Exhaust Why only steel for expansion pipes?

[KCvale]

i know it runs a bit cooler, but um...

That pipe must be for an RC plane as it don't have enough pipe for engines.

 

[HeadSmess]

well, rc cars, yes...they tend to run closer to 26000 rpm rather than 6000...so are substantially shorter.

just an example that yes, pipes can be made from aluminium if one desires.

 

[Deleted member 12676]

the silencer you see on my bike at http://www.dragonfly75.com/motorbike/ is made of aluminum
as are many silencers for motocross bikes