Air Cooled Water jacket engine ?

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Dan Thomas

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I think you are focusing on the minor and missing the major .
What are the advantages of a liquid cooled engine?
What are the disadvantages?
Same with the air cooled ?
Could we get most of The advantages of both ?
Perhaps we need to use a different liquid ?
This subject has been discussed here many times. Use the site's search engine and inform yourself before challenging the answers you get.
 

Dan Thomas

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The BMW S58 produces 280hp at 2700 rpm so you could do that direct drive with a simple and light bearing housing to take the prop loads.
Those are good numbers. I'd like to see that work out.
 

WonderousMountain

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Evans WaterLess coolant is as good as it gets.
No rust, corroding, boil over, or high pressure lines.
Unfortunately, it does not cool more effectively than
Water, or produce less resistance under flow.

We're not saying no, we're saying thicis an unusual setup.

Avoiding a radiator, hoses, etc.
Is an advantage, there are some good points to it.
 
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pictsidhe

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Evans WaterLess coolant is as good as it gets.
No rust, corroding, boil over, or high pressure lines.
Unfortunately, it does not cool more effectively than
Water, or produce less resistance under flow.

We're not saying no, we're saying thicis an unusual setup.
Evan's has poor heat conduction. You may not boil, but you are more likely to overheat.
 

wsimpso1

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I think you are focusing on the minor and missing the major .
What are the advantages of a liquid cooled engine?
What are the disadvantages?
Same with the air cooled ?
Could we get most of The advantages of both ?
Perhaps we need to use a different liquid ?
I think we described the issues of your original post. I prefer to buy my engines already developed - they are terribly complicated things to get right in all the details, let alone attempting to invent new stuff and then develop the engine to commercial and technical viability.

Air cooled engines are somewhat simpler and lighter than liquid cooled engines.

Liquid cooled engines can manage heat at higher power levels but are more complicated, usually heavier, require either a well planned set of ductwork for low drag or a lot of radiator and drag to make the cooling work.

Both can work, make suitable power per unit weight and per unit fuel burn over a wide range of peak power.

Combine to get the advantages of both? Not likely. We have been building and developing spark ignition piston engines for about 140 years, with huge numbers of smart people involved in the processes and the world has converged on the two conventional schemes a long time ago. You are proposing this like it is a new idea. I suspect it is not, but has been examined and found wanting. I already detailed how on first principals an engine with a water jacket and then fins would end up much larger than one without the water jacket. Your invention raises the thermal resistance of the system which then either raises temperatures everywhere (bad for longevity) or must have much more fin area to achieve the same combustion chamber wall temperatures, which increases both engine weight and air flow required to make it work.

If you want to get into details, I am certain that there are textbooks and technical papers on each.

Now, as to a different fluid.

Water is terrific for heat capacity and heat transfer, cheap, but boils at too low a temperature and freezes at too high a temperature;

There are a variety of glycols, which are technically alcohols, with higher boiling points but lower heat capacity and lower heat transfer capabilities, plus they will be a terrific fuel in a fire/ Rolls Royce played with it in the 1930's, went back to water/ethylene glycol;

Mixes of water and ethylene glycol have the nice features of higher boiling points than either alone, suitably lower freezing points, and still give decent heat capacity and heat transfer. These also have the good features of supporting inexpensive corrosion inhibitors, seal and bearing lubricants - corrosion inhibitors are sacrificial, and so antifreeze as it is called is periodically replaced;

Oils of huge variety of density and viscosity exist, but they are woefully short on thermal capacity and heat transfer, and also raise risks of fire;

Other materials might be available. In the nuclear power reactor business, water based coolants still dominate, while liquid metal cooling was used in breeder reactors. Trouble with liquid metals is that they run at higher temperatures than most find practical, they can never be cooled down without either evacuating the cooling system or wrecking the system, and when they leak, they tend to burn with noxious combustion products.

Going further with these trains of thought are a good excuse for obtaining an engineering education or at least doing a bunch of independant research.

Billski out.
 

wsimpso1

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But that begs the question, are they cooler further out because of distance or because they are dissipating heat better out there where the air is cooler (hasn’t been heated by a longer trip through the fins)? Of course, another takeaway from that line of thought is that shorter fins Are lighter and they work better because the cool air gets in closer to the source of the heat where the delta-T can be maintained at a higher level.
Come on Bruce, heat flows from hot to cold, into the fin at its root, up the fin and out into the air as the remaining heat moves further up the fin. Air at the surface of the fin takes away heat at a rate related both to the air speed past over the surface and proportional to the difference in temperatures. Imagine a small element of the fin - Heat in at the base end equals heat out in the air plus heat remaining going out to the next element. Less heat in to the next element means that next element is cooler... Even with tapered fins, the temp drops as you go out the fin. And as temp difference drops, the heat transferred at each increment away from the base drops. This stuff has been modeled and tested, with the theories well validated before we were both born.

Bill
 

Dan Thomas

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Really ?
I did ,you might want to take your own advice.
I've been here a long time and have read extensively. I also designed and carried out the entire installation of a Subaru in a Glastar, including the liquid cooling system, and flew it sucessfully. What's your experience?
 

Pilot-34

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I think we described the issues of your original post. I prefer to buy my engines already developed - they are terribly complicated things to get right in all the details, let alone attempting to invent new stuff and then develop the engine to commercial and technical viability.

Combine to get the advantages of both? Not likely. We have been building and developing spark ignition piston engines for about 140 years, with huge numbers of smart people involved in the processes and the world has converged on the two conventional schemes a long time ago. You are proposing this like it is a new idea.

Billski out.

Sorry Bill your advice is spot on and I was wrong.

My mother told me if I couldn’t say anything nice to keep my mouth shut
It’s sage advice that I should take more often.
 
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Pilot-34

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I've been here a long time and have read extensively. I also designed and carried out the entire installation of a Subaru in a Glastar, including the liquid cooling system, and flew it sucessfully. What's your experience?
I have painted the balloons on a lawnchair.

But more relevant I have used the search function on the site a lot.
Including immediately before I posted the thread.
 

Pilot-34

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Yes really.
Yes In fact if you can prove me wrong I would be perfectly willing to shut up and quit bothering you by having ideas forever.
Would you be willing to engage in that wager by promising to quit being a negative Nelly if you can’t prove me wrong?
 

wsimpso1

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Bill I’m sure you’re trying to help.
...
But I think that attitude totally entitles you to stay out of this discussion.
...
Now please quit peeing on the parade we’re having fun here.
Ok, let's summarize. You asked a series of questions, I cited them, answered the questions, told you what the technical issues were with the cooling system design you were proposing using first principals, and with alternate coolants, and pointed out that you were unlikely to invent something new in piston engine design.

In response, you asail my character and tell me not to "pee on the parade". I suspect that you will now find difficulty getting realistic responses on this forum. I know I sure won't help you again.

Billski
 

Dan Thomas

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The SMA 305-230 is a French, certified diesel aircraft engine. It has oil-cooled heads that have fins on them. There is a massive oil cooler as part of the installation.
1601742320309.png
See, there isn't much in aviation history that hasn't been discussed or tried. One just needs to know his history.

Ten years ago I did some work on an SMA in a 182. At that time SMA had spent a billion dollars on its development and had 50 engines flying worldwide. That just shows how difficult and expensive it can be to create something radically different these days. And it's why we're still using the engines we're using.
 
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Pilot-34

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Ok, let's summarize. You asked a series of questions, I cited them, answered the questions, told you what the technical issues were with the cooling system design you were proposing using first principals, and with alternate coolants, and pointed out that you were unlikely to invent something new in piston engine design.

In response, you asail my character and tell me not to "pee on the parade". I suspect that you will now find difficulty getting realistic responses on this forum. I know I sure won't help you again.

Billski
I did not mean to assail your character, I honestly believe that you are one of the smartest and most honest people here.
I’m just begging you to let our flights of fantasy continue for a little.
What I would really like is if not just you but everyone will address negatives by saying “in the past it didn’t work because of X “but now if we do Y we might be able to get halfway to the target.

See that’s the thing about rehashing old problems from years ago all they had was cast-iron then someone invented steel, Since then titanium chromium and carbon fiber has come along so we can do things that we couldn’t do at the beginning of time.
 

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