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Video Camera Inside Cowling


markejackson02

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Just now, Raptor05121 said:

I get a rise in temps when I fully close mine. I have to have them trail a bit open for the best cooling.

I doubt you'll see much with a camera somehow fastened inside there, and not block airflow at the same time.

I was thinking to put it on the firewall as high up as I could.

This behavior is new, temps used to climb a little before when the flaps were closed but now they all rocket higher.  Just did a bunch of work on the engine so thinking something didn't go back on properly.

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You can usually tell by a flashlight in the accessory compartment- look for light in the front shining from the back.  Feel whether your baffles feel sturdy and whether they sit up flush along the top of the cowl cover.  Those two things alone should be enough to indicate whether you will have a seal problem in flight. You should need to really push the flaps back with a lot of force with your hand to be able to flip them backwards.  

Look at the baffle seals along the front of the engine too.  They are important to make sure air pressure differential favors flow over the cylinder fins.  

 

Also- i don’t see your model year. If manual cowl flaps set the closed position to trail slightly - about a quarter inch or so - not fully closed / sealed in the closed position.  This results in much better air flow.  

Recent work: ensure you don’t have a fuel delivery or spark delivery problem on that side. What did you do to the engine? Do you have an engine monitor with data?  Something changed.  Go where the doctors have been first.  

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Using a device to observe something, but the device itself, causes a disturbance in what you are measuring... reference to Schrödinger's cat in the trunk...

Many people have run into the heat challenge after maintenance...  seals get old and flop out of position...or just don't seal properly anymore...

We have a seal guy around here, if your seals prove to be less than worthy.... @GEE-BEE

PP thoughts only, not a mechanic...

Best regards,

-a-

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4 hours ago, bradp said:

You can usually tell by a flashlight in the accessory compartment- look for light in the front shining from the back.  Feel whether your baffles feel sturdy and whether they sit up flush along the top of the cowl cover.  Those two things alone should be enough to indicate whether you will have a seal problem in flight. You should need to really push the flaps back with a lot of force with your hand to be able to flip them backwards.  

Look at the baffle seals along the front of the engine too.  They are important to make sure air pressure differential favors flow over the cylinder fins.  

 

Also- i don’t see your model year. If manual cowl flaps set the closed position to trail slightly - about a quarter inch or so - not fully closed / sealed in the closed position.  This results in much better air flow.  

Recent work: ensure you don’t have a fuel delivery or spark delivery problem on that side. What did you do to the engine? Do you have an engine monitor with data?  Something changed.  Go where the doctors have been first.  

This is how I found that the seal at the top in the back of my doghouse needed to be replaced. I put a shop light back by the oil filter and looked in from the front. The gaps and holes were easy to see. This is what they looked like before.

1501034438325.thumb.jpg.b92fb3767b65e6a751ae9f81be265faf.jpg1501034467754.thumb.jpg.eb62e4520e2b7b37eb33d32c08bbe3c1.jpg

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I had the mag overhauled, new starter installed.

Cooling has always been an issue albeit a manageable one until now.  I have never had problems with the #3 cylinder until now.  Was always #4 causing issues.

I do have an Insight unit and will try to see if the ignition is causing some issues.  At first glance on the 15 minute test flight, there was nothing apparent.

The baffles are all okay looking while sitting on the ground.

 

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One of the J models at our field was having cooling issues on one side and found the small metal deflector plate between the cylinders had fallen into the bottom cowl. Might be something to check.

Looking at the engine monitor data is a good place to start, but contained to a single side sounds as if it is more physical in relation to airflow, IMO. But whatever the problem is, it needs addressing as 450 degree CHTs do not help cylinders last a long time.

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I'm not sure what the legality of this is, but if I were to do something like this, I would get one of those $30 wifi borescopes from Amazon that links to your phone and snake it and cable tie the box far from the heat of the engine as I wouldn't want the battery to get hot and burst into flames. 

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Come at this from a different angle.  There are a couple of minor bends in the baffles up against the top of the cowling.  I can see them when the cowling is on.

Is there a way to fix these?  The material is bent this way.  Anything to be done short of replacing all the silicone material?

Forgive my crude drawing.

 

baffle.png

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29 minutes ago, markejackson02 said:

Come at this from a different angle.  There are a couple of minor bends in the baffles up against the top of the cowling.  I can see them when the cowling is on.

Is there a way to fix these?  The material is bent this way.  Anything to be done short of replacing all the silicone material?

Forgive my crude drawing.

 

baffle.png

You could cut a dart (little triangle) out of the material so it will lay flat.

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1 hour ago, markejackson02 said:

I tried that on one of the kinks.  Cut a slit and stop drilled the end but it didn't affect anything.

How often does baffling have to be replaced?

I don't think there is any set calendar time or number of hours. I have seen plenty of 50 year old planes that still had the factory baffle seals. If it isn't doing its job then replace it. The material isn't expensive and replaceing it it isn't that hard.

Edited by N201MKTurbo
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After a kink has been in the baffle material for a while, it is tough to get it to flatten back out.  I would seriously consider replacing that strip that is bad (if all the others seem OK), or all of them it there is much doubt. In aviation terms, the material is dirt cheap. Even in real life terms it is not too expensive.

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Not sayin this is your problem but this happened to me so i thought id spit it out. When doing maintenance or just watching mechanics or spectators in the shop you will often see folks leaning over the engine and mashing down on the baffle seal with their arms. Not intentionally,  just lazing around chatting but leaning over engine and bending the seals down can cause them to become less stiff and not seal against cowling. I have had this happen to mine by my own negligence. Now if i see someone leaning on my baffle seals i kindly tell them to lean on something else. Heck i have to think about not doing it myself, its natural to lean on the things. Anyhow just a little something to be on the look out for.

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My one takeaway after reading through these threads is that of incredulous. I find it incredible that a simple piece of rubber is so critical to the operation of our engines and that the precise installation and placement of that rubber dictates its efficiency, let alone someone leaning on it while the cowl is off resulting in a rise of CHT by 20 degrees. Truly a design from a bygone era.

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Just now, M20Doc said:

Baffles and the seals are the equivalent the radiator on your car.  You would not drive your car with a hole in the radiator, you shouldn’t fly your plane with poor baffle seals.

Clarence

True, but if one or two of the fins on the radiator are bent, the temp doesn't go through the roof.

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Just now, flyboy0681 said:

True, but if one or two of the fins on the radiator are bent, the temp doesn't go through the roof.

Exactly, liquid cooling is more efficient than air cooling hence the need for closer attention to better fit and proper maintenance of baffles and seal.  In the times before modern engine monitors, ignorance was bliss.

Clarence

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