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Exhaust Hanger Broken

Taildrgr

Well Known Member
During my preflight I grab the exhaust extension below the cowl exit and give it a good shake.

At 16 hours into Phase I, my right pipe was loose.

Looking into the cowl exit with a flashlight showed a broken exhaust hanger.

My hangers are connected to the engine sump so the exhaust moves with the engine.

I called Clint at Vetterman Exhaust and he said the hanger tubes can break if they are bent for fitting during installation.
As can be seen in the pics, mine is not bent.
Clint also said they have had some rare breaks for unknown reasons, perhaps a defect in the crimped end.

I think I will move the cross piece up a bit to make sure it does not rub on the nose gear mount.

Anyway, I replaced the hanger tube and will continue checking them during preflight.

Just wanted to give a heads up to all about checking those exhaust hangers.

DSCN1110_zpsbvlfv9ho.jpg


I put the hanger back together for this picture.....
DSCN1106_zpstlkgdaeo.jpg
 
A little jiggle on the exhaust pipes is always a part of my preflight and glad to see others (you) doing it as well.
 
Been a problem for as long as RVs have had exhaust systems

Been flying my RV-6 for 16 years and broken exhaust hangars were a known issue when my plane was new. I carry a length of steel automotive brake line in the flight kit so a new hanger can be fabricated on short notice. Fortunately a broken hangar usually won't keep you from flying the plane home.
 
The components in the exhaust hangar system break frequently. I carry a spare set in my fly-away kit.

That's a good case for installing the bolts in a "backwards" from standard fashion with the nuts facing out.

Would make a replacement easier with less clamping tools involved in the field. :)
 
Hopefully, this won't be a recurring problem every 16 hours, but I did order 2 extra hanger pieces from Clint just in case!

It only took about 20 minutes to change it out.

Good idea to put one in my travel kit for long x-cntry's.
 
I replaced all of my with pieces made out of solid steel. I flattened out the ends of the steel rod and now have a bullet proof system that will never brake.
 
I converted my upright tubing running from the exhaust to the back of the sump to very thick walled 4130 chrome moly - required MAPP gas to heat the ends sufficiently well to pound out flats for the bolts...no breakage in over 450 hours.
 
what about a washer between the hangar and bracket to give it more room to move?
 
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This is a common problem and will come back. I replaced all these hangers with a solid piece of 3/8" aluminum rod. Never had the problem again.

Carl
 
Stressed

what about a washer between the hangar and bracket to give it more room to move?

I'm not sure if it's 'room to move' or a 'slight offset preload' on the "bulge" portion of the hangar.

If you look closely at the first picture it seems like there is mark on the horizontal tab radius where the vertical hanger may have been in contact. This could put a stress on the vertical hanger tab when the assembly is clamped into place.

The final installation of the assembly is on my schedule for today :) and I'll look further, but one solution my be an AN-970-3 washer as a spacer. I would think a large bearing area under the tab would be good.

The only two spots for this contact seem to be the lower ends of the vertical hangers. Have folks had breakages at the other four tab locations?

ADDED

The AN-970-3 washer worked well with a slight chop off one side to ensure it did not touch the edge of the flattened portion.

I had alignment/interference problems in other areas and will post in a new thread...
 
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Hi Gil,
Thanks for your input.

I have already put the new hanger on, but if it breaks again at that spot, I will definitely do something different. Perhaps a washer, but I like the idea of a 3/8 solid aluminum rod.

The exhaust moves mostly side to side as the engine runs, so I can see a fatigue failure is possible where it broke. Especially if the rubber cross piece rubs on the nose wheel mount.
 
Many years ago I saw an RV8 that had the tubes replaced with what looked like a good quality branded ground strap. Seemed like a good idea.
 
I replaced all of my with pieces made out of solid steel. I flattened out the ends of the steel rod and now have a bullet proof system that will never brake.

Turbo,
Where do you get your steel tube for this?
 
Chasing the breaks

I had a rash of hangar breaks the past couple of years. Recently I put an extra strap on the lower side of my stacks, removed all the old Adel clamps and have been trouble freee ever since.

Some pix, keepin' it real.

20151123_150515.jpg


20151123_150509.jpg
 
Does anybody have specs for the exhaust hanger hose handy? I need to replace a couple oily overstretched hoses.
 
Prestone power steering return hose part#PS0308 sold at Autozone, O'Reilly's, Advance Auto Parts, etc, works excellent. It's 3/8" ID, comes in a 2 foot package, and has thick walls and is super oil-resistant.
 
Ours broke too. A mechanic friend from work helped us make our last ones using two drill bits in a vise to make a radius on both sides at the crimp. No issues so far. We do carry a spare in our tool bag.
 
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