5000hp; 6000lbs -Lycoming

N801BH said:
I respectfully disagree...

The biggest enemy is heat and an aircooled motor that runs cylinder head temps of 400 f and then back to ambient repeatedly will suffer metal fatigue faster then a watercooled motor will suffer a coolant leak.. I have three cars /trucks and water cooled plane in my possesion now... Not once in the combined 1 million miles on the vehicles and 400+ hours on the plane have I had a liquid coolant issue. I am betting the vehicle you drive is pretty much bulletproof too..:yesnod::yesnod::yesnod:.

That reason to not use liquid cooled motors in a plane is just an Old Wives Tale..........
IMHO.
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Ben, I think the enginners that designed the air cooled radial engines for WWII bombers and the DC-6 were well aware of water cooled engines. After all early automobiles used water cooled engines. But as far as cooling a car environment is different from an airplane. An airplane is most of the time doing 150mph in cold air while a car during rush hour maybe doing 30mph in a 90degF air. And unlike airplanes cars rarely run at over 50% power on the highway so cooling is not that critical at high speed. Air cooled engines are reliable or more than water cooled engine. Have you ever seen a water cooled lawn mower or portable generator. Even motorcycles like the Harley-Davidson are air cooled. Water cooled engines is more applicable for big engines where there is a restricted flow of air or there is plenty of water (boats).

José
 
Piloto said:
Ben, I think the enginners that designed the air cooled radial engines for WWII bombers and the DC-6 were well aware of water cooled engines. After all early automobiles used water cooled engines. But as far as cooling a car environment is different from an airplane. An airplane is most of the time doing 150mph in cold air while a car during rush hour maybe doing 30mph in a 90degF air. And unlike airplanes cars rarely run at over 50% power on the highway so cooling is not that critical at high speed. Air cooled engines are reliable or more than water cooled engine. Have you ever seen a water cooled lawn mower or portable generator. Even motorcycles like the Harley-Davidson are air cooled. Water cooled engines is more applicable for big engines where there is a restricted flow of air or there is plenty of water (boats).

José
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I've seen water-cooled motor cycles. Some BMWs off the top of my head.

You are also forgetting that small engines have more surface area for their size than larger engines. Volume grows as a function of the radius cubed, but surface area only increases as a function of radius squared. Put simply, the heat has less area to escape from as the engines get larger. That means a more-efficient cooling system is needed. The engine in question is a very big engine.
 
Cap'n Jack said:
I've seen water-cooled motor cycles. Some BMWs off the top of my head.

You are also forgetting that small engines have more surface area for their size than larger engines. Volume grows as a function of the radius cubed, but surface area only increases as a function of radius squared. Put simply, the heat has less area to escape from as the engines get larger. That means a more-efficient cooling system is needed. The engine in question is a very big engine.
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Any of the bikes where performance is desired - are liquid cooled (so essentially every sportbike and performance touring bike). More horsepower in less space.

My Concours is a liquid cooled motorcycle. A non-issue.
 
jesse said:
Any of the bikes where performance is desired - are liquid cooled (so essentially every sportbike and performance touring bike). More horsepower in less space.

My Concours is a liquid cooled motorcycle. A non-issue.
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True- I don't know much about motorcycles except they stop faster than I and they are harder to see than a SUV, so I don't follow them closely while trying to be aware of them.
 
Cap'n Jack said:
I've seen water-cooled motor cycles. Some BMWs off the top of my head.

You are also forgetting that small engines have more surface area for their size than larger engines. Volume grows as a function of the radius cubed, but surface area only increases as a function of radius squared. Put simply, the heat has less area to escape from as the engines get larger. That means a more-efficient cooling system is needed. The engine in question is a very big engine.
Click to expand...

There are very few air cooled motorcycle engines left, mostly little 3rd world cheapie 2 stroke stuff.
 
Henning said:
There are very few air cooled motorcycle engines left, mostly little 3rd world cheapie 2 stroke stuff.
Click to expand...

Harley Davidson still uses air cooled, as well as several models of Honda and Suzuki. All 4 strokes and sold here in the US.
 
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Henning said:
There are very few air cooled motorcycle engines left, mostly little 3rd world cheapie 2 stroke stuff.
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This looks air cooled:
12-superlow-bs.jpg


As does this too:
12-1200-custom-bs.jpg


and a 2012 models too. Harley still builds a lot of bikes.

This isn't a Harley, but looks air-cooled:
overview_darkhorse.jpg
 
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A good portion of the V-twins like that are still air cooled mostly because they're trying to copy Harley whom has no need to innovate - they've got their market figured out.
 
??? Like I said, a few, the cruisers for visual appeal and nothing else, and the small bikes because those are the models that they make in Indonesia for the third world market.
 
Cap'n Jack said:
I've seen water-cooled motor cycles. Some BMWs off the top of my head.

You are also forgetting that small engines have more surface area for their size than larger engines. Volume grows as a function of the radius cubed, but surface area only increases as a function of radius squared. Put simply, the heat has less area to escape from as the engines get larger. That means a more-efficient cooling system is needed. The engine in question is a very big engine.
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And one of the best features of that engine is, it could be cooled by a leading edge de-/anti-icer, which means the leading edge of the wing would never ice up. It didn't need a radiator sticking out in the wind.
 
Tom-D said:
And one of the best features of that engine is, it could be cooled by a leading edge de-/anti-icer, which means the leading edge of the wing would never ice up. It didn't need a radiator sticking out in the wind.
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With water cooling you can save a lot of drag by using much more aerodynamic methods of heat exchange, leading edge heat exchange extrusions are one great way, and then you might as well put hot water 'rocket' in the belly like the P-51 which you can also manage to pull energy for your climate control from. Water cooling also allows for a more efficient pusher. With contra rotating prop you can build such a cool SE plane as well.
 
And what happens at vx on a hot day to the io-360? How long can you keep it up?
 
Henning said:
With water cooling you can save a lot of drag by using much more aerodynamic methods of heat exchange, leading edge heat exchange extrusions are one great way, and then you might as well put hot water 'rocket' in the belly like the P-51 which you can also manage to pull energy for your climate control from. Water cooling also allows for a more efficient pusher. With contra rotating prop you can build such a cool SE plane as well.
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The best advantage for air-cooled ? they can take a hit and keep running. A loss of 1 cylinder simply gives ya a rough runner. 1 hit in the water jacket, she is going to quit pretty soon.
 
Tom-D said:
The best advantage for air-cooled ? they can take a hit and keep running. A loss of 1 cylinder simply gives ya a rough runner. 1 hit in the water jacket, she is going to quit pretty soon.
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Haven't been shot at recently.
 
Continental and Lycoming keep doing what they do because like Harley in a way, they have a captive market, and there's no incentive for them to spend on R&D, and given the volume of the market, there were very few threats from potential new entrants.

Now that Rotax puts on the market liquid-cooled engines with 2000h TBO's and same power-to-weight ratios as the famous IO-360 above with the added benefit of simpler operation and lower costs people are eventually going to notice... and while Thielert / Austro aren't there just yet in terms of reliability, they'll eventually get there too - in spite of the "you can't run an auto engine continuously at 75% power output" brigade.
 
Tom-D said:
The best advantage for air-cooled ? they can take a hit and keep running. A loss of 1 cylinder simply gives ya a rough runner. 1 hit in the water jacket, she is going to quit pretty soon.
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Very true. Not to mention that on a water cooled engine you do not replace individual cylinders but the whole engine block.

José
 
Skylane81E said:
And what happens at vx on a hot day to the io-360? How long can you keep it up?
Click to expand...

On my Mooney 201 with cowl flaps open CHT barely gets to 300F during a Vx climb.

José
 
Dan Thomas said:
As an aircraft mechanic I can tell you that cylinders seldom go "bad." A water-cooled engine will have even less trouble that way. That big Lycoming wouldn't give any more trouble than the Lycomings in countless light aircraft and probably less.

Hand-propping that engine would be impossible, but it's also impossible to hand-prop big radials or jet engines of any sort.

Dan
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Actually there is a system for "hand propping" a big radial. It has several bungee cords with a cuff that fits over the top of a blade. You get 3 or 4 guys holding the bottom blade with the first guy holding onto the blade and the others holding on to each others waist. The bungee goes on the top left blade and 3 or 4 other guys stretch the bungee. When all is ready the front guy lets go of the blade and they all get the heck out of the way as the bungee pulls the prop through. I have seen pictures of this in action but I can't find any. There is also the "Huck Starter" popular in the 30's and used a lot by Russia in WWII. Don
 
Piloto said:
Very true. Not to mention that on a water cooled engine you do not replace individual cylinders but the whole engine block.

José
Click to expand...

Rotax cylinders can be removed individually.
 
Piloto said:
On my Mooney 201 with cowl flaps open CHT barely gets to 300F during a Vx climb.

José
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Why do you keep comparing a small engine to a large one?

As I mentioned before, the area to dissipate heat on a large engine is smaller compared to the small one.
 
Cap'n Jack said:
Why do you keep comparing a small engine to a large one?

As I mentioned before, the area to dissipate heat on a large engine is smaller compared to the small one.
Click to expand...

You are right Jack is not worth it water cooling small engines.

José
 
Dan Thomas said:
I believe that huge ship engine is a two-stroke that is directly connected to the propeller. They run the engine backwards for reverse. The starter would likely be another, much smaller diesel engine. Old earthmoving equipment was started that way: with a "pup" engine.

Dan
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Pony motor. I used to be a super for an old paving company that had a Cat dozer that you started with a pony motor. It was a union shop so I could not run equipment (and this antique just sat in the yard anyway) but I started it once for fun. Below vid shows the process.

http://www.youtube.com/watch?v=MHr5E3HQ8BA

At my present job, I am involved with regulatory compliance for a number of 4000 hp EMD diesels (mostly 20 cyl 645's) - they start with compressed air.

They start like this:
http://www.youtube.com/watch?v=6fpZF5oqnF0
 
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Tom-D said:
The best advantage for air-cooled ? they can take a hit and keep running. A loss of 1 cylinder simply gives ya a rough runner. 1 hit in the water jacket, she is going to quit pretty soon.
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I have some time in the CTLS w/Rotax. It is combo water/air-cooled. If you loose the water, you can fly 45 minutes before they consider that you will damage the engine. Throttle down to keep it cool and find an airport - no big problem.
 
Piloto said:
Very true. Not to mention that on a water cooled engine you do not replace individual cylinders but the whole engine block.

José
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No sir, cylinder sleeves are exchangeable. Most small inexpensive engines require a machining process to do so, but sleeves are available for everything. Larger and more expensive engines will have removable cylinder sleeves.

That means you just change out the $25-$75 sleeve instead of the entire >$1000 cylinder and head assembly.
 
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Skip Miller said:
The Sulzer ship engine pictured above in this string cruises at 100 - 102 rpm.

-Skip
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It's pretty much all it ever turns. It'll likely be connected to a variable pitch prop and they'll just add fuel as they add prop pitch. It also saves you from stopping and starting the engine for neutral and reverse.
 
If the chief engineer likes air cooled engines, you build air cooled engines. If the chief engineer likes liquid cooled engines...

And sometimes marketing (or, worse, an executive V.P. or CEO) sticks their finger in the pie, just to make things difficult for us engineers.
 
Henning said:
With water cooling you can save a lot of drag by using much more aerodynamic methods of heat exchange, leading edge heat exchange extrusions are one great way, and then you might as well put hot water 'rocket' in the belly like the P-51 which you can also manage to pull energy for your climate control from. Water cooling also allows for a more efficient pusher. With contra rotating prop you can build such a cool SE plane as well.
Click to expand...

I'd wondered the same in a couple of variations....
1) D shaped spar/leading edge made of SS and doubles as the exhaust pipe
2) Tiny tubes bonded to to the skin of the AC to allow the passing air to act as your heat sink
etc.

I posted the "skin" question over at homebuiltairplanes and they commented on how the heat rising/emanating from the skin causes a not insignificant performance hit. I don't really follow all the ins and outs, but I do recall that being mentioned.
 
jhausch said:
.......I posted the "skin" question over at homebuiltairplanes and they commented on how the heat rising/emanating from the skin causes a not insignificant performance hit. I don't really follow all the ins and outs, but I do recall that being mentioned.
Click to expand...
.

Ya got to be careful who you believe over at homebuiltairplanes.. The site appears to be filled with armchair /keyboard engineers who have never built anything, and in some cases don't even know how to fly... Their expertise is the ability to scan the internet, cut and paste stuff that fits their agenda and claim they know it all....
As for the elevated skin temp deal...Kinda makes ya wonder how the Concorde flew as good as it did... I seem to remember reading that the leading edge temps were in the 200 f range..:dunno::dunno:
 
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jhausch said:
I'd wondered the same in a couple of variations....
1) D shaped spar/leading edge made of SS and doubles as the exhaust pipe
2) Tiny tubes bonded to to the skin of the AC to allow the passing air to act as your heat sink
etc.

I posted the "skin" question over at homebuiltairplanes and they commented on how the heat rising/emanating from the skin causes a not insignificant performance hit. I don't really follow all the ins and outs, but I do recall that being mentioned.
Click to expand...


Don't recall performance being a skin heat related issue with the X-15, SR-71 or Concorde. I've read in depth on all three of those programs and can't recall that once being mentioned even.:dunno:
 
jhausch said:
I'd wondered the same in a couple of variations....
1) D shaped spar/leading edge made of SS and doubles as the exhaust pipe
2) Tiny tubes bonded to to the skin of the AC to allow the passing air to act as your heat sink
etc.

I posted the "skin" question over at homebuiltairplanes and they commented on how the heat rising/emanating from the skin causes a not insignificant performance hit. I don't really follow all the ins and outs, but I do recall that being mentioned.
Click to expand...

Isn't a problem, but must be considered when determining the behavior of the airfoil. You are adding energy to the airflow over the wings (via heat transfer) and that will change how the air flows as compared to a cold wing. Adding that energy can actually cause the flow to separate earlier.

Henning brought up the SR-71. On the SR-71 they used cold fuel to cool the skin of the aircraft, so they were removeing energy from the flow which should cause it to stay attached longer. Thoug, the SR-71 was moving in the high mach numbers, so aerodynamics sorta becomes voodoo.
 
COFlyBoy said:
Henning brought up the SR-71. On the SR-71 they used cold fuel to cool the skin of the aircraft, so they were removeing energy from the flow which should cause it to stay attached longer. Thoug, the SR-71 was moving in the high mach numbers, so aerodynamics sorta becomes voodoo.
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I recall reading the skin cooling with fuel was due to structural considerations rather than aerodynamic.
 
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