Water Cooled Lycoming?

[Geico266]

I found this while surfing around last night. Interesting design. Burt Rutan tried it on one of his daily flyiers, but removed it for reasons unknown.

http://www.liquidcooledairpower.com/cj-overview.shtml


Just thought I would share with you non traditional engine guys.

[gmcjetpilot]

Originally Posted by Geico266

I found this while surfing around last night. Interesting design. Burt Rutan tried it on one of his daily flyiers, but removed it for reasons unknown.

http://www.liquidcooledairpower.com/cj-overview.shtml


Just thought I would share with you non traditional engine guys.

Hey, yea check the archives here, I wrote about it. I called the liquidecooled folks and they are re-doing the design. You can imagine how expensive it is, and their market is fairly limited (experimentals). Their main problem was the sub-contractors who they got (our could not get) to do the work. Either they could not find any one to produce quality or when they found some one, they went out of business. Rutan and they did have a falling out some what. Burt expected them not only to provide the jugs for free but maintain and support all his request. Apparently water cooled jugs do what they say they will do performance wise.

Last I talked to one of the tech guys, super nice, smart and was nice enough to school me in water cooling, they are working on new cylinders. That was over a year ago. As I have criticised all water cooling, what do you do with the radiators? Cooling drag? They offer the cylinders but what about installation: cowl, radiators.....

Price last time they was in the $12,000 range I recall, set of 4, not including radiator'(s). Personally I'm an Air-cooled guy, and I don't see a big advantage. May be on a jump or tow plane that goes up full power and down fast at idle, many times a day, not shock cooling would be a big plus.

[Captain Sacto]

I've often wondered why more aircraft piston engines are not water-cooled.

I would guess that the thermal stability from liquid cooling could prevent one from barbecuing the cylinders on some muscle climbs as well as to prevent shock cooling on precipitous descents. Assuming they worked reliably, I suspect that the increase in TBO could be significant.

[gmcjetpilot]

Originally Posted by Captain Sacto

I've often wondered why more aircraft piston engines are not water-cooled.

I would guess that the thermal stability from liquid cooling could prevent one from barbecuing the cylinders on some muscle climbs as well as to prevent shock cooling on precipitous descents. Assuming they worked reliably, I suspect that the increase in TBO could be significant.

You would think, but TBO would not be much higher, if any more at all over air cooled. First 2000 hours is high. My Lyc experience is if you fly regularly, maintain it (oil changes etc) and fly/operate it, in normal ranges of temps, they go well over TBO, 2,600 hours in one I know of personally. At some point its time to take a peak inside because its a plane not a car. You may be getting confused with things like corrosion in cylinders and cams due to disuse. That kills engines fast. Water cooling would not help. Water cooled auto engines converted to plane use have not shown to have longer or even as long TBO, only cheaper overhaul prices. Also, cars may seem to have longer life, but really they operate at a very low power settings even at 65mph down the freeway, only occasionally providing any thing near 75% power or higher during hard acceleration. Normal car driving is pretty low % power, where a plane is at 75% power or higher routinely. Again check the archives. There has been much debate about water cooling. There are hard core fans of the water cooling concept and than people like me, don't see an improvement on a small airplane. All the guys who like alternative engines of course have to either be fans of water cooling or deal with it. We (airplane builders) have a huge amount of air to use, and direct air cooling is very efficient. Frankly water cooled is a misnomer, its air cooled as well, with just one extra step, the water to air heat exchanger (radiator). Also Lycs are not only air cooled but liquid cooled with oil. That's why they have a big oil coolers. Air cooled Porsche's for example have two huge oil coolers and +15 qts of oil. BMW air-cooled "Boxer" motorcycle's are also air/oil cooled. The other obstacle is airframes are designed around air cooled engines. Converting to radiators is not easy with out creating lots of drag. The P-51 was made with the engine in mind. The water cooled guys say you can get the drag down to as low or less as air cooled? May be and I wish them luck. The winner of Reno air races was flying a BIG OLD AIR COOLED RADIAL. Some times 1955 technology (the approx birth date of the modern Horz Opposed air cooled Lycs) is just right, simple, reliable and light. The last trade-off for water cooling. Water cooling, fluids, radiator, water pump weigh more, always. Air cooled is simpler and lighter, fact. The water pump takes HP as well. With the added drag from radiators and extra weight, speed and payload suffer. The advantage or water cooling, tighter internal tolerances and better emissions. Emissions at least at this time is not an issue for planes. In theory you can evacuate more heat with a water jacket around the heads and jugs. However the air cooled Lyc is designed "thermally" to work just dandy, but the trade-off is the responsibility of watching CHT and oil temp falls on the pilot. On the other hand many experimental water-cooled planes have temp issues, as smaller and smaller radiators are used to minimize drag.

[az_gila]

Originally Posted by Geico266

I found this while surfing around last night. Interesting design. Burt Rutan tried it on one of his daily flyiers, but removed it for reasons unknown.

http://www.liquidcooledairpower.com/cj-overview.shtml


Just thought I would share with you non traditional engine guys.

Rutan did use a Continental water cooled engine on the Voyager...

https://www.nasm.si.edu/research/aer...t/rutanvoy.htm

I think it was a one-off O-200 variant called an IOL-200

gil A

[Geico266]

The Rotax "9XX" series engines have water cooled heads. There are several reasons for this, elimination of detonation when using MOGAS is a big one. One of the side benifits is a toasty warm cabin using the waste heat through a heater core / forced air arrangement in the cabin. Makes for nice flying is zero F weather.

[N395V]

Ram offers a watercooled option on some of its Twin Cessna upgrade packages. They get very few takers.

http://www.ramaircraft.com/Aircraft-...V-Liq-cool.htm

[airguy]

Originally Posted by gmcjetpilot

The advantage or water cooling, tighter internal tolerances and better emissions.

Excellent point. One of the biggest advantages to water cooling is the extremely reliable thermal expansion window that the pistons/cylinders will operate in, which allows the designer to keep the tolerances tight, which facilitates high compression with very low oil consumption. Todays air cooled engines use a lot of oil partly because there is a lot of play between the piston and cylinder, which is required due to the operating temperature window. Putting water-cooled jugs on an air cooled engine will not improve this - you've still got loose tolerances. I see this product as a good add-on for tow planes or jump planes, and not much else besides specialized niche markets.

If you want the whole setup to work well, you need to design it that way from the word go, like the P-51 did with respect to the radiators and drag. In the case of water cooling, that means designing the engine from page one to be high power output, high duty cycle, water cooled, and tight tolerances. While you're at it, turbocharge it, keep the weight down, and design it to run LOP on cheap fuel.

Since I know George loves to rail against it (especially when I talk about it ) I'll say it again just for him - water-cooled turbodiesel!

[Tandem46]

Burt Rutan tried it on one of his daily flyiers, but removed it for reasons unknown.

Actually it was Dick, not Burt. Something bad happened and there was quite a bit of friction between Dick and LiquidAir.

As GMC said, this site is old. I came acrossed it it in 2001. It hasn't changed much. Dick emailed me in 2001 after I noticed he'd appeared to endorse the product. He told me to stay away from them.

[rv6ejguy]

The water cooled jugs guys have been floating around for many years but you just don't hear of many/ any people using them. Last updated 2001. Perhaps they are short on cash to perfect them and get all the bugs out. I don't think these will ever catch on in any big way. The current air cooled designs give pretty good service for most people if the CHTs are held below the recommended limits.

I like the Rotax idea of using water cooled heads and aluminum air cooled cylinders. This allows a sealed head casting with no cylinder junction/ gaskets. The heads are where all the heat is. This reduces the rad size considerably as you can see on most 912 installations. CHTs on the 912 rarely exceed 230F so the valve life is excellent and you don't get sticking valves or head cracking on these.

The power density of liquid cooled engines is far greater than air cooled engines. As far as the Reno reference goes, remember that the Merlins are ONE HALF the displacement of the Wright R3350s and Dago Red stills holds the fastest race record by over 20mph- 8 minutes of WOT. I don't buy the higher drag theory where a decent radiator setup is used, there are few facts to support this view.

Aluminum/ Nikasil cylinders might be a more useful change for the Lycoming. This would reduce weight, cylinder wear, reduce piston clearance and ring end gaps for better oil control, get rid of the old fashioned break-in procedures and use of mineral oil and have far superior heat rejection to steel barrels. The only downside is the base bolted jug design. Might have to be changed to a proper tension stud type retention system like Porsche and Rotax use. This would also stiffen and strengthen the whole assembly.

Anyone working on aluminum jugs for the Lycoming?