Definition
A metal casing that wraps around the exhaust muffler on a piston aircraft engine, creating an enclosed space where outside air is heated by contact with the hot muffler before being routed to the cabin heater and the carburetor heat system.
Plain English
A metal jacket built around the exhaust muffler. Outside air flows through the gap between the muffler and the jacket, picks up heat from the hot muffler, and is then piped into the cabin to warm the pilot or into the carburetor to prevent ice.
Context Anchor
Seen in discussions of aircraft exhaust systems, cabin heat, and preflight inspection of heating parts near the engine.
Derivation
Shroud comes from the Old English scrud, meaning a garment or covering. The shroud is literally a cover wrapped around the muffler, holding heated air in place long enough to be useful.
Why Pilots Care
It supplies cabin heat and carburetor heat while keeping exhaust fumes safely separated from the air the pilot breathes or the engine ingests.
Grounding Statement
Fresh air passes around the hot muffler inside the shroud, picks up heat, and can then be directed into the cabin.
Intuition Check
A muffler shroud is not a scarf-like wrap or just a sound cover. In this context, it is a metal cover that helps capture heat from the muffler.
Example Sentence 1
During the annual inspection, the mechanic removed the muffler shroud to check the muffler for cracks before the winter flying season.
Example Sentence 2
The pilot selected carburetor heat and felt warm air drawn from around the muffler shroud enter the intake.