Header Wrap

[GrassStripFlyBoy]

Update on the header wrap, several flights now into the hot summer weather, I was not struggling with high temps but would see them entering into the yellow on the long climb outs.  Besides the lower oil & CHT temps, it's nice to pull the cowl and find the springs staying nice and clean too.  I'm sure some of the exhaust leakage was corrected by cleaning and servicing the joints, but the extra benefit on wrap is bonus too.

[Roger Lee]

Nice job

 

[GrassStripFlyBoy]

4 hours ago, Roger Lee said:

Nice job

 

Thanks Roger, certainly not a fun task installing, but rewarding in the end.

[Bill3558]

Is this a legal modification for SLSA planes?  I’d like to do that. I’m pushing 245 on warm Climb outs. Where did you get the wrap?

thanks for info

[Anticept]

There's a blanket MRA in on this forum for it.

[Roger Lee]

It takes me a little less than an hour to do it. Just make sure you DO NOT over wrap each wind more than about 3/8". An over wrap of about half will retain too much heat and can cause a problem with the exhaust pipe.

[Tom Baker]

You might also want to check out this on the subject of header wrap. 

sl-912-025.pdf

[Roger Lee]

Myself, Rotech and a couple of people had this conversation on Rotax-Owner.com owned and run by Rotech.

They said the same thing about the SI. I reminded them that thousands of owners have header wrap and without issues. I told them the same about over wrapping and that's what most likely caused the pipe issues in their pictures which I have brought up here too. I bet I have wrapped at least 70-80 Rotax engines and never had a single issue. Then when Rotech said something about not doing it I reminded them that they work on Stemmie motor gliders and that is only one Mfg that wraps at the factory and that Rotech  works on them and that Rotech also wraps those pipes. They never said anything else after I reminded them they wrap headers too. It's like anything else, do it wrong and you can cause yourself issues. It never hurts to make a phone call to someone and find out the tips, tricks and in's and outs.

[Anticept]

I am willing to bet a big part of that is custom exhausts or poor cooling.

I had two or three engines wrapped, in a flight school environment, and never had pipes do that. Those engines have since been replaced due to TBO.

[GlennM]

It is common for people to wrap the headers of race cars, too.  I chose to have a ceramic coating flame sprayed on the outside of my race car exhaust pipes for the same reason.  I do not like the looks of the wrapped headers after the are run a while.  Swain coatings has a .012" thick ceramic that actually keeps the heat down. The .001-.002" ceramic coatings that they also offer only keep the pipe from corroding and don't really block any heat.  If I had issues on my plane with high temps,  I would consider getting an MRA for the ceramic coating.

[Bill3558]

“Insulating the exhaust pipes (e.g. with exhaust wraps or ceramic coatings) leads to a significant increase in the component temperatures of all exhaust-relevant components. The significant addi- tional thermal load generated inevitably reduces proven durability of exhaust components. Exhaust wrap may also hold moisture, promoting corrosion.
The use of any insulation material is not approved by ROTAX® and may result in exhaust compo- nent fatigue and damage.”

Ill stay stock.

[Anticept]

Literally everything without a rotax label on it is not approved by rotax, and this is just legal butt covering.

They didn't issue this service bulletin until they found those few edge cases, despite making aircraft engines since 1986.

[Madhatter]

26 minutes ago, Bill3558 said:

“Insulating the exhaust pipes (e.g. with exhaust wraps or ceramic coatings) leads to a significant increase in the component temperatures of all exhaust-relevant components. The significant addi- tional thermal load generated inevitably reduces proven durability of exhaust components. Exhaust wrap may also hold moisture, promoting corrosion.
The use of any insulation material is not approved by ROTAX® and may result in exhaust compo- nent fatigue and damage.”

Ill stay stock.

That was always the consensus on certified aircraft. Just remember a new FD muffler is $2000.+ if there are any available.  The entire new exhaust system is about $6000, again if any are available.

[Anticept]

On certified aircraft, as a point to raise, the exhaust system is a significant part of the cooling system of air cooled engines. They're not much of a contributor to liquid cooled though.

[Madhatter]

My CT egt's are pretty much the same as on normalized certified engines . Water cooling helps dissipate the heat away from the cylinders more efficiently allowing higher horsepower in a smaller engine. The cylinder cooling fins on air-cooled engines must be much larger to dissipate heat.

[Roger Lee]

3 hours ago, Bill3558 said:

“Insulating the exhaust pipes (e.g. with exhaust wraps or ceramic coatings) leads to a significant increase in the component temperatures of all exhaust-relevant components. The significant addi- tional thermal load generated inevitably reduces proven durability of exhaust components. Exhaust wrap may also hold moisture, promoting corrosion.
The use of any insulation material is not approved by ROTAX® and may result in exhaust compo- nent fatigue and damage.”

Ill stay stock.

But Rotax service centers like Rotech in Canada and the ones here in the US do wrap exhaust because they come that way from certain aircraft MFG's and they are not allowed to remove it so when they take it off they are required to put it back on. Thousands of Rotax have wrapped exhaust. When done correctly it does not cause an issue. When done wrong like anything you you might do it can cause an issue. Doing anything wrong on any engine can cause an issue.