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Jaguar Cowl cabin heat cold air scat line

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bvnj(at)yahoo.com
Guest

Posted: Sat Jul 02, 2011 10:24 am Post subject: Jaguar Cowl cabin heat cold air scat line

Hi Gary,



My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield. 

I don't see where does this 1 inch line connects to now. Where have you been connecting it to?



Thank you,

-Boris

teamgrumman(at)yahoo.com
Guest

Posted: Sat Jul 02, 2011 11:03 am Post subject: Jaguar Cowl cabin heat cold air scat line

Hi Boris, 

I eliminated this for the STC.  Just plug it with a rubber plug.

In 1985, I was doing the first annual on my 77 Cheetah and saw that hose.  It didn't make any sense to me.  So, I removed it.  I never replaced it.  I sold the plane in 1999.  As far as I know, it's still not there.

I also removed it on my Tiger prior to the new cowling.

With the cabin heat coming in under positive pressure, you don't need the hose.  You can install it anyway you want.  Get a 1 inch flanged duct from Aircraft Spruce and mount it under the ignition leads to the right of the oil cooler.  

Gary



From: "bvnj(at)yahoo.com" <bvnj(at)yahoo.com>

To: Teamgrumman <teamgrumman-list(at)matronics.com>

Sent: Sat, July 2, 2011 11:22:05 AM

Subject: Jaguar Cowl cabin heat cold air scat line



   

 [quote][b]

flyv35b(at)minetfiber.com
Guest

Posted: Tue Jul 05, 2011 10:44 am Post subject: Jaguar Cowl cabin heat cold air scat line

The 1" duct does dilute the hot air and reduce the temperature some. 

How much I don't know but Grumman thought they needed it.  The plumbing 

would have been easier without it as it has been somewhat problematic 

securing the Y to the engine mount tubing and keeping the metal air 

outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.



An ideal system will have a mixing valve so that the amount of cold air 

mixing with the hot cabin heat muff air can be regulated.  It's better 

to have a lot of warm air flow rather that a small amount of very hot 

air that burns your feet etc.



Cliff



On 7/2/2011 11:22 AM, bvnj(at)yahoo.com wrote:

 	  Quote: 	
		   



 Hi Gary,



 My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield.

 I don't see where does this 1 inch line connects to now. Where have you been connecting it to?



 Thank you,

 -Boris

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Tue Jul 05, 2011 11:15 am Post subject: Jaguar Cowl cabin heat cold air scat line

Years ago I began experimenting with reducing the size of the fresh air inlet to the muffler. I found that no more than about a half inch diameter hole is all that is needed to maintain cabin heat with OAT even down in the teens F. 

Among several benefits one is that the lower cowl is not pressurized as much as it is with the full size opening. This helps with lowering CHTs, enough to see the difference with the gauges and it also reduces cooling drag and keeps the overflow air at the cabin heat valve from burning things up. It also keeps the exhaust pipes from cooling which keeps velocities up to increase scavenging in the powerflow tuned exhaust

Why pressurize the lower cowl all the time by continuously dumping unneeded really hot air?

Would have been nice if the cabin heat valve were originally placed at the inlet to the muffler. 

Carb heat was unaffected

It is a simple to do for many benefits.....

YMMV

Ned

Sent from my iPhone

On Jul 5, 2011, at 1:41 PM, flyv35b <flyv35b(at)minetfiber.com> wrote:

 	  Quote: 	

 The 1" duct does dilute the hot air and reduce the temperature some. How much I don't know but Grumman thought they needed it.  The plumbing would have been easier without it as it has been somewhat problematic securing the Y to the engine mount tubing and keeping the metal air outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.

 An ideal system will have a mixing valve so that the amount of cold air mixing with the hot cabin heat muff air can be regulated.  It's better to have a lot of warm air flow rather that a small amount of very hot air that burns your feet etc.

 Cliff

 On 7/2/2011 11:22 AM, bvnj(at)yahoo.com wrote:

> 

> 

> Hi Gary,

> 

> My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield.

> I don't see where does this 1 inch line connects to now. Where have you been connecting it to?

> 

> Thank you,

> -Boris

> 

> 

> 

> 

>

teamgrumman(at)yahoo.com
Guest

Posted: Tue Jul 05, 2011 12:44 pm Post subject: Jaguar Cowl cabin heat cold air scat line

With the Jaguar cowling, the fresh air for the muffler is in front of the #1 cylinder.  It's pressurized air flow as opposed to the static air flow on the stock cowling.  An argument could be made that the 1" duct is designed to create airflow through the muffler.

From: flyv35b <flyv35b(at)minetfiber.com>

To: teamgrumman-list(at)matronics.com

Sent: Tue, July 5, 2011 11:41:16 AM

Subject: Re: TeamGrumman-List:  Jaguar Cowl cabin heat cold air scat line

--> TeamGrumman-List message posted by: flyv35b <flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)>

The 1" duct does dilute the hot air and reduce the temperature some. 

How much I don't know but Grumman thought they needed it.  The plumbing 

would have been easier without it as it has been somewhat problematic 

securing the Y to the engine mount tubing and keeping the metal air 

outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.

An ideal system will have a mixing valve so that the amount of cold air 

mixing with the hot cabin heat muff air can be regulated.  It's better 

to have a lot of warm air flow rather that a small amount of very hot 

air that burns your feet etc.

Cliff

On 7/2/2011 11:22 AM,

teamgrumman(at)yahoo.com
Guest

Posted: Tue Jul 05, 2011 12:45 pm Post subject: Jaguar Cowl cabin heat cold air scat line

Thanks for the info Ned.  This means I could significantly reduce the size of the duct in front of #1.

From: 923te <923te(at)att.net>

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

Sent: Tue, July 5, 2011 12:12:23 PM

Subject: Re: Jaguar Cowl cabin heat cold air scat line

--> TeamGrumman-List message posted by: 923te <923te(at)att.net (923te(at)att.net)>

Years ago I began experimenting with reducing the size of the fresh air inlet to the muffler. I found that no more than about a half inch diameter hole is all that is needed to maintain cabin heat with OAT even down in the teens F. 

Among several benefits one is that the lower cowl is not pressurized as much as it is with the full size opening. This helps with lowering CHTs, enough to see the difference with the gauges and it also reduces cooling drag and keeps the overflow air at the cabin heat valve from burning things up. It also keeps the exhaust pipes from cooling which keeps velocities up to increase scavenging in the powerflow tuned exhaust

Why pressurize the lower cowl all the time by continuously dumping unneeded really hot air?

Would have been nice if the cabin heat valve were originally placed at the inlet to the muffler. 

Carb  heat was unaffected

It is a simple to do for many benefits.....

YMMV

Ned

Sent from my iPhone

On Jul 5, 2011, at 1:41 PM, flyv35b <flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)> wrote:

[quote] --> TeamGrumman-List message posted by: flyv35b <flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)>

 The 1" duct does dilute the hot air and reduce the temperature some. How much I don't know but Grumman thought they needed it.  The plumbing would have been easier without it as it has been somewhat problematic securing the Y to the engine mount tubing and keeping the metal air outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.

 An ideal system will have a mixing valve so that the amount of cold air mixing with the hot cabin heat muff air can  be regulated.  It's better to have a lot of warm air flow rather that a small amount of very hot air that burns your feet etc.

 Cliff

 On 7/2/2011 11:22 AM, bvnj(at)yahoo.com (bvnj(at)yahoo.com) wrote:

> -->  TeamGrumman-List message posted by: bvnj(at)yahoo.com (bvnj(at)yahoo.com)

> 

> Hi Gary,

> 

> My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield.

> I don't see where does this 1 inch line connects to now. Where have you been connecting it to?

> 

> Thank you,

> -Boris

>   

  	  Quote: 	
		  [b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Tue Jul 05, 2011 1:45 pm Post subject: Jaguar Cowl cabin heat cold air scat line

I'm not convinced the duct is even needed. Seems to me that the air in the lower cowl is "fresh" enough. It was fresh enough for VW to use in millions of bugs and some Corvairs.  Only smelled bad when the cylinders were either brand new or really old 

I don't get why my PF muffler is  open ended next to the carb heat intake. That just allows mostly lower cowl air for carb heat instead of mostly hot air off the exhaust pipes thru the 'box'

Didn't your test show PF has an issue providing enough heat for the required rise?

[quote] 	  Quote: 	
		  	


[b]

bvnj(at)yahoo.com
Guest

Posted: Wed Jul 06, 2011 9:37 am Post subject: Jaguar Cowl cabin heat cold air scat line

A lot of useful info, thank you!



I guess I might want to try to attach an aluminum strip to the right front baffle and see how much of the cabin heat inlet I can cover and still get the carb heat temp drop.



As for the 1" fresh line, just leave it open into cowl space and use your nose as an additional engine diagnostic tool? 



Q - 1. Gary, if I am not using that 1" line, is there any place I could get a 3" to 2" reducer to put on the PowerFlow cabin heat outlet and get rid of that ugly "Y" altogether? Exhaust section of car parts store? 



Q - 2. I have another contraption in my cabin heat inlet SCAT, called "muffler". It's number 13 on the attached diagram. It was added in '77, I think. What the (at)&^% is that for? 



Thank you,

-Boris

Cabin_Heat.jpg

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teamgrumman(at)yahoo.com
Guest

Posted: Wed Jul 06, 2011 9:51 am Post subject: Jaguar Cowl cabin heat cold air scat line

I know what you mean about the carb heat entrance.  Seems there is enough heat there and that leaving it open improves the airflow to the carb.  I fabricated a plate and did a number of carb heat rise tests.  There was about 2 or 3 degrees difference, higher, with the plate.  Not worth the aggravation.

From: 923te <923te(at)att.net>

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

Sent: Tue, July 5, 2011  2:42:19 PM

Subject: Re: Jaguar Cowl cabin heat cold air scat line

I'm not convinced the duct is even needed. Seems to me that the air in the lower cowl is "fresh" enough. It was fresh enough for VW to use in millions of bugs and some Corvairs.  Only smelled bad when the cylinders were either brand new or really old 

I don't get why my PF muffler is  open ended next to the carb heat intake. That just allows mostly lower cowl air for carb heat instead of mostly hot air off the exhaust pipes thru the 'box'

Didn't your test show PF has an issue providing enough heat for the required rise?

[quote][quote]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Jul 06, 2011 10:34 am Post subject: Jaguar Cowl cabin heat cold air scat line

Boris



I still reduce the air inlet at the muffler while having the Jaguar cowl. 



On another note, the baffles covering the front of the front cylinders can be adjusted to cause CHTs to change. For example, if you find the front cylinders running hotter than the back you can lower the baffle. Take note that very small changes make big changes in cooling. Like 1/16 inch up or down can make large temp changes. 



Gary was interested in me doing some experimenting and he gave me an additional right front baffle. 



I removed the tab covering the cylinder head and made the baffle straight and even. This seemed to be the best solution for the right side baffle in my particular Tiger for lowest CHT and eveness between Cylinders



 my iPhone



On Jul 6, 2011, at 12:34 PM, b v <bvnj(at)yahoo.com> wrote:



 	  Quote: 	
		   A lot of useful info, thank you!

 

 I guess I might want to try to attach an aluminum strip to the right front baffle and see how much of the cabin heat inlet I can cover and still get the carb heat temp drop.

 

 As for the 1" fresh line, just leave it open into cowl space and use your nose as an additional engine diagnostic tool? 

 

 Q - 1. Gary, if I am not using that 1" line, is there any place I could get a 3" to 2" reducer to put on the PowerFlow cabin heat outlet and get rid of that ugly "Y" altogether? Exhaust section of car parts store? 

 

 Q - 2. I have another contraption in my cabin heat inlet SCAT, called "muffler". It's number 13 on the attached diagram. It was added in '77, I think. What the (at)&^% is that for? 

 

 Thank you,

 -Boris

 <Cabin Heat.jpg>

teamgrumman(at)yahoo.com
Guest

Posted: Wed Jul 06, 2011 11:42 am Post subject: Jaguar Cowl cabin heat cold air scat line

You cannot affect carb heat drop.  That is a function of the Power Flow.

Plug the hole in the "Y" divider with a 1 inch rubber plug.  RTV it in place.

A-1:  In 1985, I cut off the 1 inch duct on the "Y" and had a shop weld a piece in place.  After powder coating, it looked pretty good.  Note, the AG5B does not use that 1 inch duct.  Get one of the reducers from Fletchair.

A-2: VERY GOOD QUESTION!  In 1984 when I began the restoration on my first Cheetah, I discovered that too.  At the time, I was told that Grumman-American included that muffler so the pilot could not hear the engine with the cabin heat on.  I removed it and flew for a while.  Then put it back on and flew for a  while.  I couldn't tell any difference.  On a Cheetah, the cabin heat is in the middle of the firewall.  SOOOOO.   I had a piece of aluminum tubing swedged out and used it as a coupler.  I mounted the muffler onto the cabin heat valve with fuel tank sealant.  Years later, on my second Cheetah, I removed the muffler material from the muffler and put the muffler material inside the cabin heat valve.  After that, I just eliminated the damn thing.  

Keep It Simple Stupid.  The good ole KISS principle.

On a side note:  air flow testing showed the cabin heat inlet in front of #1 kept the airflow attached to the inlet better.  Without the cabin heat duct (I call it the vacuum cleaner attachment), there is a big recirculation of airflow in the inner corner.  The same is true on the left inlet in front of #2.  But, the fix for that one is a little  more involved.  

Gary



From: b v <bvnj(at)yahoo.com>

To: Teamgrumman <teamgrumman-list(at)matronics.com>

Sent: Wed, July 6, 2011 10:34:35 AM

Subject: Re: Jaguar Cowl cabin heat cold air scat line



 A lot of useful info, thank you!



I guess I might want to try to attach an aluminum strip to the right front baffle and see how much of the cabin heat inlet I can cover and still get the carb heat temp drop.



As for the 1" fresh line, just leave it open into cowl space and use your nose as an  additional engine diagnostic tool? 



Q - 1. Gary, if I am not using that 1" line, is there any place I could get a 3" to 2" reducer to put on the PowerFlow cabin heat outlet and get rid of that ugly "Y" altogether? Exhaust section of car parts store? 



Q - 2. I have another contraption in my cabin heat inlet SCAT, called "muffler". It's number 13 on the attached diagram. It was added in '77, I think. What the (at)&^% is that for? 



Thank you,

-Boris

   

 [quote][b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Jul 06, 2011 12:11 pm Post subject: Jaguar Cowl cabin heat cold air scat line

That's interesting, only 2 or 3 deg difference in carb heat rise.  Is that static on the ground or flying?

I have a temp probe in front of the carb air intake behind cyl #3. I was trying to see where LoPresti gets that there is really hot air off cylinders going into the carb. I didn't find any hot air there while flying.  It was about same as my OAT gauge. I could only get a higher reading after being stationary on ground at idle for 10 minutes last summer.  I think it got about 15 deg hotter than OAT



Sent from my iPhone



On Jul 6, 2011, at 12:49 PM, Gary Vogt <teamgrumman(at)yahoo.com (teamgrumman(at)yahoo.com)> wrote:



 	  Quote: 	
		  I know what you mean about the carb heat entrance.  Seems there is enough heat there and that leaving it open improves the airflow to the carb.  I fabricated a plate and did a number of carb heat rise tests.  There was about 2 or 3 degrees difference, higher, with the plate.  Not worth the aggravation.

 	  Quote: 	
		   	  Quote: 	
		   	  Quote:

teamgrumman(at)yahoo.com
Guest

Posted: Wed Jul 06, 2011 12:52 pm Post subject: Jaguar Cowl cabin heat cold air scat line

I did that test in 2000.  Only, I tested the temp of the air going into the oil cooler.  Very little if any radiant heat from the cylinders.

I did the carb heat rise tests in flight as part of the FAA testing.

From: 923te <923te(at)att.net>

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

Sent: Wed, July 6, 2011 1:09:12 PM

Subject: Re:  Jaguar Cowl cabin heat cold air scat line

 That's interesting, only 2 or 3 deg difference in carb heat rise.  Is that static on the ground or flying?

I have a temp probe in front of the carb air intake behind cyl #3. I was trying to see where LoPresti gets that there is really hot air off cylinders going into the carb. I didn't find any hot air there while flying.  It was about same as my OAT gauge. I could only get a higher reading after being stationary on ground at idle for 10 minutes last summer.  I think it got about 15 deg hotter than OAT

Sent from my iPhone

On Jul 6, 2011, at 12:49 PM, Gary Vogt <teamgrumman(at)yahoo.com (teamgrumman(at)yahoo.com)> wrote:

 	  Quote: 	
		  I know what you mean about the carb heat  entrance.  Seems there is enough heat there and that leaving it open improves the airflow to the carb.  I fabricated a plate and did a number of carb heat rise tests.  There was about 2 or 3 degrees difference, higher, with the plate.  Not worth the aggravation.

 	  Quote: 	
		   	  Quote: 	
		   	  Quote: 	

 [quote][b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Jul 06, 2011 12:58 pm Post subject: Jaguar Cowl cabin heat cold air scat line

Remember the cabin heat valve? It is always open to the lower cowl unless cabin heat is fully opened. That's why you sometimes see evidence of heat on the firewall at the bottom of the cabin heat valve where the opening is. There is a lot if air moving thru there and it is very hot. 

Sent from my iPhone

On Jul 6, 2011, at 3:45 PM, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

[quote]Ned:

I am lost... Why would reducing the SCAT tube diameter to the muffler reduce the lower cowl pressure?  It is sealed going to the muffler and sealed from the muffler to the cabin.

 Am I missing something?

Barry

On Tue, Jul 5, 2011 at 3:12 PM, 923te <[url=mailto:923te(at)att.net]923te(at)att.net (923te(at)att.net)[/url]> wrote:

 	  Quote: 	
		   --> TeamGrumman-List message posted by: 923te <[url=mailto:923te(at)att.net]923te(at)att.net (923te(at)att.net)[/url]>

 Years ago I began experimenting with reducing the size of the fresh air inlet to the muffler. I found that no more than about a half inch diameter hole is all that is needed to maintain cabin heat with OAT even down in the teens F.

 Among several benefits one is that the lower cowl is not pressurized as much as it is with the full size opening. This helps with lowering CHTs, enough to see the difference with the gauges and it also reduces cooling drag and keeps the overflow air at the cabin heat valve from burning things up. It also keeps the exhaust pipes from cooling which keeps velocities up to increase scavenging in the powerflow tuned exhaust

 Why pressurize the lower cowl all the time by continuously dumping unneeded really hot air?

 Would have been nice if the cabin heat valve were originally placed at the inlet to the muffler.

 Carb heat was unaffected

 It is a simple to do for many benefits.....

 YMMV

 Ned

 Sent from my iPhone

 On Jul 5, 2011, at 1:41 PM, flyv35b <[url=mailto:flyv35b(at)minetfiber.com]flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)[/url]> wrote:

 > --> TeamGrumman-List message posted by: flyv35b <[url=mailto:flyv35b(at)minetfiber.com]flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)[/url]>

 >

 > The 1" duct does dilute the hot air and reduce the temperature some. How much I don't know but Grumman thought they needed it.  The plumbing would have been easier without it as it has been somewhat problematic securing the Y to the engine mount tubing and keeping the metal air outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.

  >

 > An ideal system will have a mixing valve so that the amount of cold air mixing with the hot cabin heat muff air can be regulated.  It's better to have a lot of warm air flow rather that a small amount of very hot air that burns your feet etc.

  >

 > Cliff

 >

 > On 7/2/2011 11:22 AM, [url=mailto:bvnj(at)yahoo.com]bvnj(at)yahoo.com (bvnj(at)yahoo.com)[/url] wrote:

 >> -->  TeamGrumman-List message posted by: [url=mailto:bvnj(at)yahoo.com]bvnj(at)yahoo.com (bvnj(at)yahoo.com)[/url]

 >>

 >> Hi Gary,

 >>

 >> My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield.

  >> I don't see where does this 1 inch line connects to now. Where have you been connecting it to?

 >>

 >> Thank you,

 >> -Boris

 >>

 >>

 >>

 >>

 >>

 >

 >

 >

 >

 ===========

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

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

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[b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Jul 06, 2011 1:00 pm Post subject: Jaguar Cowl cabin heat cold air scat line

I didn't reduce the scat tube diameter. I put a plate over the muffler opening and drilled a hole in the middle of it. 

Sent from my iPhone

On Jul 6, 2011, at 3:45 PM, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

[quote]Ned:

I am lost... Why would reducing the SCAT tube diameter to the muffler reduce the lower cowl pressure?  It is sealed going to the muffler and sealed from the muffler to the cabin.

 Am I missing something?

Barry

On Tue, Jul 5, 2011 at 3:12 PM, 923te <[url=mailto:923te(at)att.net]923te(at)att.net (923te(at)att.net)[/url]> wrote:

 	  Quote: 	
		   --> TeamGrumman-List message posted by: 923te <[url=mailto:923te(at)att.net]923te(at)att.net (923te(at)att.net)[/url]>

 Years ago I began experimenting with reducing the size of the fresh air inlet to the muffler. I found that no more than about a half inch diameter hole is all that is needed to maintain cabin heat with OAT even down in the teens F.

 Among several benefits one is that the lower cowl is not pressurized as much as it is with the full size opening. This helps with lowering CHTs, enough to see the difference with the gauges and it also reduces cooling drag and keeps the overflow air at the cabin heat valve from burning things up. It also keeps the exhaust pipes from cooling which keeps velocities up to increase scavenging in the powerflow tuned exhaust

 Why pressurize the lower cowl all the time by continuously dumping unneeded really hot air?

 Would have been nice if the cabin heat valve were originally placed at the inlet to the muffler.

 Carb heat was unaffected

 It is a simple to do for many benefits.....

 YMMV

 Ned

 Sent from my iPhone

 On Jul 5, 2011, at 1:41 PM, flyv35b <[url=mailto:flyv35b(at)minetfiber.com]flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)[/url]> wrote:

 > --> TeamGrumman-List message posted by: flyv35b <[url=mailto:flyv35b(at)minetfiber.com]flyv35b(at)minetfiber.com (flyv35b(at)minetfiber.com)[/url]>

 >

 > The 1" duct does dilute the hot air and reduce the temperature some. How much I don't know but Grumman thought they needed it.  The plumbing would have been easier without it as it has been somewhat problematic securing the Y to the engine mount tubing and keeping the metal air outlet duct flange (78/79 Tigers) from sawing into the Y inlet SCAT duct.

  >

 > An ideal system will have a mixing valve so that the amount of cold air mixing with the hot cabin heat muff air can be regulated.  It's better to have a lot of warm air flow rather that a small amount of very hot air that burns your feet etc.

  >

 > Cliff

 >

 > On 7/2/2011 11:22 AM, [url=mailto:bvnj(at)yahoo.com]bvnj(at)yahoo.com (bvnj(at)yahoo.com)[/url] wrote:

 >> -->  TeamGrumman-List message posted by: [url=mailto:bvnj(at)yahoo.com]bvnj(at)yahoo.com (bvnj(at)yahoo.com)[/url]

 >>

 >> Hi Gary,

 >>

 >> My cabin heat scat tube has a splitter. 3 inch line goes to exhaust pipe shroud and a 1inch line used to go to nose bowl diaphragm to supply fresh air. Do you know what it is for? My guess is that without it the hot air is too hot and it could damage the plastic defroster vents and maybe even windshield.

  >> I don't see where does this 1 inch line connects to now. Where have you been connecting it to?

 >>

 >> Thank you,

 >> -Boris

 >>

 >>

 >>

 >>

 >>

 >

 >

 >

 >

 ===========

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

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========

[b]

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Jul 06, 2011 5:32 pm Post subject: Jaguar Cowl cabin heat cold air scat line

Yes and lower the pressure min the lower  cowl if you have the OEM muffler.

 Not if you have the PowerFlow muffler as it is  open ended to the lower cowl.

 Also, I question whether the cabin heat valve  could with stand the pressure and heat with the vavle body being sealed. It  might allow hot air into the cabin all the time if it were  pressurized

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