Air cooled or liquid cooled?

popaviator

popaviator

Well-Known Member
My student asked me what was a better type of engine. Air cooled or Liquid cooled. I went on to explain that heat is transfered to the air more slowly in an air cooled engine than a liquid cooled engine, and then showed him the fins on a cylinder....then he asked well...."which one is better"? So what do you guys think? and how many different types of "liquids" can cool an engine?

thanks!
 
Air cooled = less components to break, no fluid to mess with, and reduced weight.
 
The liquid cooled Thielert Diesel has serious cooling issues during the summer in the Southwest US.
 
Had a major coolent leak in a liquid cooled aircraft that left me grounded one day. Never had any cooling problems with air cooled engines.


P.S I do like how with liquid cooled enignes there is not much of a need to turn into the wind on a run up.
 
Left Seat said:
P.S I do like how with liquid cooled enignes there is not much of a need to turn into the wind on a run up.
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I noticed that up here nobody does that, they turn so as not to create a hazard for other aircraft.
 
The extra 400 seemed pretty ahead of its time with not only airframe but engine design. It featured a continental TSIOL-550-C Voyager liquid cooled engine that was monitored electronically. Single throttle/thrust lever like a DA-42. The main benefit is one doesn't have to worry about shock cooling the engine. With that aircraft you could go from cruise power @ 25,000ft to idle with no issues at all. Could easily make quick descent profiles. Also with liquid cooling the aircraft has less issues of thermal cycles/ wear in tear, everything warms and cools uniformly.

There is the issue with weight and making things more complicated with another fluid system. I personally think aircraft may switch to liquid cooling down the road along with almost all Diesel power.
 
PGT said:
I noticed that up here nobody does that, they turn so as not to create a hazard for other aircraft.
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:yeahthat:

Casting aside extreme surface temps, it is highly unlikely your typical air-cooled Lycoming is going to overheat in the 15 seconds or so you have to run up to 2,000RPM.
 
It will be virtually impossible to make a high performance, reliable air cooled diesel. Liquid cooling would also allow for higher performance gasoline engines in aircraft if we ever went that direction.

While it adds complexity, it also affords significant advantages in terms of thermal cooling capacity and significantly more stable temperatures.

jdlilfan said:
The extra 400 seemed pretty ahead of its time with not only airframe but engine design. It featured a continental TSIOL-550-C Voyager liquid cooled engine that was monitored electronically. Single throttle/thrust lever like a DA-42. The main benefit is one doesn't have to worry about shock cooling the engine. With that aircraft you could go from cruise power @ 25,000ft to idle with no issues at all. Could easily make quick descent profiles. Also with liquid cooling the aircraft has less issues of thermal cycles/ wear in tear, everything warms and cools uniformly.

There is the issue with weight and making things more complicated with another fluid system. I personally think aircraft may switch to liquid cooling down the road along with almost all Diesel power.
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ALL aircraft engines are liquid cooled.


































Did ya forget about the oil???

I had a professor in a Part 147 school that used this true/false question on his exams. I guess he was technically right, but man was it aggravating!!
 
Seems to me that the enemy of airplanes is weight. Liquid cooled engines are heavier - coolant, etc. There also exists one more system to break if you are fying a water cooled motor. There is a reason that the Navy and Marines operated liquid cooled radials when they were operating piston airplanes - light weight as well as durability. My opinion is that if liquid cooled were superior, or even as good, they would have been the standard. They certainly weren't unknown to aviation in the early days because liquid cooled motors were numerous with the largest proponent being Curtiss. I simply think that when Wright started to mass produce the radials (see the previous "Do you know your history?" question - I forget the number) that the world realized it was a better idea.
 
The Katanas I flew had liquid cooled Rotax engines. Compared to their Lycoming counterparts found in 152s/172s I found them to be much more prone to overheating. Hot/humid day while climbing out especially.
 
ppragman said:
Nothing happens, in fact its better, less stress on the coolant pump.
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On the history channel they showed the old airplanes that were liquid cool, tend to freeze up during the winter time and they had to try and keep them from freezing. That is when they introduced air cooled.
 
SFCC/UND said:
On the history channel they showed the old airplanes that were liquid cool, tend to freeze up during the winter time and they had to try and keep them from freezing. That is when they introduced air cooled.
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If you're using something that doesn't freeze as a coolant then it works great. The problem is too many moving parts/ too heavy.
 
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