Definition 1 of 2
Definition
The system of metal tubing that collects burned gases from the engine cylinders after combustion and channels them into a single outlet, typically routing them through a muffler and out the exhaust pipe. In most piston aircraft engines, the exhaust manifold also supplies heat to the cabin heater and the carburetor heat system by passing fresh air through a shroud around the hot manifold piping.
Plain English
The set of pipes that gather the hot gases leaving each cylinder after the fuel burns, and carry them out of the engine. The same hot piping is also used to warm the cabin and to provide hot air to the carburetor when needed.
Context Anchor
Seen in engine system descriptions, preflight inspection discussions, and maintenance write-ups about exhaust leaks.
Derivation
From Latin manifestus, meaning 'made obvious' or 'open to view,' which evolved into the engineering sense of a pipe or chamber with multiple openings that branch into one. The exhaust manifold is the 'many-into-one' pipe collecting exhaust from several cylinders.
Why Pilots Care
Cracks or blockages here create back-pressure that reduces engine power and can allow carbon monoxide into the cabin.
Intuition Check
Do not think of the exhaust manifold as just the tailpipe. The manifold is the collecting part near the engine; the tailpipe is where the gases finally leave the airplane.
Example Sentence 1
During preflight, the mechanic inspected the exhaust manifold for cracks, since any leak could send carbon monoxide into the cabin heater.
Example Sentence 2
A loose exhaust manifold clamp can cause a noticeable loss of engine performance.