EXHAUST INSULATING WRAP

Just to add some information to this topic, the certified Stemme motorglider comes from the factory with the exhaust pipes and muffler wrapped with insulating tape, with a 50% overlap. Stemme modifies the Rotax 914 F2-01, changing the engine mounts, adding an intercooler, and other changes, so I don't know how these changes might affect the addition of insulating tape.

Mike

Rotax Owner,

No big deal I just like to chat and find and experience new things and share things I've researched. Nothing ever bothers me in post or emails. It's all good.

I'm easy. :) LOL

p.s.

I like differing opinions. It's how you learn and try new experiences.

Michael Reid wrote:

Just to add some information to this topic, the certified Stemme motorglider comes from the factory with the exhaust pipes and muffler wrapped with insulating tape, with a 50% overlap. Stemme modifies the Rotax 914 F2-01, changing the engine mounts, adding an intercooler, and other changes, so I don't know how these changes might affect the addition of insulating tape.

Mike

Yes, my normal/utility certificated motorglider also came from the factory with the exhaust pipes wrapped. It, like the Stemme, is very tightly cowled with the fiberglass quite close to the pipes. Even with a layer of insulation glued to the glass, removal of the pipe wrap puts the cowl at risk of being weakened, damaged or, in the worst case, actually catching fire. That would make for a bad day.

Bottom line: If the manufacturer sent it out the door wrapped, it needs to stay wrapped. Regardless of legalities, they didn't put it on just for the fun of it.

Note that even with the wrap, heat was degrading coolant hoses close by. Slipping on standard orange fire sleeve in those areas will significantly mitigate that issue.

Out of all the LSA aircraft I see from different MFG's about 60% have wrapped pipes. I had my Flight Design CTSW wrapped for 1500 hrs. I really believe it helps with under cowl heat and damage.

Think of it this way. If you ran your engine without wrap and shut it off would you dare touch the bare pipe? Not without losing some skin, but with a wrapped pipe I can touch it.

As a retired 30 yr. firefighter you know what radiated and convected heat can do. When I did my research I placed temp strips around the engine because I wanted to know what temps my ignition modules and VR and other electrical components were seeing. The wrap made a difference vs bare pipe. With so many owners and aircraft MFG's using it I haven't found a negative against it yet.

Here's a few pictures of some I have seen.

We have had a case with a UL airplane (Rotax 912 ULS) where the owner wrapped his manifold with heat insulation tape (with proper overlapping), which resulted in a failure of the steel pipes. They were literally burnt through. He nearly had an in flight fire emergency as a result. Engine cowling and many other parts melted by the escaping hot gasses during his flight to our base. Not so funny. We (as an airplane producer) strongly recommend to strictly follow the instruction given by Rotax (RTFM). The engine compartment should be ventilated enough as not to have too high temperatures inside. We also have a prototype with Rotax 914 in it, and even there the heat buildup (after landing on a hot day) must be kept in an acceptable range, without any heat wrap. We have temperature sensors inside the engine compartment (and also for fuel temperature to avoid vapour lock), we display the values on the glass cockpit (even with a warning). We recommend to use different methods to protect the heat vulnerable parts, utilising heat reflection and heat shields, where needed. In some aeroplanes there may not be a way around using SOME heat wrap, but pls limit it. I might even find some old notes about how much higher is the EGT in flight when measured 10 cm away from the head exhaust ports, with the wrap on. Many consider it a flashy addition to their engines, but it is not. Sometimes I am left speechless when I see those beautiful custom built café racer motorcycles of which nearly all have their manifolds wrapped all the way from the ports to the mufflers. WHY? Any proper company producing manifolds would even void their product warranty, if heat wrap is applied. Better think twice.