matronics.com

 ===========

 WIKI -

 errer noreferrer" target="_blank">http://wiki.matronics.com

 ===========

 b Site -

 Â  Â  Â  Â  Â  -Matt Dralle, List Admin.

 rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/contribution

 ===========

mark.bitterlich(at)navy.m
Guest

Posted: Tue Sep 11, 2018 1:46 pm Post subject: Weak Air Compressor?

Something that you will use more than once is a hose/line/fittings that allow you to disconnect the line at the compressor and convert to standard AN fitting.  Then use any kind of compressed air, or nitrogen (never oxygen) and pump it up to 700 psi and listen for leaks.  You'll find them.  If you have none, suspect compressor or check valve in the banjo fitting.



________________________________

From: owner-yak-list-server(at)matronics.com [owner-yak-list-server(at)matronics.com] on behalf of A. Dennis Savarese [dsavarese0812(at)bellsouth.net]

Sent: Tuesday, September 11, 2018 9:47 AM

To: yak-list(at)matronics.com

Subject: [Non-DoD Source] Re: Weak Air Compressor?



Did you attempt to adjust the pressure relief valve on the firewall (Pop Off Valve) break-over pressure?  It is adjustable.  A "rule of thumb" adjustment is 5 ATM's for each 1/2 turn.  Adjust to 50-55 ATM's.

Dennis

________________________________

From: twvandusen <twvandusen(at)gmail.com>

To: yak-list(at)matronics.com

Sent: Monday, September 10, 2018 10:02 PM

Subject: Weak Air Compressor?






After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=483084#483084

http://www.matronics.com/Navigator?Yak-List

http://forums.matronics.com

http:p;                             -Matt Dralle, List Admin.

http://www.matronics.com/contribution

k7wx

Joined: 24 May 2010
Posts: 117

Posted: Tue Sep 11, 2018 9:51 pm Post subject: Weak Air Compressor?

Another way to find leaks is to use a hand held ultrasonic leak detector. We have four CJs in one hangar and this piece of equipment is shared by everyone. Itâ€™s capable of uncovering even the smallest leak. And a large leak sounds like a hurricane. Here's an image of what we use. Worth every penny when a pneumatic system starts acting up and the cause is not obvious. These are available on Amazon. 

Warren Hill

N464TW

Mesa, AZ



[img]cid:C95F8384-4E23-4107-B001-7D378A63B489[/img]  	  Quote: 	
		  On Sep 11, 2018, at 7:56 AM, Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:

Another area to look at is the banjo fitting on the compressor. It has a valve that can carbon up. Suggest you take off the banjo fitting and check and clean the valve. Also when I did mine, I didn't get the crush washer tight enough and had a small leak at the banjo fitting when I reinstalled it. I tightened up the fitting and Wa-la..... air!

Greg Wrobel



On Mon, Sep 10, 2018, 21:04 twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>  After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!     Read this topic online here:  http://forums.matronics.com/viewtopic.php?p=483084#483084       =========== List" rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List ===========  FORUMS - eferrer noreferrer" target="_blank">http://forums.matronics.com =========== WIKI - errer noreferrer" target="_blank">http://wiki.matronics.com =========== b Site -           -Matt Dralle, List Admin. rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/contribution ===========

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k7wx

Joined: 24 May 2010
Posts: 117

Posted: Wed Sep 12, 2018 7:13 am Post subject: Weak Air Compressor?

Another way to find leaks is to use a hand held ultrasonic leak detector. We have four CJs in one hangar and this equipment is shared by everyone. Itâ€™s capable of uncovering even the smallest leak. Worth every penny when the pneumatic system is acting up and the cause is not obvious. There are several different models available on Amazon. 

Warren Hill

N464TW

Mesa, AZ



  	  Quote: 	
		  On Sep 11, 2018, at 7:56 AM, Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:

Another area to look at is the banjo fitting on the compressor. It has a valve that can carbon up. Suggest you take off the banjo fitting and check and clean the valve. Also when I did mine, I didn't get the crush washer tight enough and had a small leak at the banjo fitting when I reinstalled it. I tightened up the fitting and Wa-la..... air!

Greg Wrobel



On Mon, Sep 10, 2018, 21:04 twvandusen <twvandusen(at)gmail.com (twvandusen(at)gmail.com)> wrote:

 	  Quote: 	
		  --> Yak-List message posted by: "twvandusen" <twvandusen(at)gmail.com (twvandusen(at)gmail.com)>  After 14 months of working the problem, my Nanchang  finally received it's U.S. Airworthiness Certificate.  We fixed several air leaks in a recent annual inspection but during a recent runup I couldn't achieve the required 30 ATMs for takeoff.  The system still leaks some but it may also be a weak air compressor.  Is there a way to test the compressor?  What are the limits?  Thanks everyone!     Read this topic online here:  http://forums.matronics.com/viewtopic.php?p=483084#483084       =========== List" rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List ===========  FORUMS - eferrer noreferrer" target="_blank">http://forums.matronics.com =========== WIKI - errer noreferrer" target="_blank">http://wiki.matronics.com =========== b Site -           -Matt Dralle, List Admin. rel="noreferrer noreferrer" target="_blank">http://www.matronics.com/contribution ===========

twvandusen

Joined: 20 Sep 2017
Posts: 11
Location: Clark Fork Idaho

Posted: Wed Sep 12, 2018 9:45 am Post subject: Re: Weak Air Compressor?

Thanks everyone for taking the time to help me out.  I'll be home later in the week and will be able to apply some of these ideas to my Nanchang.  I'll keep you all informed of the results.

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