air-cooled 
adjective
(Especially of an engine) cooled by means of a current of air.The Americans were developing larger tanks, with cast-armour hulls and turrets, better guns, and air-cooled diesel engines....
- Sitting almost upright on one of its floats, only the severe damage to the front end, where its 14-cylinder, air-cooled radial engine was partially torn away on impact, betrays the violence that saw this aircraft downed.
- The Navy reasoned that air-cooled radial engines offered added reliability, especially when operating over water.
- breaking and entering
- breaking ball
- breaking capacity
- breaking cart
- breaking news
- breaking point
- break into
- break in two
- breakneck
- break new (or fresh) ground
- break of day
- break off
- break of serve
- break one's back
- break one's duck
- break one's neck to do something
- break (one's) stride
- break (or informal kick) the habit
- break (or keep) faith
- break out
- breakout
- break out in
- break point
- breakpoint
- break rank