Thermal exhaust wrap

[jiott]

Go to the Rotax-Owner.com website and click on forums. Do search for wrapping the exhaust and you will find quite a bit of discussion on it. My recollection is that the general opinion is that it is a good thing if done properly for many of the reasons given by Esser.

[jrevens]

Specifically regarding wrapping, I'm with Dave S. There are situations where it can be helpful under the cowl, but my considered opinion is that it is not particularly good for your expensive exhaust system. The pipes are actually going to have a greater range of thermal cycling if wrapped - the pipe itself will get hotter. With the pipes being hidden under the wrap, cracks or corrosion that are forming can be hidden, etc.

As far as ceramic coatings go, there is some controversy about the brittleness of the coating actually causing a greater possibility of cracks developing. One thing is certain - if you do have to repair the system by welding, it's a real pain to try to remove the coating... many welders will not even consider doing it. I know this from experience. Exhaust gas downstream of a turbocharger is no hotter than it is without a turbocharger... in fact it's possibly cooler.

I prefer lightweight thermal shielding if necessary, as Dave suggested.

[Av8r3400]

To pull back just a bit, what is the benefit you would be looking for to wrap the exhaust?

Personally, I don't see the need for it. The risks of damage is more than any benefit potential. I would say the same for ceramic coating as well. Other than looking pretty (very pretty for sure!) the risk reward ratio is not there.

Just my opinion.

[Esser]

I think the theory behind is it it will cool slower and more evenly. But like I said, I am no expert.

[jrthomas]

I did a post on www.rotaxowner.com aimed at Roger Lee. I'm anxious to hear what he has to say. I don't have an opinion either way so I'm open to leaving the wraps on or taking them off. I'm flying the plane now with no issues. Thanks for your comments. James Thomas

[jrthomas]

I got an answer from Roger Lee. I consider him one of the best Rotax guys out there. He says that he knows a hundred others using thermal wraps with no issues and he has run wrap for over 8 years himself. He says that the advantage is that it cuts down on under the cowl heal, which I believe is a good thing and as long as it's done correctly shouldn't be a problem. James Thomas

[KFfan]

Are you able to expand regarding "done correctly"?
Thanks

[tx_swordguy]

I do not know the effects on airplanes, however on motorcycles wrapped exhaust was/is a style kind of thing. Problems are more related to moisture being either held or retained on the exhaust pipe and then cooked off during heat cycle. (motorcycle exhaust is exposed to water on the road and during washing much more so than an airplane) Not 100% sure of the how, but what is happening is the pipes end up rusting from the outside much quicker (even when chromed). Vibration + moisture+ heat all rubbing the outside of the pipe = rusted pipes. It seems much worse on the header part where the most heat is. I think if you can shield parts you want shielded you would be better off. That being said if you don't wash or get the wraps wet, it may not even be an issue.
Mark

[jrthomas]

Answer for KFfan. Quoting from Roger: "Bottom line, it's up to you but the wrap shouldn't hurt anything if it's installed correctly. By that I mean that the edges are not over wrapped by (more than) 3/8". If it gets over wrapped by half way then that's too thick and heavy and it will retain too much heat." James Thomas