PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619  LESSON 2/TASK 3 
FIGURE 75.
CLOSED COOLING SYSTEM.
4.
Air Cooling Systems
a.  An air-cooled engine uses air as the principal cooling medium (figure 76 on the
following page).  Air-cooled engines are very easily identified by separate finned
cylinders,  finned  cylinder  heads  and,  in  most  cases,  large  cooling  fans  and
extensive duct work.
b.  The primary means of removing heat from an air-cooled engine is by dissipation 
to the air.  The duct work and the cooling fans cause a constant flow of air over
and around the cylinders and cylinder heads.  The finned design of these components
add a tremendous amount of surface area to then so they are able to dissipate an
adequate amount of heat.
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