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Yak-52 Exhaust Danger

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Mozam

Joined: 24 Nov 2006
Posts: 85

Posted: Sat Aug 23, 2008 2:42 pm Post subject: Yak-52 Exhaust Danger

I finally got around to taking a picture to show what all -52 drivers need to be aware of.



The inner pipe of the exhaust section which contains the baffling and shroud for the cockpit heat split open.  You cannot see this split because it is hidden inside the heat shroud.  If you remove this section and inspect the inside of the inner pipe you may see any splits.



When this pipe fails you are getting CO pumped directly into the cockpit via the cockpit air vent system.  And you have no way of knowing this is happening.  I have no idea how long this pipe had been split and I was getting so much CO.  The split in my pipe grew until I finally realized something was amiss when the air from the vent between my knees was so hot it was burning my legs.  Raw HOT exhaust was being pumped straight into the cockpit.



In the pictures you can see what this section looks like with the heat shroud cut off.  You can see the small sections of U-channel that hold the shroud away from the inner pipe.  They are spot welded on and many of the spot welds have failed, leaving more holes in the pipe.  You can even see a new hole I found when I took the picture.  You cannot see the BIG patch on the back side of the pipe.



I STRONGLY recommend that you remove this section of exhaust and inspect the inner pipe for any leaks.



You can see in the picture the new air supply hose I rigged up...works great, but no heat now.



Does anyone have just this section of the exhaust available?



Fly Safe,

Steve Dalton

Exhaust1.jpg

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This is what you cannot see until you cut the heat shroud off.

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randmyak52(at)bellsouth.n
Guest

Posted: Sat Aug 23, 2008 3:54 pm Post subject: Yak-52 Exhaust Danger

Thanks Steve for this important information, YAK owners, standard and TW's 

take note of this information. I have a digital meter that I plug in 

occasionally to check for gas. I have not to date found a high level except 

while doing run-up. Then only with the canopy partially closed. However 

lately on start-up at times I will get oil smoke through the heat duct. As 

the TW owners know at times due to oil passing the exhaust valve  on the 

number one cylinder , oil will run down the exhaust on the right side. This 

causes oil to blow out of the exhaust on start-up. After seeing these Pics, 

I now believe I have a failure under the shroud such as seen in the Pics. 

Due to oil actually entering the heat duct. Guys with winter coming on we 

will be operating more with the canopy closed. Check for gas with an 

instrument and check the system. You can bet I will be checking ASAP.



                                                                             

                                                                             

Lefty



From: "Mozam" <sdalton(at)hughes.net>

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

Sent: Saturday, August 23, 2008 5:42 PM

Subject: Yak-52 Exhaust Danger

 	  Quote: 	
		   



 I finally got around to taking a picture to show what all -52 drivers need 

 to be aware of.



 The inner pipe of the exhaust section which contains the baffling and 

 shroud for the cockpit heat split open.  You cannot see this split because 

 it is hidden inside the heat shroud.  If you remove this section and 

 inspect the inside of the inner pipe you may see any splits.



 When this pipe fails you are getting CO pumped directly into the cockpit 

 via the cockpit air vent system.  And you have no way of knowing this is 

 happening.  I have no idea how long this pipe had been split and I was 

 getting so much CO.  The split in my pipe grew until I finally realized 

 something was amiss when the air from the vent between my knees was so hot 

 it was burning my legs.  Raw HOT exhaust was being pumped straight into 

 the cockpit.



 In the pictures you can see what this section looks like with the heat 

 shroud cut off.  You can see the small sections of U-channel that hold the 

 shroud away from the inner pipe.  They are spot welded on and many of the 

 spot welds have failed, leaving more holes in the pipe.  You can even see 

 a new hole I found when I took the picture.  You cannot see the BIG patch 

 on the back side of the pipe.



 I STRONGLY recommend that you remove this section of exhaust and inspect 

 the inner pipe for any leaks.



 You can see in the picture the new air supply hose I rigged up...works 

 great, but no heat now.



 Does anyone have just this section of the exhaust available?



 Fly Safe,

 Steve Dalton





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 0150#200150





 Attachments:



 http://forums.matronics.com//files/exhaust1_581.jpg



 -- 

 Checked by AVG.

 6:32 PM

dougsappllc(at)gmail.com
Guest

Posted: Sat Aug 23, 2008 4:22 pm Post subject: Yak-52 Exhaust Danger

Steve,

 I do believe I have this Yak 52 cabin heat section in my stock, give me a call on Monday.

  

 Also,  Not saying that it has not been getting done, and not looking to piss anyone off, but it is nearly a law written in stone that the shrouds come off of all cabin heat muffs at every annual, just to prevent what you are describing.  

   

  

 



 

 On Sat, Aug 23, 2008 at 3:42 PM, Mozam <sdalton(at)hughes.net (sdalton(at)hughes.net)> wrote:

 [quote]--> Yak-List message posted by: "Mozam" <sdalton(at)hughes.net (sdalton(at)hughes.net)>

 

I finally got around to taking a picture to show what all -52 drivers need to be aware of.



The inner pipe of the exhaust section which contains the baffling and shroud for the cockpit heat split open.  You cannot see this split because it is hidden inside the heat shroud.  If you remove this section and inspect the inside of the inner pipe you may see any splits.

 

When this pipe fails you are getting CO pumped directly into the cockpit via the cockpit air vent system.  And you have no way of knowing this is happening.  I have no idea how long this pipe had been split and I was getting so much CO.  The split in my pipe grew until I finally realized something was amiss when the air from the vent between my knees was so hot it was burning my legs.  Raw HOT exhaust was being pumped straight into the cockpit.

 

In the pictures you can see what this section looks like with the heat shroud cut off.  You can see the small sections of U-channel that hold the shroud away from the inner pipe.  They are spot welded on and many of the spot welds have failed, leaving more holes in the pipe.  You can even see a new hole I found when I took the picture.  You cannot see the BIG patch on the back side of the pipe.

 

I STRONGLY recommend that you remove this section of exhaust and inspect the inner pipe for any leaks.



You can see in the picture the new air supply hose I rigged up...works great, but no heat now.



Does anyone have just this section of the exhaust available?

 

Fly Safe,

Steve Dalton





Read this topic online here:



[url=http://forums.matronics.com/viewtopic.php?p 0150#200150]http://forums.matronics.com/viewtopic.php?p 0150#200150[/url]

  [quote][b]

randmyak52(at)bellsouth.n
Guest

Posted: Sat Aug 23, 2008 4:37 pm Post subject: Yak-52 Exhaust Danger

That is good information and indicates the need for  sharing information such as this. I have some 2,500 Hrs in both the standard and  TW YAKs, and have yet to pull one for inspection. Indicates that this a learning  business. 

 After some fourteen years of flying these things, I  should have known better, and you can bet I am not pissed off to hear about it.  Everyone should take this information and go with it. Also it would be  interesting to have feed back from all owners that find problems.

  

  

                                                                                                                                                          Lefty

 [quote]   ---

wlannon(at)persona.ca
Guest

Posted: Sat Aug 23, 2008 6:03 pm Post subject: Yak-52 Exhaust Danger

In Canada it is an Airworthiness Directive that  applies to all aircraft regardless of certification status.

  

 Walt

 [quote]   ---

Mozam

Joined: 24 Nov 2006
Posts: 85

Posted: Sat Aug 23, 2008 6:19 pm Post subject: Re: Yak-52 Exhaust Danger

 	  dougsappllc(at)gmail.com wrote: 	
		  Steve,

 I do believe I have this Yak 52 cabin heat section in my stock, give me a call on Monday.

  

 Also,  Not saying that it has not been getting done, and not looking to piss anyone off, but it is nearly a law written in stone that the shrouds come off of all cabin heat muffs at every annual, just to prevent what you are describing.  

   

 

	




Doug,



I will call you...thanks.



How do you remove this shroud for inspection?  It is all welded together and has to be cut off for inspection.



-Steve

viperdoc(at)mindspring.co
Guest

Posted: Sat Aug 23, 2008 6:56 pm Post subject: Yak-52 Exhaust Danger

Mozam,

Thanks for the heads up.

Have you thought about scavenging air off the back of your oil cooler. It

can be done with the 50. The 50 does not have a heat shroud at all yet with

the  air that bleeds into the cockpit from the oil cooler with the door

closed or cracked the 50 stays warm even in 20 degree weather. My oil cooler

is farther forward on the nose than yours in the 52 TW. I'm less likely to

get exhaust gas vented into the cockpit from there. It gets in around the

opening at the tail wheel. Yes I have measured the CO concentration at the

tail. It averages 50 to 60 ppm in the aft empennage during taxi and TO. 

 

doc



--

randmyak52(at)bellsouth.n
Guest

Posted: Sun Aug 24, 2008 5:25 am Post subject: Yak-52 Exhaust Danger

A question I should have asked, another reason to have the detector 

available for spot checks, or perhaps a Perm. installation. One has no way 

of detecting just when the failure occures. An internal visual can be done 

by use of a light and mirror I suppose. This should expose anything but a 

crack. This of course would open as the exhaust expands from heat.

---

viperdoc(at)mindspring.co
Guest

Posted: Sun Aug 24, 2008 7:02 am Post subject: Yak-52 Exhaust Danger

Mozam,

Is it possible to scavenge warm air from the top of the inspection plate on

your oil cooler. The 50 does not have a heat shroud on its 2nd section of

the exhaust on the right bank. It gets so warm inside the pit of the 50

since there is an opening at the top of my oil cooler that I had to install

an insulation blanket on the top of the cooler. It did not seem to make much

difference in the amount of CO getting into the nose by doing that though.

My cooler is mounted farther forward than the ones on the TW. My exhaust

vents parallel to the cooler not in front of the cooler like the TW's. Tim

Williams installed fins on his cooler to vent the hot exhaust away from the

cooler as I remember. 

I suppose exhaust stack extensions could solve the problem too.

Anyway, if you could capture the heat off the cooler then you would not have

to reinstall the shroud.

Install a Scuba system with a stage I - II regulator connected to mil spec

O2 hose that terminates on a CRU-60 for fresh none pollute air with CO. Then

you could hook up and use that old MBU-12 Aviator's Mask you have lying

around from your glory days. Of course, you would have to get a pre-amp for

your Mil spec mic. Know where to acquire that too.

Then you do not need to worry about the concentration of CO in your pit. It

is absorbed by inhalation not by osmosis (skin contact). The problem is

having to refill or swap the tank at the end of a couple of sorties. You do

not need to breath the compressed air once airborne so you can get a couple

of sorties out of a 3500 psi fill. Or you can invest in two stage I's and

make a refill manifold. Then you could refill the tank without removing it

from the A/C.

One could also invest in a diluter demand regulator and install a LOX tank.

Problem there is the expense and the fact that you would need to maintain a

closed circuit so you would have to breath 100% O2 continuously during

start, taxi, TO, hi Alpha maneuvers, landing, taxi in, run-up and shutdown.

Otherwise drop the mask or loosen it to the end clip on the bayonet and

breath around it.

Now there is nothing wrong with breathing 100% O2 for an hour or so except

you have to remember to clear your ears frequently after such a flight to

altitude otherwise you could awaken the next morning with an ear ache from a

serous otitis. 

Just a thought fresh air vs LOX and CO inhalation from TU heating shrouds.

Doc 



--

Mozam

Joined: 24 Nov 2006
Posts: 85

Posted: Sun Aug 24, 2008 9:48 am Post subject: Re: Yak-52 Exhaust Danger

Doc,



My O2 mask wearing days are over.  If I have to get a mask to fly my Yak, it's gone.  



I only need heat in the dead of winter while cruising at altitude and the standard -52 system works just fine for that.  I don't want to engineer a whole new system to replace one that works fine.



However, like many other systems in our planes it must be inspected to insure it is working properly...lest it bite you.  And inspecting this section of exhaust can only be done by removing it and looking closely for any cracks inside the inner most pipe.



I suspect my -52 isn't the only one that has not had such an inspection done in a while...if ever.  I also suspect there are other -52's out there right now with cracked pipes that are pumping CO into the cockpit.  What are the odds that only one -52 in the world (mine) had an exhaust crack in that section of pipe? 



Fly safe,

Steve

viperdoc(at)mindspring.co
Guest

Posted: Sun Aug 24, 2008 10:31 am Post subject: Yak-52 Exhaust Danger

Mozam,

Copy. Seeing how you seem to love your YAK as much I love mine I don't think you'll be parting with her anytime soon.

They'll be prying my stick from my cold hand!

How old was you exhaust system. Mine is 5 years old. We had it off 2 years ago to change an engine. It still looks new especially since I'm putting about 35 hours on her a year now. (Flying the 50 much more than the 52 is why). 

Check with Steve Culp (at) 318-222-0850. If that does not work let me know, I have another number for him too. Last I knew he still had some exhaust parts/ spare sections for the 52.

Wonder how the Trantula System on TJ's 50 is holding up. Understand the tuned pipe system for the CJ was not hacking it. Something about a harmonic in the pipes causing them to crack and break. One of the CJ's at Alabaster in Birmingham, Al had that system with the problem  of the stacks cracking and breaking. One broke in flight. Lucky. No fire.

And off thought. Not getting to fly today secondary to some slow moving bitch named FAY. Why do they always start with the Tornado warnings at 02:00? 

Doc

--

Mozam

Joined: 24 Nov 2006
Posts: 85

Posted: Sun Aug 24, 2008 10:58 am Post subject: Re: Yak-52 Exhaust Danger

Doc,



My exhaust is original, installed at factory in 2001.  It has about 600 hours on it.



Keep in mind, you cannot see the cracks/holes in this section of exhaust while installed on the plane.  On the outside it looked like new...but the inside was totally rotted out!  Be careful out there.



-Steve

dougsappllc(at)gmail.com
Guest

Posted: Sun Aug 24, 2008 2:24 pm Post subject: Yak-52 Exhaust Danger

viperdoc(at)mindspring.co
Guest

Posted: Sun Aug 24, 2008 4:59 pm Post subject: Yak-52 Exhaust Danger

Mozam,

Copy. Will bore scope the stack.

Doc



--

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