After an issue with my exhaust system, wanted to know if anyone else has suffered problems with a Titanium exhaust system? One minute we were flying along happily, next second the engine became extremely loud….. understandable when you see it didn’t just crack, it failed totally.
What plane/engine model was this installed on?
Rotax 912iS was the engine…. installed on my GoGetAir G750
Generally speaking, titanium is not a high-temperature metal, even the best titanium alloys are normally rated to a maximum of 600°C or so.
Burnt my leg getting off my Ninja with a massive titanium pipe, but that’s not so helpful I guess. 🤪
Good thing it’s being replaced under warranty……
Ultranomad wrote:
Generally speaking, titanium is not a high-temperature metal, even the best titanium alloys are normally rated to a maximum of 600°C or so.
@Ultranomad, what is the alternative? Stainless steel? Inconel (or other superalloy)?
Inconel is the best, stainless is next. There are however multiple grades of each, making selective truths possible.
Titanium is a weird choice for an exhaust – maybe done by Marketing?
arj1 wrote:
what is the alternative? Stainless steel? Inconel (or other superalloy)?
Inconel is certainly the best possible alternative, but very expensive to weld. However, it is now possible to 3D print Inconel 718 and 625 cheaper than fabricating the same parts by welding. I haven’t yet heard of production use of Inconel printing in aerospace, but there is certainly a lot of interest, so we’ll probably see it pretty soon.
Heat-resistant steels are usually high-chromium high-nickel austenitic grades. Some of them are even rated above 1000°C, but they are often susceptible to embrittlement under continuous operation at 600-800°C, which is exactly our range of interest.
Titanium is commonly used for motorcycle and car exhausts when weight is a major issue, mostly for racing applications. For this reason the tubing wall thickness is typically very thin, which contributes to cracking. It doesn’t often fail in street applications but in severe high power service it’s typically replaced yearly.
