As you walk around the airplane, inspecting it
in preparation for flight, try to remember what all the components are. Ask
your flight instructor, or someone from your school's maintenance unit to
identify anything you aren't sure of. This isn't a complete walkaround, just
a few pictures.
Under normal operating conditions,
air enters through the square black engine air intake under
the landing light and goes to the carburetor.
When the carb heat knob is pulled out, air comes instead through the carb
heat intake. Air from the carb heat intake passes through a shroud around
the exhaust manifold, heating the air before it reaches the carburetor.
The picture shows a Cessna 150. In a C152 or a C172 the carb heat intake
is the open area of the cowling around the nose gear, underneath the normal
engine air intake.
When the cabin heat is selected on, air coming through the cabin heat intake
is similarily heated around the exhaust manifold.
The spinner has nothing to do with air intakes, it's just in the picture.
The second picture shows a different
Cessna with the cowling off. If you follow the orange hoses from the air
intakes to the exhaust shrouds, you can see how the air is heated.
The exhaust never touches the intake air, but the intake air passes around
part of the exhaust manifold, like you wrapping your hands around a hot cup
If you have a chance to see the airplane you fly while it is in the maintenance
hangar, take advantage of it. You'll see a similar arrangement. Follow
the hoses carefully to figure out which intake is for carburetor heat and
which is for cabin heat.
This page written 10 November 2003 by Robyn Stewart.
Copyright 2003 Flying Start
Robyn's Flying Start Home
Overview of flight training
Carb heat, engine air and where it goes
Cabin air, overhead vents and OAT
Aileron trim, rudder trim and elevator trim
Comm, VOR, ADF & ELT
Tricycle & conventional
Search all of wabyn.net
Send me e-mail