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Radiator Hose / Exhaust Spring Interference

Tacco

Well Known Member
How is your lower radiator hose to exhaust spring clearance on the right side? Mine is too close for comfort. Temporary added a "shield" consisting of a cork and aluminum. After a few hours of flight time, the spring is definitely contacting the aluminum. See pic. Have I mis-routed the hose, or fuel line for that matter (it's in the same area)? Baseline RV-12 912 ULS

https://photos.app.goo.gl/Yba9a4z3w94QJBhQ6
 
I can't view your photo. In any event, there is no radiator hose on the right side of the engine. Radiator, and associated hoses, are on left side of engine. Perhaps you mean oil hose that routes between exhaust stacks on right side of engine?
 
Wish I could figure out this photo thing! Worth a thousand words.

It?s the lower radiator hose where it loops back to the aft engine connection. The spring is the aft-most spring on the right side.
 
I can see your picture on Google's website, but I can not get your picture to
post here either. The problem might be at Google's end. Try storing your
picture on some other website, maybe ShutterFly.
 
This is just a test to see if I can successfully post the photo...
AF1QipM4RG2jzD7hYcA6fW2p8fzZSrxcXUIIh_B8sBUv

Ok; didn't work for me either. Hmmm...
 
So long as there is at least 1/4" of space the spring won't hurt the hose. I would however put a heat shield on the hose if it is in close proximity of the exhaust pipe. You can take a 4" - 6" piece of fire sleeve and split it lengthwise. Then place this over the hose between the exhaust pipe and hose. This works very well. You can use just plain plastic wire ties to keep it in place. 3-4 ties depending on how long it is. So long as there is an air gap you should be good to go. Exhaust springs should be safety wired as per Rotax Service Bulletins and the Installation Manual to help prevent them from leaving the plane if they break and springs do break. I was told a long time ago not to fill springs with silicone because it causes them to retain heat and causes them to fail by losing strength or breaking. I believe this was mid 1990's application. You can cut a huge amount of radiated and convected heat down by wrapping your exhaust. This cuts down on under the cowl temps and heat applied to wires and hoses and parts like the VR. This was taught in the Rotax classes.


https://www.rotax-owner.com/en/rota...-new-technique-in-exhaust-spring-installation
 
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You can cut a huge amount of radiated and convected heat down by wrapping your exhaust. This cuts down on under the cowl temps and heat applied to wires and hoses and parts like the VR. This was taught in the Rotax classes.

But do not follow Rogers advice and expect to get an E-LSA airworthiness or any warranty replacement for a failed exhaust system.
 
As a former hot rod builder, I?ve seen enough embrittled and cracked exhaust pipes from wrapping that I?d be reluctant to even use the approach on an airplane.

My issue / concern was not heat. It was contact between the spring and the hose.
 
I wrap my right front exhaust pipe because I do not like the oil hose passing through the exhaust elbow. I've never heard of a strap hanger for the hose failing but it could happen, and if it did, the oil hose would sit directly on the hot exhaust.

That said, I re-wrapped the right front exhaust during last condition inspection and exhaust tubing showed no problem...
 
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